А.Шепс Самолеты Первой мировой войны. Страны Антанты

"Сопвич полуторастоечный" (1 1/2-Strutter) 1916 г.
  
   Кроме истребителей фирма "Сопвич" во время Первой мировой войны выпускала разведчик "Сопвич-двухместный". Из-за необычного расположения межкрыльевых стоек он назывался также "Сопвич-полуторастоечный".
   Эта машина конструктивно выполнена по той же схеме, что и другие самолеты фирмы "Сопвич" того времени.
   Отличался самолет большими размерами. Увеличены размеры и площадь оперения. Фюзеляж, крылья и оперение имели каркас из дерева и были обтянуты полотном. Стойки крыла и шасси были деревянные. Расчалки выполнялись из стальной ленты (на английских машинах) или троса (на машинах, строящихся по лицензии во Франции и России). Капот двигателя аналогичен самолету "Пап". Шасси с резиновой амортизацией.
   На самолетах, строившихся в России, в зимнее время устанавливалось лыжное шасси. На самолетах устанавливалось 2 пулемета: синхронный 7,69-мм "Виккерс" и на турели у наблюдателя - 7,62-мм "Льюис". Выпускались и одноместные машины без задней кабины.
   Двигатели ставились различные. На английских машинах в основном 9-цилиндровый, воздушного охлаждения, звездообразный "Клерже-9b" (130 л. с.). На французских и российских экземплярах кроме того ставили 7-цилиндровый, воздушного охлаждения, ротативный, звездообразный "Рон" (120 л. с.).
   В России самолеты "Сопвич-полуторастоечный" строились на заводах "Дукс" и В. А. Лебедева. Построено более 100 машин, которые состояли на вооружении до 1923 года.

В.Шавров История конструкций самолетов в СССР до 1938 г.

"Сопвич-разведчик" ( "Сопвит" , "Сопфит" , "Сопвис" , "Сопуит" - двухместный разведчик с двигателем "Клерже" в 130 л. с. (иногда "Рон" в 120 л. с.), один из основных типов самолетов советской авиации в гражданской войне. Его строили у нас серийно на протяжении 1917-1923 гг. Это была настоящая "рабочая" машина.

   Самолеты "Сопвич-разведчик" поступали в Россию по поставкам в 1917 г. в небольшом количестве, более 100 экземпляров их было построено и некоторое количество самолетов взято в качестве трофейных в 1919-1920 гг. По схеме это был одностоечный биплан с характерными наклоненными кнаружи стойками центроплана, из-за чего англичане называли его "полуторастоечным" бипланом. Расчалки коробки крыльев были двух типов: на английских экземплярах - профилированные стальные ленты, на французских - парные тросы с планкой между ними, обмотанные тесьмой. На самолетах русской постройки расчалки были одиночные тросовые. Вооружение - два пулемета.

   Была одна модификация "Сопвича" с двигателем "Оппель" в 185 л. с. и шасси от трофейного самолета "Румплер". Конструктор этой модификации - инженер В. П. Григорьев, заведующий мастерскими Киевского политехнического института.


Самолет||
Год выпуска||1916
Двигатель , марка||
   мощность, л. с.||130
Длина самолета, м||7,7
Размах крыла, м||10,2
Площадь крыла, м2||32,8
Масса пустого, кг||593
Масса топлива+ масла, кг||148
Масса полной нагрузки, кг||382
Полетная масса, кг||975
Удельная нагрузка на крыло, кг/м2||29,7
Удельная нагрузка на мощность, кг/лс||7,5
Весовая отдача,%||39
Скорость максимальная у земли, км/ч||149
Время набора высоты||
   1000м, мин||4,4
   2000м, мин||9,2
   3000м, мин||17,8
Потолок практический, м||4700
Продолжительность полета, ч.||3,5

H.King Sopwith Aircraft 1912-1920 (Putnam)

1 1/2 Strutter (land versions)

   In more ways than one the 1 1/2 Strutter was the most significant of all the Sopwith 1914-18 aeroplanes - not in the military and technical senses alone, but in its international acceptance as a novel and uncommonly efficient airframe (dependent though it was to remain throughout its life upon French-designed engines). In Great Britain, its country of origin, it had the additional significance of being the first Sopwith type to be sub-contracted on a truly vast scale.
   Here one draws attention to a parallel which, though quite remarkable in its closeness, seems to have passed unnoticed in the annals of the air: that is, the relationships which undoubtedly existed between this classic type of two-seat tractor fighter and the Vickers Gun Bus the classic type of two-seat pusher fighter. This is true not only in the military sense, but also in the international sense; for the Gun Bus, like the new Sopwith, was licence-built in France and was dependent on French rotary engines. In the purely Service sense the parallels are even stronger, for Admiralty interest was very marked in both instances not in the airframe alone (for both machines embodied novelties - the Gun Bus, for example, in its partly metal structure) but in the development of suitable armament. Both types, moreover, were tested and developed at Brooklands, and both were at one time intended to have a Smith radial engine; but even in 1915 it was declared of the Gun Bus: 'A most painstaking, and often disheartening, series of experiments were made with a view to making this pusher type machine the equal of the tractor type of aeroplane, and a measure of the success obtained can be gauged by the fact that it has now flown in a wind against which scarcely any headway could be made.’
   Certainly, compared with the 1 1/2 Strutter the Gun Bus was to make very little headway of any sort at all.
   Although in its definitive military form (and it will soon be clear that 'definitive' is used here solely for convenience) the design of the 1 1/2 Strutter is generally ascribed to late 1915, the time might be more truly set much earlier in that year, or even in late 1914; and that 'two-seater scout' was a description already current in the early summer of 1915 for the 'Sigrist Bus' (to use a familiar appellation) will be clear from a quotation that shortly follows. First it must be explained, however, that in the course of this quotation (describing the setting-up of a new British altitude record by Harry Hawker on 6 June, 1915) the qualified barograph reading of 'about 20,000 ft' proved inaccurate, thus accounting for the apparent discrepancy concerning Norman Spratt's unofficial performance on a B.E. - for Hawker's true height was 18,393 ft (5,606 m). Thus the quotation ran:
   'An altitude record is of distinct value for several reasons. First and foremost it connotes reserve of power. Secondly, provided it is made with a standard machine, not specially designed for the purpose, with neither pilot nor engine doped,' [a portent for Olympic Games to come?] 'it affords a direct standard of efficiency. Neither of these conditions was fulfilled in the case of the world's record held by the Germans. On July 14, 1914, Oelerich reached a height of 26,200 ft. in Germany, but his machine had been specially designed for the occasion; it was a 120 h.p. Beardmore-A.D.-engined D.F.W. biplane, and both pilot and engine were doped.’ (Sic: Does one detect here a tang of wartime propaganda, especially as the figure quoted for the German effort appears to be on the low side?).
   ‘Hawker's new British record' (continued the quotation) 'though inferior in actual height, is of a very different nature. It was made on a standard Sopwith two-seater scout, engined with an 80-h.p. Gnome of the ordinary type. True, the machine is slightly different in minor points of design from the Schneider Cup craft, notably in the chassis, with a single central skid and a new diagonal strut arrangement, of which it might he indiscreet to give particulars.'
   It was then recorded that 'The first 10.000 ft. were climbed in twenty minutes - 500 ft. per minute up to 10.000 ft. is some going went on steadily in the clear air and the intense cold, until the barograph needle had gone right off the chart, marked up to 6,000 metres, when the revolutions fell off to 1.100, and the climbing angle became exaggerated to the point of stalling. At this point Hawker deemed it expedient to come down; switching on and off, he made a long spiral, at the rate of 1,000 ft. a minute right over the aerodrome.' (This was Hendon - the Sopwith having flown there from Brooklands that morning). 'His vol plane lasted twenty minutes from a height of 20.000 ft. Switching on again, he made two splendid circuits over the course at full speed, having, curiously enough, lost none of his touch' (Hawker's hands were 'icy cold' even in the 'sweltering heat of the aerodrome") 'and finally alighted. His sealed barograph showed about 20.000 ft, subject to official correction. Thus Lieutenant E. F. Briggs' unofficial record (14.920 ft at Eastchurch. March 11, 1914, on an 80-h.p. Gnome Bleriot), and the unofficial record of Lieutenant Norman Spratt, amounting to some 18,900 ft., on a B.E., were both handsomely beaten, to the manifest delight of Tom Sopwith, who watched the while with perfect confidence.'
   The speed of this aircraft was given as 'upwards of 90 m.p.h.'. Its central-skid landing gear has already been mentioned though not the fact that this fitment was at some stage in the aircraft's career used to contain adjustable lead ballast (possibly when the machine was flown as a single-seater); but it was the 'diagonal strut arrangement, of which it might be indiscreet to give particulars' that was the essential novelty, the two halves of the top wing being braced by the W-form strut system, the outer arms (or struts) whereof reached so far outboard that their attachment-points might well have received a second pair of normal interplane struts (there was one pair in any case, further outboard) and thus suggesting the name '1 1/2 Strutter' - for did not the French have '1 1/2-wingers", or sesquiplanes, and were not both the Sopwith company, and Hawkers after them, much given to trying new biplane fighters with alternative single-bay and two-bay wings?
   With his usual professional touch Harald Penrose thus summarised the salient facts: 'At Kingston, Tom Sopwith's great factotum, the dour determined Fred Sigrist, as a result of discussion with Hawker on the possible form of a replacement two-seater with enhanced performance and safer characteristics, modelled a new fuselage on the 807 [see 'Folder Seaplane'] using a bigger fin having a rounded nose of bent tube, and stiffened the main wing spars in order to employ a single bay with outward-raking struts, shortening the lower wing proportionately [N.B. The 'Sigrist Bus', unlike the 'definitive' 1 1/2 Strutter, had wings of unequal span]. To reduce bending moments of the upper wing he used steel centre-section struts steeply sloping from the top longeron to a point well out in the spar bay, and then braced the centre-line juncture of port and starboard spars within inverted V-struts arranged like a trestle, resulting in a widespread transverse W. The machine had been growing slowly in a corner of the old Kingston Skating Rink, for Sigrist was preoccupied with production matters, and it would be another month or more before the framework was ready for covering. Meanwhile it was jocularly referred to by the workmen as 'Sigrist's Bus’.
   Further, it may now be pointed out, although it is sometimes correctly observed that the French Hanriot HD-1 fighter had a similar arrangement of inboard struts, it is no less cogent to remark that these struts braced far less of the span; and it might be more valid to submit that the 1 1/2 Strutter was a half-way step to full Warren-girder bracing - associated especially with Fiat and Handley Page - and that the centre portion of the W was to be seen on the Hawker Horsley and Hornbill. Far more remarkable, however, is the analogy of the Fiat C.R.42, the finest biplane fighter of the Second World War, an aircraft which had not only Warren-girder bracing for the outer wings but the 1 1/2 Strutter-style W bracing inboard. (Still one is left pondering how best might be described, in fractions, the centre-section struts of the 'progressively' modified Gloster fighters of the Gamecock era - culminating in the Goldfinch, with an N system instead of the W, though full Warren-truss bracing was nevertheless used for the ribs!).
   Whatever the full implications of the matter may be (and, all things considered, perhaps the RAF's homely Armstrong Whitworth Atlas affords the closest parallel, embodying, as it did, the inverted-V struts of the RFC's 'Little Ack' and 'Big Ack' with additional long splayed-out members) in the particular instance of Sopwith's 1 1/2 Strutter the novel wing-bracing arrangement for a biplane having no centre section was a peculiarly happy one. Certainly it differed radically from the arrangement on the Gordon Bennett single-seater (wherein the inboard struts were splayed in side elevation only) and it was one, furthermore, which helped to gain for the 'Strutter' - as it soon became known - not only military fame but its international acceptance also, the French themselves building 4,200 examples, some of which went to the Americans.
   Construction on this scale in France was, in itself, some tangible repayment of the debt accumulated by British aircraft-builders over the years to the Farmans (though Henri was a British citizen until 1937), to Bleriot and Voisin - and certainly not forgetting the flow of French engines, to which, as already noted, 1 1/2 Strutters were (so to speak) to remain permanently attached.
   While thus engaged in a general assessment of the 1 1/2 Strutter one must next reaffirm one’s contention that - its bombing and naval applications aside - this aeroplane is ‘justly remembered as the archetype of the classic two-seat fighter (pilot with fixed gun, gunner with free gun).' As for bombing and naval use, one might with equal justification have devoted separate chapters to fighters, bombers and chip's aeroplanes' (as they were called), as comprising the 1 1/2 Strutter spectrum; but one has plumped for compactness, and thus proceeds with development for land-based use, with fighting foremost - for we have already noted the early-1915 description of the aircraft as a 'scout'.
   Felicitously one can record at this point a visit by Harry Hawker to Hendon on 8 April, 1916, (the best part of a year after the one already mentioned) in what Flight described as 'the new two-seater ‘bullet'; and as at that period the terms 'scout' and 'bullet' were generically and loosely applied to the class of aeroplanes latterly known as 'fighters' it may reasonably be supposed that this aeroplane can be identified with the production-type 1 1/2 Strutter, built to the order of the RNAS, and capable of being armed to the requirements of that pioneering Service.
   This appearance by Hawker on the new Sopwith two-seater followed shortly upon another event which may now be seen to have been of no less significance in the history of the aircraft and the company alike. This event was a dinner given in the preceding January (1916) by the Sopwith employees for the directors, and graced by the presence of the Mayor of Kingston, who remarked that the occasion was something of a birthday party, for it was three years since the company had made a start at their Kingston works. Mr Sopwith declared that credit for the successful machines produced belonged to 'the fellows who had the getting out of the machines’, mentioning (evidently in the order now given) Mr F. G. Sigrist, Mr H. Hawker and 'the drawing office and charge hands'. Mr R. O. Carey, in his directorial turn (and before leading the Sopwith Works Band in a rendition to which he himself added a violin solo) referred to 'the excitement created by certain newspapers about the Fokker machine'. They must realise, said Mr Carey, 'that this kind of machine was a purely defensive one, and didn't worry our people a bit' because 'this country possessed something which would successfully outstrip a Fokker any day.' He then referred to the great kindness and consideration shown by 'the Naval resident inspectors'. Thus one may reasonably suppose that the unworried people mentioned were the Sopwith staff, and that the 'something' was the 1 1/2 Strutter, which was certainly an offensive, as well as a defensive machine; could indeed outstrip the Fokker (though by a narrow margin); and could certainly outfight it. And, in any case, the Pup was already well advanced.
   A special word will be in order here concerning 'the Naval resident inspectors' to whom Mr Carey rendered such grateful tribute; for numbered among these in 1915 was R. A. Bruce who, in that same year, joined the Westland Aircraft Works (founded during that April). To many people in the aircraft industry the name of Mr Bruce - together with that of Harald Penrose - was well-nigh identified in later years with Westland, and Bruce's eventual appointment as the company's managing director was a measure of his calibre. In this present instance it is fitting to note that the Westland-built Sopwith 1 1/2 Strutters were among the better-built examples.
   With fighting as our foremost concern in considering the 1 1/2 Strutter, we turn attention first to armament and then to the airframe - which embodied unorthodox features apart from the peculiar strut-arrangement. Thus, respecting armament, of particular importance were the guns, the mode of their installation and their manning.
   The pilot's fixed Vickers gun was mounted on the centre line of the fuselage, with the firing lever (when the Sopwith-Kauper synchronising gear was fitted, at least) projecting from the back of the gun. A Sopwith patented padded windscreen was fitted (to protect the pilot when he was taking aim) and plain open sights, or ring-and-bead sights, were mounted on the gun itself. This was the normal arrangement, though at least one early specimen had the Vickers gun mounted on the port upper longeron, with the breech casing lying under the built-up coaming of the cockpit. The ammunition (as was then standard for the Vickers gun, as for the Maxim gun from which it had been developed) was fed from the right, and a metal plate on the left, forward of the feed block, served to prevent the canvas belt from twisting in the slipstream before re-entering the protection of the fuselage. (The Prideaux disintegrating-link metal belt had not yet arrived). On some early examples the rear of the gun was partly faired.
   The 1 1/2 Strutter being primarily an RNAS aircraft (the first contract having been placed by the Admiralty in time for deliveries to start in February 1916 and the first operational machines being in action with No.5 Wing, RNAS, before April of that year was out) the entire gunnery scheme must be acknowledged largely to the experts of that Service (notably Warrant Officer Fredrick W. Scarff) but also to Sopwith themselves particularly in the person of Harry Kauper. Both the fixed-gun and the free-gun installations at first varied quite extensively, and apart from what has already been said about the Vickers gun scheme, it must be added that the first machines for the RFC (A and B Flights of No.70 Squadron, which went to the war a few weeks after the RNAS machines already mentioned) had gun-synchronising gear of the Vickers type, though C Flight of the same unit had aircraft which had been transferred from RNAS contracts, and which were fitted with the Scarff-Dibovsky gear developed for that Service. On a small scale, gears of Ross type were fitted to Strutters; and seemingly on a larger scale the Sopwith-Kauper gear, which is now rightly our concern.
   Harry (H. A.) Kauper - at one time foreman of the Sopwith fitters and already something of a hero in the earlier chapter on the Circuit Seaplanes - was the man chiefly responsible for this mechanical gear, which proved so successful that it lived on well into the Camel era. 3,950 sets having been supplied to the flying Services and 2,750 installed. The gear was developed in 1916, and there were several variations. Sopwith themselves once described it in the context of a cam operating a mechanism 'which directly caused the actuation of the firing lever of the gun’, at the same time remarking on 'the difficulty of obtaining a high rate of speed with these devices' because 'the inertia of the moving parts tends to prolong the period during which the automatic gun may repeat its movements and fire again, with the resultant risk of damage to the propeller.’ The essential components were, in fact, the cam already mentioned, and which allowed the actuation of a spring, which itself operated the firing mechanism. The cam was mounted on the engine 'in such a manner that it can oscillate the tappet rod in order to synchronise with the passage of the blades of the propeller past the line of fire of the gun, alternatively holding off or preventing the fire and then permitting the fire by means of the spring.’
   As for the 1 1/2 Strutter's free-mounted Lewis gun, the Scarff No.2 ring-mounting, with which the aircraft became almost identified and which Gen Trenchard quickly requested as standard on all future 1 1/2 Strutters for the RFC, was designed by Warrant Officer F. W. Scarff of the Air Department of the Admiralty, and in its development Sopwith played some part, the nature and extent of which is indeterminate. This most famous of all aircraft gun mountings was mainly constituted by an elevating-arm, or bow, which carried a Lewis gun, and a rotatable ring. It was contemporarily described as follows:
   ‘The elevating-arm and the rotatable ring are locked in their adjusted positions by devices which are actuated simultaneously, or in succession, to effect unlocking by a single control wire operated by a handle on the elevating-arm. When operated in succession, the ring is released before the elevating-arm. Elastic cords balance the turning moment in a vertical plane due to the weight of the elevating-arm and the parts carried thereby. The rotatable ring is mounted on ball or roller bearings.' Not mentioned in the foregoing concise description were the two upward-projecting pairs of toothed segments, or quadrants, each pair being engaged by a locking pin carried by the elevating-arm and moving into or out of engagement with the teeth of the segments. Of this basic form of Scarff ring-mounting there were several variations, not only British but foreign also, the best-known related foreign counterpart being the French T.O.3.
   This last-named mounting differed very greatly from the French-designed Nieuport type used on some early 1 1/2 Strutters, though the Nieuport mounting was itself basically of ring type. It had, nevertheless, a very distinctive appearance, by reason of its great height and peculiar form, these features resulting from a pair of upward-projecting arms, between which the Lewis gun was carried on a cross- member.
   Far less obtrusive was the British Strange mounting, a cranked-pillar pattern with which was associated a crescent-shaped toothed quadrant; but neither the Nieuport nor the Strange mounting was extensively fitted on the 1 1/2 Strutter - such was the demand for the Scarff, when it became available in quantity.
   One Sopwith contribution was a special seat for the gunner, capable of all-round movement about an eccentric pivot on a fixed stand, and having means for unlocking itself when relieved of the gunner's weight, enabling it to be freely rotated in its socket. Largely negating such refinements however (which were intended to enhance fighting efficiency) was the wide separation of the two cockpits by the fuel tank - a legacy from earlier Sopwith tandem two-seaters already described.
   For the Vickers gun of the 1 1/2 Strutter the belt held 300 rounds of .303 in ammunition, and for the Lewis gun a maximum of five 'double' (97-round) drums could be taken. Early 1 1/2 Strutters were sometimes supplied with 'single' (47-round) drums. Supplementary armament on one aircraft of B Flight, No.70 Squadron, was an 'automatic' (self-loading) pistol with oversize magazine, attached to the starboard landing gear struts to fire outside the propeller arc. Sopwith 'Two- seaters', as the 'fighter' versions of the 1 1/2 Strutter were sometimes called, sometimes had bomb-rails under the lower wings, possible loads being four or eight bombs of 20 lb or two of 65 lb.
   The airframe of the two-seat 1 1/2 Strutter was a remarkable combination of convention and novelty, the latter having been already instanced by the strut arrangement, though the wooden construction (with steel tubing used for tips and trailing edges) conformed with standard Sopwith practice. Three features that command special mention were the air brakes handwheel - actuated trailing-edge panels in the bottom centre section, pivoted spanwise to rotate upwards through 90 deg; the large adjustable tailplane (which, though having as a primary purpose compensation for gunners of different weights, was later popular with pupils, when numbers of 1 1/2 Strutters were used for training, because it enabled the trainees to fly with their chilly hands in their pockets); and third, the use of all-steel tubular construction for the elevators, fin and rudder.
   The unhappy separation of the pilot and gunner has been mentioned, but the pilot's upward view was also poor, though adequate forwards and downwards, while the siting of the gunner's cockpit, jointly with a top-wing cutout, afforded a wide field of fire for the Lewis gun. Somewhat disappointingly (for so much care had gone into the design) the 1 1/2 Strutter was officially declared to be 'rather heavy and slow on controls'; yet. even so, this aircraft marked a new departure in military-aircraft design, and was clearly capable of development and adaptation.
   After Hawker's early spectacular demonstrations (he was then flying solo) performance was never remarkable, either with the original 110 hp Clerget engine, or the later-standardised 130 hp Clerget (nor, for that matter, with any other Clerget or Le Rhone rotary, as fitted in some French-built machines), and this deficiency in performance, jointly with mediocre manoeuvrability, clearly militated against combat effectiveness - and, of course, the armament was quickly matched. Nevertheless, the type was in first-line service until late in 1917, by which time the Sopwith single-seaters had quite outclassed it in fighting performance. This being so it is the more regrettable that a project of September 1916, involving the fitting of an American-designed 150 hp Smith Static ten-cylinder radial engine, was never realised - and at that time there was no comparable A.B.C. radial available. (Clearly, a long inline engine would have spoiled the basic concept of the design).
   The foregoing reference to a ten-cylinder engine is a reminder that, however confusing were the Service or makers' designations of the rotary types actually fitted, these - for British operational service at least - invariably had nine cylinders, whereas the Pup sometimes had a seven-cylinder unit. The British-built 1 1/2 Strutters had either the 110 hp Clerget (makers' suffix 9Z) or the 130 hp Clerget (9B), but French-built examples had either Clergets of the 9B series (9Ba 135 hp, 9Bb 135 hp or 9Bc 145 hp) or the Le Rhone 9J (110 hp) or 9Jby (135 hp). French-built trainers sometimes had the 80 hp Le Rhone 9C, a type so popular in British operational Pups. The standard annular cowling on British 1 1/2 Strutters had a segmental slot at the bottom and was of special Sopwith design (see under Pup. in Harald Penrose's account).
   Development and adaptation now being our concern it is fitting to consider the special single-seat fighter version of the 1 1/2 Strutter developed for Home Defence. In this instance the Vickers gun was dismounted, the front cockpit was faired over, the pilot was moved to the rear, and a Lewis gun was mounted over the top wing to fire above the propeller and obviate the risk of using sensitive and temperamental 'special' ammunition in a synchronised gun. Presumably to exploit the '45-degree shot' upward-firing formula, on which much investigatory work was done, one aircraft at least had two upward-firing Lewis guns in a special installation forward of the cockpit, and in another application of two Lewis guns these were carried on a twin mounting of Foster (sliding block on curved track) type.
   Yet of far greater significance than these specialised single-seat fighters were the no less specialised single-seat bombers (as distinct from bomb-carrying two-seaters already mentioned). In essence the bomber transformation was simple: bombs were internally stowed in a compartment which took the place of the gunner's cockpit. On typical British 1 1/2 Strutter single-seat bombers, four 50 lb or 65 lb bombs were stowed horizontally. Beneath the bomb compartment were four trapdoors that were opened by the weight of the falling bombs (probably with scant effect on bombing accuracy) and were closed again by shock-absorber cord. In each side of the compartment were two inspection and access panels. The Vickers gun, was retained, and occasionally a Lewis gun firing over the top wing was additionally fitted though strictly as 'secondary' armament, for the ammunition magazine could not be changed in flight. Nevertheless, the possibility of abandoning the Vickers entirely may well have been in mind, for the later Sopwith B.1 bomber (another single-seater) had a single Lewis only.
  


1 1/2 Strutter (Ship's)

   Although the part played by Sopwith aircraft generally in the development of British Naval flying has been extensively recorded by other writers (and properly so) the contribution made by the 1 1/2 Strutter in particular has not, one feels, been fully recognised. In the 'Ship's Strutter' (as the basic form concerned was sometimes known, though commonly adapted from a landplane fighter or bomber) we see not merely an aeroplane capable of operating from a platform on a ship (or from a carrier's deck) but one that could perform in the pre-eminent roles that the Navy so urgently demanded should be filled: namely those of spotting fall-of-shot for the big guns of the Fleet(s) and of reconnaissance in general - aided by 'wireless'.
   Between the specially prepared shipborne versions of the 1 1/2 Strutter and the original form of the aircraft were analogies that were strikingly in parallel with those existing between the Hawker Hart of over ten years later and its Naval derivative the Osprey; and this was evident even in external appearance, for both could be seen with jury struts where the outer wing-panels were (on some Ship's Strutters) detachable or (on all Ospreys) foldable. Further, although in the Osprey there existed (supposedly at least) a 'fighter' element the official classification being 'fleet fighter-reconnaissance' - the pilot's armament was only half that of the corresponding specialised land-based fighter variant of the Hart (this, the Demon, having two Vickers guns and the Osprey one only) whereas on the shipborne 1 1/2 Strutter there was no Vickers gun at all, having regard to the pressing requirement to keep the aeroplane light while carrying its all-important wireless and other Naval appurtenances. By the same token, the Parnall Panther, which was specifically (and very ingeniously) designed to undertake essentially the same duties as the Ship’s Strutter, had a fixed Vickers gun in prototype form only, this being absent on production versions - with even more weight being saved by the adoption of a special pillar mounting for the defensive Lewis gun, instead of the generally adopted Scarff ring.
   To conclude the Ship's Strutter/Osprey analogies, even the apparently basic difference - the fitting of floats on the Osprey in its catapulted form - was, in fact, far from being as basic as appearances suggested; for catapults were not widely fitted to British Naval vessels until the 1930s, the two possible launching methods formerly used from battleships, battle cruisers and craft other than specialised aircraft carriers being the 'flying-off platform' built over a gun turret and rotating with it, or the technique of lowering a floatplane into the water by derrick and hoisting it back again.
   Herein lies the full Significance of the Ship's Strutter - it gave the Navy ears as well as eyes and claws; for on 4 April, 1918, (immediately after the formation of the RAF) an aircraft of this type, flown by Capt F. M. Fox of the new Service, and carrying an observer, W/T equipment and an Aldis signalling lamp was successfully launched from a platform on Q turret of the battle cruiser HMAS Australia. 'Successfully' here is emphasised, for an earlier trial from another battle cruiser (MHS Repulse, in March) had failed. Thus battleships and battle cruisers carried a two-seat reconnaissance aircraft (typically a 1 1/2 Strutter, though a Parnall Panther was used, for instance, from HMS Revenge) on a forward-turret platform, with a single-seat fighter (generally a Camel) on a rear-turret platform. By the end of the war, in fact, the Grand Fleet had over 100 platform-borne aircraft, 22 cruisers having themselves been given platforms - though not, of course, rotatable atop the turrets of big guns.
   The extent and importance of these provisions were little appreciated at the time by reason of wartime secrecy, but shortly after the Armistice a Naval officer gave this concise account: 'My ship carried one Camel and one 1 1/2 Strutter. These were carried on our broadside turrets. The 1 1/2 Strutter was used for spotting purposes, and the Camels in the squadron performed formation flying. The method of release is effected by a "quick-release". When about to fly off, the ship steams at about 30 deg. to the wind and the turret is trained 30deg., thereby pointing into the wind. The clamps are taken off the ailerons, elevators and rudder, and the quick-release attached. The pilot then starts his engine, and gradually works up to the maximum revolutions. When he waves his hand, the men holding on to the leading edge of the lower plane let go and stand clear, and at another signal, usually dropping a flag, given by the executive officer, the A. M. [air mechanic] pulls sharply on the quick-release and thus frees the machine, when the pilot runs along, and takes-off from, the platform. All the time when the engine is running the quick-release alone holds the machine. A tail guide of about 2 ft. length keeps the tail from dropping at the start. The greatest length of run for taking-off is not more than 30 ft.'
   This helpful little note is given here, rather than in the context of the Camel, with deliberate intent, for reconnaissance and spotting, rather than fighting, were (as noted in this chapter's opening paragraph) pre-eminent among the Navy's requirements. A brief word, too, on terminology may not be superfluous.
   First, the term 'broadside turret' must not necessarily be construed as archaic or tautologous, for not all turrets during 1914-18 were on the ship's centre line. Second, the Camels' 'formation flying' may reasonably be construed as 'flew in formation (or in company) with the 1 1/2 Strutters" just as, in later years, the single-seat Hawker Nimrods were dependent on the slower two-seat Ospreys for navigation (and found station-keeping a hindrance to their purpose). Last, even when flying-off platforms had become obsolete on Naval ships, the essential launching technique described was perpetuated in the aircraft carriers Furious, Courageous and Glorious for launching their 'slip-flight' fighters - sometimes using a quick-release - straight out of their hangar and over the bows below the level of the main flying-deck.
   Conversely, it is worth pondering the true origins of training the launching platform by a rotary mechanism; and here it may be noted that torpedo-tubes were mounted on turntables just as guns were mounted in rotating turrets. This being so one may further remark that well before the end of the 19th century a humorous fictional reference had been made to launching a flying machine from a ship of the Royal Navy by means of a veritable torpedo-tube. A relevant passage ran: '... the navigatin' commander give the correc' course to the torpedo lootenant, who trained the toobe by compass, an' fired.... (But perhaps this was a precursor of the aircraft catapult).
   To the earlier-quoted account by a Naval officer of how Sopwith aircraft were operated aboard 'his ship' it may be added that a technique was also developed whereby the aircraft was launched, as it were, in reverse, the guns being elevated to give a sleep run down the platform, but still into wind. A method involving downward launching from a ship had, in fact, been patented long before the war in the names of Capt F. M. Sueter, Lieut F. L. M. Boothby and Engr-Lieut H. G. Paterson, this method being applied jointly with a launching trolley, which was to drop into the water and be hauled on board again. Acceleration of the aircraft was assisted by a Wright-style falling weight. In the purely practical sense, Lieut C. R. Samson, on 10 January, 1912, had used a sloping staging, built over the forward gun turret (thus rendered unworkable) of HM Africa, to accelerate his pusher Short and secretly, it was said, 'Sammy' had done the job in the previous December.
   In the preceding chapter it was affirmed that 'On the Naval side' (and distinct from work described in this present chapter) 'bombing was pre-eminent'; and this particular theme may now be taken up by remarking that 1 1/2 Strutters were used for anti-submarine patrols not only in home waters but in the Mediterranean area also, the home-based patrols beginning in April 1917 and those in the 'Med’ about two months later. Thus, on 17 September of that year (by which time the 1 1/2 Strutter had been in service for about 1 1/2 years) an Otranto-based aircraft of this type was claimed to have sunk a U-boat with a 65 lb bomb.
   As a summation of other developments and as a basis for further comment one acknowledges this excerpt from Owen Thetford's British Naval Aircraft since 1912: 'At the Armistice some 170 Sopwith 1 1/2 Strutters remained in service with the R.A.F. and nearly 40 of these were at sea with the Grand Fleet. Indeed, when, in March 1918, HMS Furious was made the flagship of the Flying Squadron of the Grand Fleet her complement included fourteen 1 1/2 Strutters. For deck flying the 1 1/2 Strutter was used both with the normal wheeled undercarriage and with a special skid undercarriage first developed in trials at the Isle of Grain; the latter version usually had a hydrovane mounted at the front end of the skids to prevent the aircraft nosing over if forced into the sea. This device, as well as the inflatable air-bags located either side of the engine, remained a feature of naval aircraft until about 1923, when flotation equipment was mounted inside the rear fuselage instead.'
   To these remarks one would add that, before ditching a 1 1/2 Strutter, it was advisable (one experienced pilot said 'necessary') for the pilot - seated as he was under the centre section - to get out on the bottom wing. Further points that one now makes revert to the earlier Sopwith/Hawker analogies and to the development of flotation gear generally. Whereas the Hawker Nimrod and Osprey had (in common with other Fleet Air Arm types of their period) air-bags of the officially-styled 'permanent atmospheric-pressure type' as part of their normal equipment, the land-based Hart bomber was not thus endowed. So, when over-water dive-bombing became a requirement, flotation gear had to be provided as an 'extra' - just as it had been on the 1 1/2 Strutter and although this gear took two quite distinct forms (inflatable bags in under-wing containers, or a Youngman dinghy, as fitted on some Ospreys, and housed at the root of the top starboard mainplane, between the spars) both forms were inflatable again as on the 1 1/2 Strutter.
   Another fitment of the general type which was to reappear on the Nimrod and Osprey was the arrester hook with which experiments were made on the dummy deck at the Isle of Grain (particularly associated with Harry Hawker's compatriot Harry Busteed) in June 1918. The 1 1/2 Strutter used was a skid-equipped single-seat bomber, though the significance of this fact should not be over-estimated, for many types of aircraft were used as experimental 'hacks', and the absence of a gunner and internal bombs may have been deemed especially beneficial respecting c.g. position and flying weight, for the hook was attached far forward under the fuselage. These considerations notwithstanding, the claim by Vice-Admiral Richard Bell Davies that the idea of 'detachable-wing 1 1/2 Strutters' of 'the long-range single-seater bomber' type was his own (for attacking Zeppelin bases) is not to be ignored.
   Clips on the landing gear spreader-bar were ultimately favoured to effect arrest, and were to be generally used on British carrier-borne aircraft pending the return of the under-fuselage hook. The pilot who pioneered this 'clip' technique has, in fact, already been named in a loftier rank: he was Lieut Col R. Bell Davies, VC, DSO, and the aircraft concerned - on 1 October, 1918 was 1 1/2 Strutter F2211, which, when flown from and landed aboard HMS Argus, had a special propeller guard.
   The full extent of Naval experiments with the 1 1/2 Strutter may never be known; but one that must clearly be recorded is that wherein fore-and-aft troughs, as developed at the Isle of Grain, laid along a special deck on HMS Vindex received the landing-gear skids of another experimentally-employed single-seat bomber. This particular aeroplane was the Westland-built N5601, and there is ample evidence that more than one aircraft from the same batch was used for Naval experiments of various kinds with inflatable air-bags for instance. Westland's own first major contribution to British Naval flying was, as matters transpired, an adaptation of another of their products the Walrus, for which the D.H.9A provided the basis, but which utilised the hydrovane landing gear and inllatable air-bags as developed on the 1 1/2 Strutter.
   To the 1 1/2 Strutter the US Navy, as well as the British, owes a debt for pioneer experiments and operations. Apart from a single specimen shipped to the USA and numbered there A5660, twenty-one additional examples were obtained from the US Army after the war. Thus the 'yellow rose' that bloomed on the turret platform of the USS Texas in 1919 was really planted at Kingston, Surrey, England.
   At the very outset of this account deliberate allusion was made to 'specially prepared shipboard versions' (plural) of the 1 1/2 Strutter; and any attempt at a precise definition of the common appellation 'Ship's Strutter' (or Ship Strutter) would be hazardous. However, that the Isle of Grain should have primary credit for the detachable wings, skid-type landing gears, hydrovanes, flotation gear - even, perhaps, for that all-important 'wireless' (W/T) - used by aircraft of this general denomination is likely. That conversion sets were later ordered from the Gosport Aviation Co. is hardly less credible, though this order appears to be quite unconnected with the fact that Sopwith's R. J. Ashfield had joined Gosport around the turn of 1917. With the Isle of Grain also was associated the development of a special lightweight gun-mounting for the Ship's Strutter, though whether this was of the pillar type fitted to the Parnall Panther or of a specially lightened Scarff pattern (the Scarff, in any case, taking many forms) is uncertain. With Grain development, too, was associated a Clerget engine having a nominal output of 140 hp - in which regard it may be noted that the 9BF pattern was described by Gwynnes Ltd, of Hammersmith (‘Sole licencees for the British Empire’) as having a stroke of 172 mm (that of the 130 hp 9B being 160 mm) and a nominal power of 150 hp. (For French ratings see previous chapter). Concerning the long-stroke Clerget it may also be pertinent to note in the present context that in February 1918 an official Information Circular was issued comprising notes on the conversion of the 9B engine to what was designated (verbatim) 'the 9B.F. (Long Stroke) Clerget Engine’. As no Vickers gun was fitted to the Ship's Strutter any increase in cowling diameter would be of small consequence.

F.Manson British Bomber Since 1914 (Putnam)

Sopwith 1 1/2-Strutter Bomber

   Design of the Sopwith 1 1/2-Strutter probably began quite early in 1915 although, being in effect a private venture at the outset, manufacture of a prototype at Kingston was accorded less urgency than to aeroplanes being prepared to specific Admiralty orders. As with most of the early Sopwith aircraft, delineation of design responsibility was nebulous, frequent informal discussions on new designs being held between Thomas Sopwith himself, his works manager Fred Sigrist, and his chief pilot Harry Hawker, with R J Ashfield and Herbert Smith representing their respective design offices.
   Being almost exclusively involved with Admiralty requirements, Sopwith would have been familiar with that Ministry's shift towards bombing aircraft during 1915 (away from purely torpedo-carrying seaplanes), yet no less aware of the Army's desperate shortage of effective light tactical bomb-carrying aeroplanes, and in particular such aeroplanes capable of defending themselves in the presence of German fighting scouts.
   The 1 1/2-Strutter (so called on account of the shortened inboard wing struts being attached to the upper longerons and not extending down to the lower wing spars) was therefore deliberately intended to attract both Admiralty and War Office orders for a self-defensible light bomber. Designed initially as a two-seater, it was provided with a Lewis gun on the rear cockpit and later a fixed, front Vickers gun, firing through the propeller, made possible by the Vickers and Scarff-Dibovski synchronizing gears. The former gear was preferred by the War Office, the latter by the Admiralty.
   Structurally the 1 1/2-Strutter was entirely conventional by Sopwith standards, that is to say it was of all-wood construction with ply and fabric covering; ailerons were fitted to upper and lower wings, which were of equal span. Early aircraft were fitted with the 110hp Clerget engine, but also came to be powered by the 130 and 135hp Clergets and Le Rhone engines of similar power.
   The aircraft featured two interesting innovations which served to demonstrate the efforts made to alleviate any handling difficulty that might arise when carrying and dropping bombs. These were a pair of rudimentary airbrakes set in the lower surfaces of the wing centresection, and a variable-incidence tailplane, adjustable by a control wheel in the pilot's cockpit to compensate for variations in trim. The latter innovation was patented by Harry Hawker and, in 1920, when the Sopwith company went into liquidation, the patent rights were determined in favour of the H G Hawker Engineering Company. (The variable-incidence tailplane was to be a feature of most Hawker aircraft produced between 1926 and 1935, as well as others)
   The prototype, No 3686, was placed on an Admiralty contract, and probably first flew at the end of December 1915 or early the following month. It was followed by numerous production contracts - which were widely subcontracted - from the Admiralty (where the aircraft was referred to as the Type 9700) and War Office, the majority of the former being for bombers, and the latter for fighters. The 50 naval aircraft of the first production order, built by Sopwith, were two-seaters, but it was quickly decided that, when carrying the normal bomb load (of up to four 65 lb bombs in an internal fuselage bay), it was necessary to fly without the observer/gunner, with the result that all subsequent Admiralty orders for bombers required the rear cockpit to be deleted altogether, and faired over. The front gun was, however, retained. A total of 172 naval single-seat bombers was built by Sopwith, Westland, and Mann, Egerton.
   It is perhaps worth recording here that it was Warrant Officer F W Scarff at the Admiralty Air Department who drew up the design of the front gun synchronizing gear from proposals made by a Russian, Lt-Cdr V V Dibovski, and that Scarff it was who also designed the gun mounting ring that was to carry his name in the RAF for a quarter century. Some 1 1/2-Strutters were fitted with a Nieuport ring of French origin, but when two-seater naval aircraft were transferred to the RFC at the time of the great summer battles o f 1916, General Trenchard ordered all his Service's 1 1/2-Strutters to be converted to have Scarff rings, so superior were they found to be.
   The arrival of the 'Strutter' bomber in the RNAS was intended to be central to the build-up of a bombing campaign by No 3 Wing, based at Luxeuil, but this plan was severely delayed when the Admiralty agreed to transfer more than 70 of these aircraft to the RFC to help make good the losses being suffered during the Somme battle of July.
   Despite these delays, naval 1 1/2-Strutters flew a number of outstanding bombing attacks during the summer of 1916, including raids on the airships stations at Evere, Berchem Ste Agathe and Cognelee, an ammunition dump at Lichtervelde and the shipyards at Hoboken, serving with Nos 5 and 8 (Naval) Squadrons.
   Apart from anti-submarine coastal patrols, which 1 1/2-Strutters flew as stopgap equipment from such stations as Mullion, Pembroke and Prawle Point, the aircraft gave long service with the RNAS in the Mediterranean both as anti-submarine aircraft and bombers in Italy, Macedonia and the Aegean (probably sinking an enemy submarine with a 65 lb delayed-action bomb on 17 September 1917).
   The aircraft were also supplied to a number of Allied air forces, in most instances as two-seat fighters or reconnaissance aircraft, although France (where the 1 1/2-Strutter was also licence-built by Liore et Olivier and Hanriot) also received single-seat bombers.

   Type: Single-engine, single- and two-seat, single-bay biplane light bomber.
   Manufacturers: The Sopwith Aviation Co Ltd, Kingston-upon-Thames, Surrey; Mann, Egerton & Co Ltd, Prince of Wales Road, Norwich, Norfolk; Morgan & Co, Leighton Buzzard, Bedfordshire; Westland Aircraft Works, Yeovil, Somerset.
   Powerplant: One 110hp Clerget 9Z or 130hp Clerget 9Bc nine-cylinder rotary engine driving two-blade propeller.
   Dimensions; Span, 33ft 6in; length, 25ft 3in; height, 10ft 3in; wing area, 346 sq ft.
   Weights (Clerget 9Z): Tare, 1,354 lb; all-up (with four 56 lb bombs), 2,362 lb.
   Performance (Clerget 9Z): Max speed, 104 mph at sea level; climb to 10,000ft, 26 min 55 sec; service ceiling, 12,500ft.
   Armament: One synchronized 0.303in Vickers machine gun on nose decking; bomb load of four 65 lb bombs or equivalent weight of lighter bombs carried internally in bay aft of the pilot's cockpit.
   Production: No special bomber prototype. Of the total of 1,513 Sopwith 1 1/2-Strutters recorded as having been ordered for the RFC and RNAS, 172 were built as single-seat bombers: Sopwith, 145 (Nos 9651, 9652, 9655, 9657, 9660, 9661, 9664, 9666-9673, 9700, 9704, 9707, 9711, 9714, 9715, 9718, 9720, 9723, 9724, 9727, 9729, 9732, 9733, 9736, 9738, 9741, 9742, 9745 and 9747; A6014 and A6015; N5088 and N5089; N5120-N5179; N5500-N5537 and N5550-N5559); Morgan, 2 (A6014 and A6015); Mann, Egerton, 20 (N5200-N5219); Westland, 5 (N5600-N5604).
   Summary of Service: Sopwith 1 1/2-Strutter single-seat bombers served with 3rd and 5th Wings, RNAS, in France, and with RNAS units in Italy (at Otranto), Macedonia and the Aegean, including 'F' Squadron which flew a number of bombing raids in the Smyrna area.

P.Lewis British Bomber since 1914 (Putnam)

Another manifestation of the Admiralty’s determination to adhere to its policy of keeping the R.N.A.S. on the offensive came with its order for the Type 9700 from Sopwith. The prototype, 3686, was completed at Kingston in mid-December, 1915, and emerged as a single-bay staggered biplane with equal-span wings of 33 ft. 6 in.
   The designation Type 9700 lapsed into obscurity immediately, as the appearance of the newcomer brought the name of 1 1/2-Strutter, by which it was to be known ever afterwards. The unusual appellation is generally conceded to have arisen from the use of pairs of short and long centre-section struts. A second noteworthy feature of the 1 1/2-Strutter lay in its introduction of the urgently-needed and long-awaited synchronizing gear to allow a front gun - in this case a single Vickers machine-gun - to fire ahead through the propeller arc. Two further innovations in the 1 1/2-Strutter were the ability to adjust in flight the incidence of the tailplane and the incorporation of airbrakes in the trailing edge of the lower wings’ centre-section. These consisted of a pair of panels hinged to turn upwards in opposition to the airflow. The 1 1/2-Strutter was without any particularly radical features in its design and followed the firmly established Sopwith style of a well-proportioned conventional layout, a practice which had already demonstrated itself as a sound formula for success in the majority of projects.
   Success was certainly to attend the 1 1/2-Strutter in its career, both in the R.N.A.S., which ordered one hundred and fifty initially, and in the R.F.C., which subsequently took the machine into its ranks. The R.N.A.S. received its first Type 9700s in the early part of 1916 and immediately put them to use as bombers and bomber-escorts. As was often the case with the early two-seaters, the 1 1/2-Strutters were at times flown solo to enable a reasonable load of bombs and fuel to be carried. The early naval versions utilized the Scarff-Dibovski gear to synchronize the pilot’s Vickers, but, later on, both Ross and Sopwith-Kauper gears were installed. The observer defended the machine with the usual Lewis gun, at first on a Scarff pillar mounting and subsequently on Nieuport and Scarff No. 2 rings.
   The 1 1/2-Strutter was regarded with enough favour by the Admiralty for a special single-seat version to be developed as a long-range bomber. The machine was flown from the front seat and the load of up to twelve bombs was housed in a compartment to the rear of the pilot. Occasionally, a single Lewis gun was mounted on the upper centre-section in addition to the standard Vickers on the nose. 1 1/2-Strutters were responsible also for carrying out many patrols against U-boats.

P.Lewis The British Fighter since 1912 (Putnam)

In the course of 1915, the Sopwith Aviation Company’s design office had prepared drawings for a two-seat biplane which was destined for a very successful career and for particular distinction as the first British tractor aircraft produced with a properly synchronized gun for the pilot to fire forward between the spinning propeller blades. With the construction of the prototype during the last few weeks of 1915, the Sopwith firm placed at the disposal of the Services a machine which was a great step forward in equipment.
   Apart from its advanced armament installation there was nothing radical about the new Sopwith, which officially to the R.N.A.S. was the Sopwith Type 9700 and to the R.F.C. the Sopwith Two-Seater. However, neither of these designations was that under which the machine passed into its distinguished niche in the annals of British military aircraft. Universally, it became the 1 1/2-Strutter, an appellation which is generally conceded to have evolved through the unusual arrangement of short and long pairs of centre-section struts. Powered by the 110 h.p. Clerget, the 1 1/2-Strutter represented a logical development, embodying the valuable experience in the techniques of design and construction amassed by the Company during the past few years.
   The pilot’s single Vickers gun was installed centrally on the front decking and, in the case of those used by the R.F.C., was synchronized with Vickers-designed gear, while those ordered for the R.N.A.S. used the Scarff-Dibovsky gear. As well as providing for the first time a fully effective weapon for the use of the pilot, the 1 1/2-Strutter carried a Lewis gun in its rear cockpit. The simple and rather restrictive Scarff-designed socket-and-pillar fitting for the rear gun, employed for the first 1 1/2-Strutters, was replaced on later versions for a while by the Nieuport ring type of mounting which bestowed greater mobility on the gun. The Nieuport mounting was not ideal, owing to its awkward arrangement and size, and Wt.Off. Scarff was not long in devising a great improvement with his No. 2 ring mounting. The Sopwith-Kauper and Ross gears were also installed for the front gun in later examples of the 1 1/2-Strutter.
   In addition to its armament innovations, the type incorporated a tailplane with variable incidence, which was altered during flight by a wheel control in the pilot’s cockpit, and hinged flap airbrakes in the lower wing roots.
   The Admiralty was earliest to show interest in the 1 1/2-Strutter as equipment for the R.N.A.S. and started the ball rolling with an initial order for one hundred and fifty, the first of which became available early in 1916. The R.N.A.S. commenced to use their machines with success as bombers and intended to develop such attacks on the Germans. However, the R.F.C. was so short of suitable aeroplanes prior to the opening of the Battle of the Somme, that, following a request from the War Office, the Admiralty agreed to transfer a considerable number of its 1 1/2-Strutters. The R.F.C. had also, on its own account, ordered 1 1/2-Strutters for its re-equipment, the initial machines of the procurement going to No. 70 Squadron. The type soon proved its worth over the battle front and was a welcome and reliable addition to Allied air strength.
   In retrospect, the Sopwith 1 1/2-Strutter is seen as the pioneer of the classic two-seat, tractor fighter layout, a concept which was to be exploited and developed to a very high degree for the ensuing two decades.

F.Mason The British Fighter since 1912 (Putnam)

Sopwith 1 1/2-Strutter
  
   This quaintly-named aircraft earned its place in early British military aviation history as the first RFC and RNAS fighter to be provided with a machine gun synchronized to fire through a tractor propeller for, owing to the previous lack of a reliable synchronizing gear, British fighting scouts had employed free-firing guns mounted in the nose of a nacelle with a pusher engine in the rear. Moreover, because it was now possible to accommodate a gunner in addition to the pilot, the 1 1/2-Strutter became the first British operational two-seat fighting scout and thereby created a design formula that was to survive in the RFC and RAF for more than a quarter century. The 1 1/2-Strutter is thought to have owed its name to the arrangement of the centreplane struts which, being attached to the top fuselage longerons, did not extend the full depth of the interplane gap. In service with the RNAS the aircraft was officially termed the Sopwith Type 9700 and in the RFC the Sopwith Two-Seater.
   The structure of the 1 1/2-Strutter followed conventional Sopwith practice, the wire-braced wooden box members of the fuselage being fabric-covered aft of the gunner’s cockpit, and forward by plywood sheet. The pilot was situated directly below the top wing centre section with a single Vickers machine gun mounted centrally on the nose and engine cowling. The observer’s position was some four feet aft of the pilot, the intervening space being occupied by the main fuel tank. Several front gun synchronizing systems appeared in 1 1/2-Strutters, including Vickers-Challenger, Scarff-Dibovski, Ross and Sopwith-Kauper, and either Nieuport or Scarff ring mountings were used for the Lewis gun on the observer’s cockpit. An unusual feature at the time was the provision of an adjustable tailplane whose incidence could be controlled by a wheel in the cockpit.
   The 1 1/2-Strutter was originally ordered by the Admiralty both as a two-seat fighter and as a light bomber, and the first prototype, No. 3686, was first flown in mid-December 1915 by Harry Hawker. The early orders for 150 aircraft were placed with Sopwith for the RNAS, of which the last 35 were singleseat bombers, the remainder two-seat fighters. Other orders were placed for the RFC with Sopwith, Fairey, Vickers and Ruston, Proctor for about 600 two-seat fighters. However, shortly before the Battle of the Somme, it was reported that the RFC was desperately short of fighting aircraft in France, with a result that the Admiralty agreed to transfer a total of 77 1 1/2-Strutters to the RFC, all of them two-seat fighters.
   The 1 1/2-Strutter evidently impressed its pilots from the outset, the attractively compact aircraft being powered initially by a 110hp Clerget rotary, which bestowed a speed of 107 mph at sea level. Production aircraft from the Sopwith and Ruston, Proctor factories began appearing in April 1916, the Admiralty’s bombers being delivered that month to No 5 Wing, RNAS at Coudekerque in France, and the RFC’s fighters joining Nos 45 and 70 Squadrons at Gosport and Farnborough respectively, also in April. Such was the shortage of fighters on the Somme front that No 70 Squadron began flying its 1 1/2-Strutters to France in May, and the first of the ex-RNAS transfers joined the Squadron’s ‘C’ Flight and followed in July. These were the only RFC 1 1/2-Strutter squadrons to see action over the Western Front during 1916, delivery of new aircraft being slow to accelerate, and No 45 Squadron did not in fact complete its establishment until the last day of September. The RNAS, in addition to its transfer of 1 1/2-Strutters to the RFC, also ‘lent’ one Flight of ‘Naval Eight’, the famous No 8 (Naval) Squadron which also flew the aircraft for a short period.
   Although increasingly outclassed by the newly-arrived Albatros D Is, armed with a pair of Spandau front guns and possessing a top speed of 109 mph, the 1 1/2-Strutter acquitted itself well, largely on account of its own front gun which, in the early weeks, appeared to take the Germans unawares. Nevertheless, it was by no means as nimble as the German single-seaters, and casualties began to mount on the two Squadrons. Towards the end of October No 45 Squadron lost three of its aircraft in a single day.
   Only one other Squadron, No 43 (later famous as ‘The Fighting Cocks’), flew 1 1/2-Strutters in France, arriving in January 1917. By then the aircraft were being delivered with 130hp Clerget engines, but the additional power did little to improve the aircraft’s performance significantly. No 43 Squadron flew its aircraft with distinction in trench attacks during the Battles of Arras and Messines.
   The heavy casualties suffered by the RFC in France during ‘Bloody April’ served to emphasise the desperate need to introduce new fighting scouts into service to counter the new Albatros and Fokkers which had begun to dominate the skies over France. The 1 1/2-Strutter started to be replaced in France from July 1917, although three other Home Defence Squadrons of the RFC (Nos. 37, 44 and 78) began receiving the aircraft in the same month, but most had disappeared from operational service by the end of that year, replaced by Sopwith Camel single-seaters. Only No 78 Squadron retained 1 1/2-Strutters, at Suttons Farm, until July 1918.
   Various figures have been quoted for the total production of Sopwith 1 1/2-Strutters, and the number most usually quoted by generally reliable sources is 1,534; it is also stated that as many as 4,500 examples were built under licence in France by Liore et Olivier and Hanriot, of which 514 were purchased for the American Expeditionary Force. At least three squadrons of the Belgian air force flew 1 1/2-Strutters, and some aircraft reached Russia. Shortly before the Armistice twenty aircraft were supplied to Romania, and other examples flew in Latvia and Japan.


   Type: Single-engine, single- or two-seat biplane fighter or light bomber.
   Manufacturers: The Sopwith Aviation Co Ltd, Kingston-upon-Thames; The Fairey Aviation Co Ltd, Hayes; Hooper & Co Ltd, Chelsea, London; Mann, Egerton & Co Ltd, Norwich; Morgan & Co, Leighton Buzzard; Ruston, Proctor & Co Ltd, Lincoln; Vickers Ltd, Crayford; Wells Aviation Co Ltd, Chelsea, London; Westland Aircraft Works, Yeovil; F. Liore et Olivier, Levallois-Perret, France; Hanriot et Cie, Billancourt, France.
   Powerplant: One 110hp Clerget 9Z or 130hp Clerget 9Bc nine-cylinder rotary engine (also 80hp Le Rhone 9C, 110hp Le Rhone 9J, 130hp Le Rhone Jby, and 135hp Clerget 9Ba)
   Structure: All-wooden construction with fabric and plywood covering.
   Dimensions: Span, 33ft 6in; length, 25ft 3in; height, 10ft 3in; wing area, 346sq ft.
   Weights (two-seat fighter): Tare, 1,305lb; all-up, 2,150lb.
   Performance (two-seat fighter, Clerget 9Bc): Maximum speed, 107mph at sea level; climb to 10,000ft, 17 min 48 sec; service ceiling, 15,500ft; range, approx. 230 miles.
   Armament (two-seater): One fixed, synchronized forward-firing 0.303in Vickers machine gun on nose, and one free 0.303in Lewis machine gun on Nieuport or Scarff mounting on rear cockpit.
   Prototype: One, No. 3686 (first flown by Harry Hawker in December 1915)
   Production (fighters only; approx, figures): Sopwith, 161; Fairey, 100; Hooper, 100; Mann, Egerton, 55; Morgan, 150; Ruston, Proctor, 350; Vickers, 150; Wells, 100; Westland, 50. Overseas (all versions), figure of 4,500 quoted.
   Summary of Service (fighters only): Nos 37, 43, 44, 45, 70 and 78 Squadrons, RFC and RAF; Nos 5 and 8 (Naval) Squadrons, RNAS. (Also thirteen Escadrilles of l'Armee de I’Air, three squadrons of the Belgian Flying Corps, and 88th, 90th and 99th Aero Squadrons of the US Air Service).

W.Green, G.Swanborough The Complete Book of Fighters

SOPWITH 1 1/2-STRUTTER UK

   Deriving its extraordinary appellation from a characteristic arrangement of cabane struts - a name that was initially unofficial, but came to be accepted as a result of common usage - the 1 1/2-Strutter was both the first British aircraft to be built with a synchronised gun as standard equipment and the first true two-seat fighter to see RFC service. Designed and built for the Admiralty, the unarmed prototype was completed in December 1915, and series deliveries to the RNAS followed from February 1916. A single-bay biplane of wooden construction with fabric skinning, the 1 1/2-Strutter featured air brakes in the lower wing and an adjustable-incidence tailplane. At an early production stage, armament was standardised on a synchronised 0.303-in (7,7-mm) gun with a second weapon of similar calibre on a Scarff ring mounting in the rear cockpit. The 1 1/2-Strutter was used by the RNAS in both escort and (without observer) bombing roles, and 77 of the first 150 aircraft ordered by the Admiralty were transferred to the RFC owing to the exigencies of the times. A single-seat bomber version of the 1 1/2-Strutter was built in parallel, some examples of this variant being converted as two-seat fighters. Initial production aircraft were powered by the 110 hp Clerget 9Z nine-cylinder rotary engine, but, in the autumn of 1916, this gave place to a 130 hp Clerget 9B. At least 1,513 1 1/2-Strutters were built in the UK (by the parent company, Fairey Aviation, Hooper & Co, Mann, Egerton & Co, Ruston, Proctor & Co, Vickers Ltd, Wells Aviation and Westland Aircraft). The 1 1/2-Strutter was licence-built in France as a single- and two-seat bomber (SOP 1B1 and 1B2) and two-seat reconnaissance aircraft (SOP 1A2), primarily with the 110 hp and 135 hp Le Rhone 9J and 9Jby nine-cylinder rotaries, 4,500 allegedly being produced by Liore et Olivier, Hanriot, Amiot, Bessoneau, Darracq, REP and Sarazin Freres. The US government procured 514 from France, and others were supplied to Belgium and Imperial Russia. The following data apply to the 130 hp Clerget-engined model.

Max speed, 100 mph (161 km/h) at 6,500 ft (1 980 m).
Time to 6,500 ft (1 980 m), 9.15 min.
Endurance, 3.75 hrs.
Empty weight, 1,305 lb (592 kg).
Loaded weight, 2,150 lb (975 kg).
Span, 33 ft 6 in (10,21 m).
Length, 25 ft 3 in (7,69 m).
Height, 10 ft 3 in (3,12 m).
Wing area, 346 sqft (32,14 m2).

J.Bruce British Aeroplanes 1914-1918 (Putnam)

Sopwith 1 1/2-Strutter

  THE first Sopwith aeroplane to make a resounding name for itself was the quaintly-named 1 1/2-Strutter. More than one reason has been given for the machine’s odd name, but the most credible seems to be that which attributes it to the outer struts of the central wing-bracing: these were said to look like half-size interplane struts which, by virtue of their shortness, had to be attached to the upper longerons instead of to the lower wing. Originally, of course, the name was unofficial. To the Admiralty the machine was known as the Sopwith Type 9700, and the R.F.C.’s first official designation for it was Sopwith Two-Seater.
  The 1 1/2-Strutter was first built for the Admiralty. The prototype was completed late in 1915, and was passed by the Sopwith experimental department on December 12th, 1915. It was a handsome two-seat biplane, powered by a 110 h.p. Clerget rotary engine which was installed on an overhung mounting and had a circular open-fronted cowling. The single-bay wings were of equal span, and were characterised by the W-shaped arrangement of cabane struts which had first appeared on the so-called Sigrist Bus.
  The 1 1/2-Strutter was the first Sopwith aeroplane to have the shape of fin and rudder which was to appear, in easily recognisable variations, on many later Sopwith types. It was also fitted with the characteristic Sopwith undercarriage, in which each wheel was mounted on a half-axle with its inner end pivoted at the mid-point of the spreader-bars; shock absorption was by means of the rubber cord which bound each half-axle to the apex of the corresponding vee-strut.
  The structure of the 1 1/2-Strutter was quite conventional: wire-braced wooden members were covered with fabric, with plywood decking about the cockpits. The pilot sat directly under the upper wing, and the observer’s cockpit was some way aft; the space between the cockpits was occupied by the main fuel tanks.
  Two features which were unusual in 1915 were the adjustable tailplane, the incidence of which could be varied in flight by means of a control-wheel in the cockpit, and the air-brakes. The latter consisted of two square surfaces in the trailing portion of the lower centre-section; when fully applied these surfaces tilted upwards until they were at right angles to the airstream. Their hinges were set back a short distance from their forward edges: thus a balancing effect was obtained from the small portion which projected below the wing. These air-brakes in no way resembled latter-day trailing-edge flaps.
  The Admiralty ordered 150 Sopwith 1 1/2-Strutters for the R.N.A.S., and deliveries began in the early spring of 1916. By the end of April that year, No. 5 Wing of the R.N.A.S. at Coudekerque had one Flight of the new type. The Wing had arrived at Coudekerque only in the preceding month, and was intended to serve as a bombing unit. The 1 1/2-Strutters were used both as escorts to the Caudron G.IVs and Farman 40s, and as bombers in their own right.
  On August 9th, 1916, Flight Sub-Lieutenants R. H. Collet and D. E. Harkness flew their 1 1/2-Strutters without observers to bomb the airship sheds at Evere. Each pilot dropped eight le Pecq bombs on the large hangar, and Harkness dropped four more on the hangar at Berchem Ste. Agathe. On the 18th, four 1 1/2-Strutters bombed an ammunition dump at Lichtervelde and left part of it burning; on the 25th, two Sopwiths bombed the Zeppelin hangars at Cognelee; and on September 2nd, three of No. 5 Wing’s 1 1/2-Strutters attacked the shipyards at Hoboken.
  That the R.N.A.S. bombing programme did not develop further at that time was attributable to a remarkably unselfish act of the Admiralty. It had been hoped that the new No. 3 Wing, based at Luxeuil for strategic bombing, would have been fully equipped with twenty 1 1/2-Strutters and fifteen Short Bombers by July 1st, 1916. But in those critical weeks which preceded the opening of the Battle of the Somme the Royal Flying Corps found itself short, by twelve squadrons, of the number of aeroplanes needed for the operation. General Henderson thought that the smallest possible reinforcement must consist of four fighting squadrons or seventy-two aeroplanes, but a thorough search of all R.F.C. units at home produced twelve aircraft.
  The War Office thereupon appealed to the Admiralty for assistance, and it is to the latter Department’s eternal credit that it recognised the seriousness of the situation and made an immediate and effective response by handing over considerable numbers of 1 1/2-Strutters. By the middle of September, 1916, sixty-two machines had been handed over, and in all seventy-seven were transferred to the R.F.C. The details of the transferred 1 1/2-Strutters are appended. This action by the Admiralty considerably delayed the equipping of No. 3 (Naval) Wing.
  The 1 1/2-Strutter had also been ordered for the R.F.C., and the first contract, for fifty machines, was placed with Ruston, Proctor & Co. about the end of February, 1916. The first of these 1 1/2-Strutters were supplied to No. 70 Squadron, and so urgent was the need for fighting aircraft in France that the squadron went overseas by Flights as machines became available. The first Flight (“A” Flight) went to France on May 24th, 1916, and “B” Flight arrived on June 29th. The third Flight, which arrived on July 30th, was equipped with 1 1/2-Strutters which had been transferred from the R.N.A.S.
  This is perhaps the most appropriate point at which to mention the 1 1/2-Strutter’s armament. As a fighting aircraft it is of great historical importance, for it was the first British aeroplane to go into service equipped with a synchronising gear which made it possible to fire a machine-gun through the revolving airscrew. British experiments with synchronising and interrupter gears had been under way for some considerable time before the first example of the Fokker interrupter gear fell into British hands on April 8th, 1916, and the enemy device neither prompted nor inspired British development of such gears.
  On the 1 1/2-Strutter a single Vickers gun was mounted on top of the engine cowling and fired forward. The machines built for the R.F.C. had the Vickers synchronising gear installed, and it was this type that was used by the first two Flights of No. 70 Squadron. The R.N.A.S. favoured the Scarff-Dibovski synchronising gear, however, and it was standardised on R.N.A.S. 1 1/2-Strutters. The basic idea had been put forward by Lieutenant-Commander V. V. Dibovski of the Imperial Russian Navy in January, 1916, and the mechanism proper was designed by Warrant Officer F. W. Scarff of the Air Department of the Admiralty. The ex-R.N.A.S. 1 1/2-Strutters used by “C” Flight of No. 70 Squadron had the Scarff-Dibovski synchronising gear. Later machines also had the Ross and Sopwith-Kauper gears which, like the Vickers and Scarff-Dibovski gears, were purely mechanical.
  The mounting for the observer’s Lewis gun underwent several changes. The earliest production 1 1/2- Strutters had the Scarff socket and pillar mounting, which was a rather rudimentary affair and allowed only a limited movement of the gun. This was soon superseded by the Nieuport ring-mounting which allowed the gun to be swung in a complete circle around the rear cockpit and enabled the gun to be elevated and lowered. The Nieuport mounting was a rather cumbersome structure, however, and a much improved mounting soon followed. This further product of Warrant Officer Scarff’s inventive genius was the remarkably efficient Scarff No. 2 ring-mounting, which remained in use for over twenty years; its form and appearance are too well-known to need description here.
  The first aeroplanes in the R.F.C. to have the Scarff mounting were the ex-R.N.A.S. Sopwith 1 1/2-Strutters which equipped “C” Flight of No. 70 Squadron. Its worth was instantly recognised, and General Trenchard asked that all R.F.C. 1 1/2-Strutters be fitted with the new gun-mounting. This was done as soon as supplies permitted, and the Scarff ring-mounting was standardised, not only by the R.F.C. and R.N.A.S., but by the Allies as well.
  By virtue of its armament the 1 1/2-Strutter acquired further historical significance, for it was the first aeroplane to be built to what was later known as the two-seat fighter formula. That formula was to endure for nearly a quarter of a century.
  In addition to transferring so many of their Sopwiths to the R.F.C., the R.N.A.S. later provided a squadron to help the R.F.C. on the Somme front. This unit was the famous No. 8 (Naval) Squadron, the equipment of which included a Flight of 1 1/2-Strutters which were supplied by No. 5 Wing. The squadron made its first patrol on November 3rd, 1916, but the 1 1/2-Strutters were soon replaced by Sopwith Pups.
  The 1 1/2-Strutter was not particularly fast at combat heights, nor was it particularly manoeuvrable. In fact, Captain Norman Macmillan has recorded that it was a very stable aeroplane which strongly resisted any sudden change of attitude, and that it required all of a pilot’s strength and skill to put it into a dive. Nevertheless, the 1 1/2-Strutter gave a good account of itself throughout 1916. That it did so was probably to the credit of its double armament, for at the time of its introduction it was rare to find a tractor two-seater fitted with a forward-firing gun.
  Captain W. D. S. Sanday of No. 70 Squadron scored more than one success while flying a 1 1/2-Strutter. On August 6th, 1916, his patrol met a formation of ten bomb-laden enemy machines near Bapaume. The Sopwiths fought the enemy back to their own aerodrome, and forced all the German machines to land, as they had taken off, with their bombs still in their racks. On September 6th, Captain Sanday was flying one of three 1 1/2-Strutters which were making a reconnaissance flight when they were attacked west of Busigny. In the ensuing fight, Sanday shot down one enemy machine in flames, and the Sopwiths beat off all other attacks.
  But by that September, the 1 1/2-Strutter began to be outclassed, and on the 30th of the month, Sir Douglas Haig wrote:
  “Within the last few days the enemy has brought into action on the Somme front a considerable number of fighting aeroplanes which are faster, handier, and capable of attaining a greater height than any at my disposal with the exception of one squadron of single-seater ‘Nieuports’, one of ‘F.E. Rolls-Royce’, and one of ‘Sopwiths’ - the last-mentioned being inferior to the enemy’s new machines in some respects though superior in others.”
  On the day that Sir Douglas Haig wrote these words, No. 45 Squadron completed its equipment with 1 1/2-Strutters. The squadron arrived at Fienvillers on October 15th, 1916, and one week later lost three of its aircraft on an offensive patrol. The only other R.F.C. unit to have the 1 1/2-Strutter was No. 43 Squadron, which did not reach France until January 17th, 1917. The Sopwiths of this squadron carried out several gallant ground attack operations during the Battles of Arras and Messines.
  In the autumn of 1916, production 1 1/2-Strutters began to be fitted with the 130 h.p. Clerget in place of the earlier 110 h.p. version of that engine. The new power plant made only a slight improvement in the machine’s performance, however.
  Replacement of the 1 1/2-Strutter began in July, 1917, and by the end of that month, No. 70 Squadron was completely re-equipped with Sopwith Camels. No. 45 Squadron had its complement of Camels by September 1st, but it was not until October 3rd that No. 43 Squadron was completely re-equipped.
  In the R.N.A.S. the 1 1/2-Strutter gave even longer service, and was very widely used. Mention has already been made of its use as a bomber by the 5th Wing of the R.N.A.S., and that service was primarily responsible for the production of a single-seat version for long-range bombing. The single-seat 1 1/2-Strutter was structurally identical to the two-seat version, but the rear cockpit and gun-ring were completely absent, and the rounded top-decking was continuous from the back of the pilot’s seat down to the tail. Bombs could be carried internally: the bomb compartment was just behind the pilot’s seat, and there were cells for twelve bombs. The Vickers gun was retained, and some of the single-seat 1 1/2-Strutters also had a Lewis gun above the upper wing. This latter gun must have been inaccessible for re-loading in flight, and may have been fitted as a reserve weapon.
  The bomber version was used by the R.N.A.S. 3rd and 5th Wings, and some numbers were also delivered to the R.F.C. In several cases, production batches consisted of a mixture of single-seat and two-seat 1 1/2-Strutters; but official records do not include any references to 1 1/2-Strutter bombers operated by the R.F.C., despite the fact that no fewer than eighty-nine were delivered to that Service. The great majority went to training units, thirteen went to the Middle East, three to Home Defence squadrons, and only one to the B.E.F. in France.
  The type was not used a great deal for Home Defence work. No. 44 Squadron was formed at Hainault Farm with 1 1/2-Strutters as its equipment on July 24th, 1917, but began to receive Camels during the following month.
  A single-seat 1 1/2-Strutter of quite a different kind and apparently intended for Home Defence service was B.762. This machine was flown from what was normally the rear cockpit, which was provided with a faired head-rest for the pilot, and was armed with a pair of Lewis guns on a special mounting immediately in front of the windscreen. The guns pointed upwards at an angle of about 70 degrees. This 1 1/2-Strutter’s serial number falls within a batch allocated to the Southern Aeroplane Repair Depot; this may mean that it was a “home-made” conversion or rebuild, and not a true Service variant.
  As time went on and production gained momentum, the R.F.C. was able to repay part of its debt to the R.N.A.S. by transferring some 1 1/2-Strutters to the latter Service. At least thirty-seven such transfers were made, and it appears that most of the transferred machines retained their original serial numbers.
  The 1 1/2-Strutter was used as a ship-board aeroplane, both with a wheel undercarriage and on rigid skids. By March, 1918, H.M.S. Furious had been fitted with a landing deck abaft the funnel, and her equipment consisted of fourteen two-seat 1 1/2-Strutters and two Sopwith Pups. The landing deck was fitted with an early form of arrester gear, and at a later stage the aircraft on the Furious were fitted with skid undercarriages. On H.M.S. Vindex experiments were also carried out with a 1 1/2-Strutter, N.5601, which had a skid undercarriage: this machine was flown off a special trackway which had two long troughs in which the skids ran.
  Preliminary experiments with rigid skid undercarriages on 1 1/2-Strutters had been made at the Isle of Grain. Tests were also made with a 1 1/2-Strutter which had a hydrovane at the front of its skids, and was also fitted with flotation gear: an inflatable canvas bag was fitted to each lower longeron forward of the wings. Ditching trials with these bags were successful.
  Shortly after the war, a 1 1/2-Strutter was used in experiments at the Isle of Grain with a new form of landing equipment for ship-board aircraft. This device consisted of a long wire jackstay stretched between posts at a height of about 20 feet above the ground. The aircraft was fitted with a hook above the wing which had to engage with a loop of wire hanging from and free to slide along the jackstay. This procedure called for a high degree of piloting skill, and obviously could have found no application on ships, since the motion of the ship would have made the engagement of the loop an impossibility. A few successful “landings” were made with the device at Grain, but it was never developed.
  Sopwith Pups had been flown successfully from short platforms mounted on top of the gun-turrets of capital ships, and it was thought possible that two-seaters might also be able to take off from such sketchy surfaces. The turret platform of the Repulse was lengthened, but the first attempted take-off, made by a 1 1/2-Strutter in March, 1918, ended in failure. Trials were continued on H.M.A.S. Australia, on which a longer platform was built, and a successful take-off was accomplished by Captain F. M. Fox on April 4th, 1918; he was flying a 1 1/2-Strutter with an observer and wireless equipment on board. His achievement was the first take-off made by a two-seat aeroplane from a British warship. After Fox had demonstrated the feasibility of flying a 1 1/2-Strutter from a turret platform it was officially decided to fit extended platforms to the forward turrets of all battle cruisers.
  The 1 1/2-Strutter was used as an anti-submarine patrol aeroplane over home waters at a time when there were no seaplanes available. In April, 1917, R.N.A.S. stations, each with four 1 1/2-Strutters, were opened at Prawle Point, Mullion and Pembroke.
  In the Mediterranean, anti-submarine patrols were also flown by 1 1/2-Strutters based at Otranto. These patrols began in June, 1917, and the 1 1/2-Strutters were chiefly used as stand-by aircraft because they could take off quickly when reports of a sighting of a U-boat were received. One of the Otranto-based Sopwiths scored a success on September 17th, 1917: it dropped a 65-lb delayed-action bomb just ahead of a U-boat, whereupon a large oil patch came to the surface. The U-boat was not again heard by an eight-hour hydrophone patrol.
  Farther east, in the Macedonian theatre of war, the 1 1/2-Strutter was used by the R.N.A.S. units which operated from the islands in the Aegean and from Stavros on the mainland. These were “A” Squadron at Thasos, “B” Squadron at Thermi (on Mitylene), “C” Squadron at Imbros and Mudros, and “D” Squadron at Stavros. To help the R.F.C. against No. 1 Kampfgeschwader, the German mobile bombing squadron which gave so much trouble in Macedonia early in 1917, numbers of R.N.A.S. 1 1/2-Strutters were taken from “C” and “D” Squadrons to form two further units known as “E” and “F” Squadrons. In March 1917, four 1 1/2-Strutters and one Sopwith Triplane were allocated to “E” Squadron, which was sent to Hadzi Junas; there the Sopwiths were combined with B.E.12s and D.H.2s of R.F.C. Squadrons Nos. 17 and 47 to form a unit known as the Composite Fighting Squadron. The second new R.N.A.S. squadron was known as “F” Squadron, and was formed in April 1917. Its equipment consisted of both single-seat and two-seat 1 1/2-Strutters, and it operated first from Amberkoj, where it arrived on April 29th,
The 1 1/2-Strutters of “F” Squadron made many attacks on enemy dumps and camps behind the Dojran front. On May 11th, the squadron moved to Marian for bombing operations on the Struma front. Drama aerodrome, railway stations and dumps provided targets, and a major success was scored on May 25th, when an ammunition dump at Livunovo was destroyed.
  Two days later, five of “F” Squadron’s 1 1/2-Strutters were destroyed in an explosion at Marian. The unit was then merged with “E” Squadron to form a new “F” Squadron which, after re-equipment at Mudros, went to Thasos on June 6th, 1917. On the 17th, “F” Squadron was withdrawn to Mudros; and at the end of July the unit went to Thermi, on the island of Mitylene, for special bombing operations in the Smyrna area. At that time the squadron had five 1 1/2-Strutter single-seat bombers, three of the two-seat fighter type, and a Sopwith Camel. Between August 1st and September 17th, the 1 1/2-Strutters flew a total distance of 13,000 miles on bombing raids which were delivered with telling effect.
  The Sopwith 1 1/2-Strutter was not only used by other nations, but it was also built overseas under licence. France was interested in the type at an early date, and nine of the first 150 machines built for the R.N.A.S. were transferred to our Ally. Other transfers were made later, and included a number of the single-seat bomber version of the 1 1/2-Strutter.
  Production was undertaken in France on a considerable scale, for contemporary reports indicate that 4,500 Sopwith 1 1/2-Strutters were built there. Many of them were fitted with the 110 h.p. Le Rhone engine in place of the standard Clerget. The type was used on the Western Front by a number of French escadrilles for reconnaissance and bombing duties, and some were also used by French units in Macedonia. In accordance with French practice, those 1 1/2-Strutters which were used for reconnaissance work were designated Sopwith 1A.2, and the bombers were known as the B.1 (single-seat) and 1B.2 (two-seat). When it was withdrawn from front-line service with French units the 1 1/2-Strutter was used for training purposes. Many had full dual control and were modified to have the 80 h.p. Le Rhone engine.
  The 1 1/2-Strutter was also used by Belgium and Russia. Eight two-seaters from an Admiralty contract were transferred to Belgium, and Russia received one two-seater and one single-seater. Both countries received further supplies of the type, some of which may have been built in France.
  At least three Belgian squadrons were equipped with 1 1/2-Strutters. When the Belgian 4th Squadron was re-equipped with the Sopwith, one of its members was First-class Sergeant-Pilot Willy Coppens, who was later to become Belgium’s leading fighting pilot. He first flew a 1 1/2-Strutter on April 29th, 1917, and two days later had his first combat on it. That combat came near to being his last, for his machine was then without a forward-firing gun, and he was attacked by four German fighters.
  On July 6th, 1917, King Albert of the Belgians flew over the lines in a Sopwith 1 1/2-Strutter of the Belgian 4th Squadron, piloted by Jacques de Meeus.
  Russia had 1 1/2-Strutters powered by Le Rhone and Clerget engines, and used them for reconnaissance. In the fighting in Northern Russia which followed the revolution, the White Russians operated a few 1 1/2-Strutters. Twenty 1 1/2-Strutters were supplied to the Roumanian government by Britain before the end of the war, and the type was also used by Japan and, in 1919, by Latvia.
  In 1918 the American Expeditionary Force bought a total of 514 French-built Sopwith 1 1/2-Strutters. Most of these were used as trainers at Issoudun, but some were issued to the 90th Aero Squadron for frontline service. One American 1 1/2-Strutter, presumably in Navy service, was fitted with a hydrovane in front of the wheels of the undercarriage.
  Numbers of 1 1/2-Strutters survived the war, and several went on the French Civil Register. At the time of writing, one example of the type is known still to exist: it is the 1 1/2-Strutter which is preserved in the Musee Royal de l’Armee et d’Histoire Militaire in Brussels.


SPECIFICATION
  Weights {lb) and Performance:
Version Two-seater Two-seater Two-seater Single-seater Single-seater
Engine 110 h.p. 130 h.p. 110 h.p. 110 h.p. 130 h.p.
Clerget Clerget Le Rhone Clerget Clerget
No. of Trial Report M.79 D.21 M.125 M.129 D.23
Date of Trial Report December, 1916 November, 1916 July, 1917 August, 1917 November, 1916
Type of airscrew used on trial L.P.710C L.P.710 L.P.710C L.P.710C L.P.710C
Weight empty 1,259 1,305 1,281 1,354 1,316
Military load 160 157 160 320 344
Crew 360 360 360 180 180
Fuel and oil 370 328 404 508 502
Weight loaded 2,149 2,150 2,205 2,362 2,342
Maximum speed (m.p.h.) at
ground level 106 - - - -
4,000 ft 103 - - - -
6,000 ft 101 - - - -
6,500 ft 100-5 100 - - 102
8,000 ft 99 - - - -
10,000 ft 96-5 97-5 103 94 98-5
12,000 ft 92 - - - -
14,000 ft 86 - - - -
m. s. m. s. m. s. m. s. m. s.
Climb to
1,000 ft 1 20 - - - -
2,000 ft 2 40 - - - -
3,000 ft 4 10 - - - -
4,000 ft 5 45 - - - -
5,000 ft 7 45 - - - -
6,000 ft 9 45 - - - -
6,500 ft 10 50 9 10 10 30 14 00 12 40
7,000 ft 11 50 - - - -
8,000 ft 14 25 - - - -
9,000 ft 17 25 - - - -
10,000 ft 20 25 17 50 18 55 26 55 24 35
11,000 ft 23 50 - - - -
12,000 ft 27 40 - - - -
13,000 ft 35 00 - - - -
15,000 ft - 41 55 41 30 - -
Service ceiling (feet) - 15,500 16,000 12,500 13,000
Endurance (hours) 4 1/4 3 3/4 - - -

  Manufacturers: The Sopwith Aviation Co., Ltd., Canbury Park Road, Kingston-on-Thames.
  Other Contractors: The Fairey Aviation Co., Ltd., Hayes, Middlesex. Hooper & Co., Ltd., 77 Kings Road, Chelsea, London, S.W. Mann, Egerton & Co., Ltd., Prince of Wales Road, Norwich. Morgan & Co., Leighton Buzzard. Ruston, Proctor & Co., Ltd., Lincoln. Vickers, Ltd. (Aviation Department), Imperial Court, Basil Street, Knightsbridge, London, S.W. (production at Crayford works). The Wells Aviation Co., Ltd., 30 Whitehead’s Grove, Chelsea, London, S.W.3. Westland Aircraft Works, Yeovil. French Contractors: F. Liore et Olivier, Rue de Villers 46, Levallois-Perret, France. Hanriot et Cie, 84, Avenue des Moulineaux, Billancourt, Seine, France.
  Power: 110 h.p. Clerget 9Z; 130 h.p. Clerget 9Bc; 135 h.p. Clerget 9Ba; 110 h.p. Le Rhone 9J; 130 h.p. Le Rhone 9Jby; 80 h.p. Le Rhone 9C.
  Dimensions: Span: 33 ft 6 in. Length: 25 ft 3 in. Height: 10 ft 3 in. Chord: 5 ft 6 in. Gap: 5 ft 4 3/4 in. Stagger: 2 ft. Dihedral: 2° 23'. Incidence: 2° 10'. Span of tail: 13 ft 6 in. Airscrew diameter: 8 ft 11-9 in.
  Areas: Wings: 346 sq ft. Ailerons: each 13 sq ft, total 52 sq ft. Tailplane: 35-5 sq ft. Elevators: 21-5 sq ft. Fin: 3-5 sq ft. Rudder: 7-25 sq ft.
  Tankage: Petrol: 40 gallons. Oil: 9-5 gallons.
  Armament: Two-seat reconnaissance version: one fixed forward-firing Vickers machine-gun mounted centrally on top of the fuselage, synchronised to fire through the airscrew by means of Vickers, Scarff-Dibovski, Ross or Sopwith-Kauper synchronising gear; one free Lewis machine-gun on pillar-mounting, Nieuport ring-mounting or Scarff ring-mounting. Twelve le Pecq bombs could be carried; and on anti-submarine patrol the bomb-load consisted of two 65-lb bombs. Single-seat bomber version: one fixed Vickers machine-gun as on two- seater; four 56-lb bombs, or equivalent weight of lighter bombs.
  At least one Home Defence single-seat 1 1/2-Strutter, which was flown from what was normally the rear cockpit, had a pair of upward-firing Lewis guns immediately in front of the windscreen.

Serial Numbers:
Serial Nos. Built by For Version
3686 Sopwith R.N.A.S. Two-seat prototype.
7762-7811 Ruston, Proctor R.F.C. Two-seat fighter
9376-9425 Sopwith R.N.A.S. Two-seat fighter
9651-9750 Sopwith, under Contract No. C.P.104237/16 R.N.A.S. Mixed: 65 were two-seaters, 35 single-seat bombers
9892-9897 Sopwith R.N.A.S. Two-seat fighter
A.377-A.386 Sopwith R.F.C. Two-seat fighter
A.878-A.897 Sopwith - -
A.954-A.1053 Fairey R.F.C. Two-seat fighter
A.1054-A.1153 Vickers R.F.C. Two-seat fighter
A.1511-A.1560 Westland R.F.C. Two-seat fighter
A.1902-A.1931 Sopwith R.F.C. Two-seat fighter
A.2381-A.2430 Ruston, Proctor R.F.C. Two-seat fighter
A.2983-A.2991 Sopwith R.F.C. Two-seat fighter
A.5238-A.5337 Wells R.F.C. Two-seat fighter
A.5950-A.6149 Morgan R.F.C. Some were single-seat bombers
A.6901-A.7000 Hooper R.F.C. Two-seat fighter
A.8141-A.8340 Ruston, Proctor R.F.C. Two-seat fighter
A.8744-A.8793 Vickers R.F.C. Two-seat fighter
B.2551-B.2600 Ruston, Proctor R.F.C. Two-seat fighter
N.5080-N.5179 Sopwith R.N.A.S. N.5080-N.5087 and N.5090-N.5119 were two-seaters; remainder single-seaters
N.5200-N.5219 Mann, Egerton R.N.A.S. Single-seat bombers
N.5220-N.5249 Mann, Egerton R.N.A.S. Two-seat fighter
N.5500-N.5549 Sopwith R.N.A.S. Only N.5500-N.5537 were built; all were single-seat bombers
N.5550-N.5559 Sopwith R.N.A.S. Single-seat bombers
N.5600-N.5624 Westland R.N.A.S. N.5600-N.5604 were single-seat bombers, remainder two-seaters
N.5630-N.5654 Mann, Egerton R.N.A.S. Two-seat fighter

  Service Use: Western Front: R.F.C. Squadrons Nos. 43, 45 and 70; R.N.A.S. Squadrons Nos. 5 and 8; No. 3 Wing, R.N.A.S.; French Escadrilles Nos. 13, 24, 28, 29, 54, 61, 66, in, 129, 210, 221, 222, 226; Belgian Flying Corps Squadrons Nos. 2, 3 and 4; United States Air Service 88th, 90th and 99th Aero Squadrons. Eastern Front: used by the Russians. Macedonia: R.N.A.S. “A” Squadron, Thasos; “B” Squadron, Thermi (Mitylene); “C” Squadron, Imbros and Mudros; “D” Squadron, Stavros; “E” Squadron, as part of Composite Fighting Squadron at Hadzi Junas; “F” Squadron, Amberkoj, later at Marian, Thasos, Mudros and Thermi. Also used by a French unit operating from Florina. Home Defence: R.F.C. Squadrons Nos. 37, 44. Coastal Patrol: R.N.A.S. Stations at Great Yarmouth, Mullion, Pembroke, Prawle Point. Aircraft carriers Furious, Vindex, Argus. Battleships H.M.A.S. Australia, Queen Elizabeth, Barham. Mediterranean: R.N.A.S. Station, Otranto. Training: training squadrons at Eastbourne and Shawbury; No. 31 Training Squadron, Wyton; R.N.A.S. Stations at Cranwell, Dover, Manston. Flight Observers’ School, Leysdown. American Expeditionary Force 3rd Instruction Centre, Issoudun.
  Production and Allocation: Serial numbers indicate that at least 1,513 Sopwith 1 1/2-Strutters were built in Britain for the R.F.C. and R.N.A.S. Further machines may have been built for France and Russia, and reports have stated that 4,500 were built under licence in France. The R.F.C. took delivery of 607 two-seat 1 1/2-Strutters and eighty-nine of the bomber version: of these, seventy-seven were transfers from R.N.A.S. production. Also from the machines produced for the R.N.A.S., sixty-one were transferred to France, eight to Belgium and two to Russia. Of later production for the R.F.C. at least thirty-seven were transferred to the R.N.A.S. Of the R.F.C.’s 1 1/2-Strutters, 346 two-seaters and one single-seater went to the squadrons in France, thirteen single-seaters to the Middle East Brigade, fifty-six two-seaters and three single-seaters to Home Defence units, and 205 two-seaters and seventy-two single-seaters to Training Units. On October 31st, 1918, the R.A.F. had 137 two-seat 1 1/2-Strutters and thirty-four single-seaters on charge. Thirty-six two-seaters and two single-seaters were with the Grand Fleet; three two-seaters and one single-seater were with the 5th Group; three single-seaters were in Egypt; eleven two-seaters and two single-seaters were in the Mediterranean area; fifty-eight two-seaters and ten single-seaters were at various aerodromes in the United Kingdom; eleven two-seaters were at Aeroplane Repair Depots; and eighteen two-seaters and sixteen single-seaters were in store. The American Expeditionary Force bought 514 Sopwith 1 1/2-Strutters from France in February and May, 1918: 236 had the 130 h.p. Le Rhone engine, 148 had the 130 h.p. Clerget, and the remainder had the 135 h.p. Clerget. Twenty 1 1/2-Strutters were supplied to the Roumanian Government, and some went to Japan.
  Notes on Individual Machines: R.N.A.S. transfers to R.F.C.: 9381, 9386-9389, 9391-9393, 9403, 9405, 9406, 9409, 9412, 9418, 9421, 9424, 9653, 9656, 9659, 9662, 9665, 9668, 9669, 9671, 9673-9691, 9693-9707, 9710, 9713, 9714, 9716, 9719, 9721, 9725, 9728, 9729, 9731, 9734, 9736-9738, 9740, 9743, 9745, 9746, 9749. R.F.C. transfers to R.N.A.S.: A.1148, A.5253, A.5260-A.5262, A.5951, A.5952, A.5982-A.6000, A.6006, A.6910-A.6913, A.6917-A.6922, A.6966, A.6985-A.6990, A.8204, A.8288, B.2551.Transfers to France: 9413, 9651, 9655, 9657, 9661, 9664, 9666, 9720, 9742, 9892-9897, N.5091, N.5092, N.5094, N.5095, N.5097, N.5098, N.5100, N.5101, N.5103, N.5104, N.5113, N.5115, N.5116, N.5118, N.5122, N.5123, N.5125, N.5146, N.5157, N.5158, N.5160, N.5502, N.5507, N.5511, N.5514, N.5523. Transfers to Belgium: N.5235-N.5242. Transfers to Russia: N.5219, N.5244. Presentation aircraft: 9378: New Zealand No. 1. 9383: Britons in Japan No. 1. 9395: Tientsin Britons No. 1. 9401: “Poverty Bay”, New Zealand No. 2. 9405: Britons in Egypt No. 1. 9423: Peking Britons No. 1. 9654: Rio de Janeiro Britons No. 1. 9667: Tientsin Britons No. 2. 9722: Sao Paulo Britons No. 1. 9739: Britons in Egypt No. 2. 9744: Britons in Italy No. I. N.5084: Sao Paulo Britons No. 2. Sopwith 1 1/2-Strutters used by No. 5 Squadron, R.N.A.S.: 9378, 9383, 9396 (bombed Zeppelin sheds at Cognelee August 25th, 1916; forced to land in Holland and interned), 9397, N.5514 (“B-3”), N.5531. Used by No. 3 Wing, R.N.A.S.: 9410, 9669, 9722, 9742, N.5089, N.5091, N.5098, N.5107, N.5115, N.5116, N.5171, N.5173, N.5174, N.5512. Used by R.N.A.S., Mudros: N.5086, N.5224, N.5517, N.5527. Used by No. 43 Squadron, R.F.C.: A.960, A.961, A.970, A.1010, A.x too (“C.5”), A.1108 (shot down by Manfred von Richthofen), A.2388, A.2401. Used by No. 45 Squadron, R.F.C.: 7774, 7775, 7792 (flown by Lt. F. T. Courtney; crashed April 4th, 1917), 7800, A.1075, A.1077, A.1083, A.1084, A.1095, A.2381, A.2382, A.2385, A.8260, B.2576, B.2583. Used by No. 70 Squadron R.F.C.: 7763, A.380, A.884, A.954, A.956, A.957, A.958, A.976, A.981, A.994, A.g95, A.996, A.997, A.1002, A.1069, A.1514, A.1902, A.1925, A.2983, A.2984, A.2986, A.8172, A.8213. Other machines: 9420: interned in Holland September 17th, 1916. 9422: R.N.A.S., Dover. A.6006: used on H.M.S. Queen Elizabeth. A.6987: skid undercarriage, modified wing-bracing. B.762: single-seat conversion for Home Defence duties; twin upward-firing Lewis guns. B.2591: flown at Eastbourne. N.5119: “F” Squadron, R.N.A.S., Stavros. N.5503: R.N.A.S., Dover. N.5601: H.M.S. Vindex. N.5630 and N.5632: R.N.A.S., Cranwell.
  Costs:
   Airframe without engine, instruments and guns £842 6s.
   Engines:
   130 h.p. Clerget £907 10s.
   110 h.p. Le Rhone £771 10s.

H.King Armament of British Aircraft (Putnam)

1 1/2 Strutter. Although justly remembered as the archetype of the classic two-seat fighter (pilot with fixed gun, gunner with free gun), this biplane of 1915/16 was also constructed as a specialised bomber and as a 'ship's aeroplane'. In all three forms the armament differed. While the fighter and bomber had a fixed Vickers gun, the third variant did not. The prototype and some production aircraft were flown without armament, the reason in part being a shortage of Vickers guns. While at least one early specimen had the gun mounted on the port upper longeron, with the breech casing lying under the built-up coaming of the cockpit, on all standard production fighters and bombers thereafter the gun was mounted on the centre line of the fuselage immediately ahead of the pilot, with the firing lever projecting from the gun above the control column. The Sopwith patented padded windscreen was fitted, and plain open or ring-and-bead sights were mounted on the gun. The ammunition was fed from the right, and a metal plate on the left, forward of the feed block, served to prevent the canvas belt from twisting in the slipstream before entering the protection of the fuselage. On some early examples the rear of the gun was partly faired. The first machines for the RFC (A and B Flights of No.70 Squadron) had gun-synchronising gear of the Vickers type, but C Flight of the same unit had aircraft intended for the RNAS and fitted with the Scarff-Dibovsky gear developed for, and standardised by, that Service. Gears of the Ross and Sopwith-Kauper types were also fitted. The advantages of the Vickers gun, with its continuous belt feed, over the drum-fed Lewis, which demanded the breaking-off of an engagement for the changing of drums, was quickly apparent.
   That the Scarff No.2 ring-mounting for the Lew is gun was developed with the assistance of the Sopwith company is not generally known, and it is with this most famous of all aircraft gun mountings that the 1 1/2 Strutter is most intimately associated. Early examples, however, had either a Strange cranked pillar mounting or a ring-mounting of the French Nieuport type. The Scarff No.2 mounting was first introduced in the ex-RNAS aircraft of C Flight. No.70 Squadron, already mentioned in connection with the Scarff-Dibovsky gear. It was mourned directly on the top longerons, and thus below the fuselage top line, and its diameter was slightly greater than the fuselage width. Standard ammunition provision on the 1 1/2 Strutter two-seater was 300 rounds in a fabric belt for the Vickers gun and five double drums for the Lewis gun. On one aircraft of B Flight, No.70 Squadron, an auxiliary armament of an automatic pistol with oversize magazine was attached to the starboard undercarriage struts to fire outside the airscrew arc. On certain Home Defence aircraft, the Vickers gun was dismounted, the front cockpit was faired over, the pilot was moved to the rear and a Lewis gun was mounted over the top wing to fire above the airscrew and obviate the risk of using 'special' ammunition in the synchronized gun. One aircraft had two upward-firing Lewis guns mounted forward of the cockpit in a special installation, and another carried the same armament on a twin mounting of Foster type.
   Apart from its Scarff ring-mounting and Sopwith padded screen, the 1 1/2 Strutter was notable also for its tailplane incidence-adjusting gear, a primary purpose of which was to compensate for gunners of different weights. For this aeroplane, also, Sopwith developed a special gunners seat, capable of all-round movement about an eccentric pivot on a fixed stand. Means were provided for automatically locking the seat to the stand when the seat was occupied and for unlocking the seat when it was relieved of the gunner's weight. A wooden frame carried a vertical pivot having a toothed ring which was pressed, by the weight of the gunner acting against a spring, into engagement with a toothed ring carried by a fixed socket supported by legs. The engagement between the teeth served to fix the seat in the desired position, but disengagement automatically took place under the action of the spring when the gunner raised himself, and the seat could then be freely rotated in the socket.
   No fighting aeroplane ever introduced as many novel armament features as this Sopwith two-seater.
   Bomb rails were sometimes fitted beneath the lower wings and/or fuselage of 1 1/2 Strutter two-seaters, and possible loads were four or eight 20-lb or two 65-lb. The potential of these aircraft as long-range bombers was quickly recognised by the RNAS; indeed the 1 1/2 Strutter had been originally designed for bombing and has a place in history as one of the first truly 'strategic' bombers. A specialised single-seat bomber type was developed, and this carried its bombs internally in a compartment which took the place of the gunner's cockpit. Official rigging notes indicate that the rear flying wires on bombers were shorter than on fighters. The standard load was four 50-lb or 65-lb bombs, horizontally stowed. The four trapdoors beneath the bomb compartment were opened by the weight of the falling bombs and were closed again by shock-absorber cord. Two small inspection and access panels were let in to each side of the bomb compartment. On the single-seat bomber, 500 rounds were provided for the Vickers gun. Occasionally a Lewis gun was fixed to fire over the top wing of bombers as auxiliary armament, but the drum for this could not be changed in flight. The 'Sopwith Bomber (Clerget)' was declared obsolete in an Air Ministry Order of 1921.

O.Thetford British Naval Aircraft since 1912 (Putnam)

Sopwith 1 1/2 Strutter

   The claims of the Sopwith 1 1/2 Strutter to historical fame are many. It was, of course, the first of the Sopwith breed to achieve widespread use as a fighting aeroplane and hence the precursor of a justly renowned series. In addition to this it was the first British aeroplane to enter service already equipped with a synchronising gear, enabling the fixed front gun to fire between the revolving blades of the airscrew, and also the first two-seater which gave the pilot a chance to use his gun effectively as well as the observer. It thus established what came to be a classic formula, that of the two-seat fighter, later exemplified in the Bristol Fighter and the Hawker Demon.
   Nor did the 1 1/2 Strutter's pioneering tendencies end here. In 1916, with the 3rd Wing of the RNAS at Luxeuil. 1 1/2 Strutters became the first British aircraft ever to take part in bombing raids of an avowedly strategic nature, attacking German industrial centres and providing, as it were, a prelude to the heavier blows struck later by the squadrons of the RAF's Independent Force. Finally, in the sphere of shipboard flying, it was a 1 1/2 Strutter that became the first two-seater to take off from a British warship, in April 1918.
   The Admiralty had from the earliest beginnings of the RNAS shown interest in the products of the Sopwith Company, and it was therefore only logical that the 1 1/2 Strutter should be first ordered for naval service, though it later entered the RFC as well. The prototype (No.3686) was completed at the end of 1915, and first deliveries of RNAS Strutters began early in 1916, against an Admiralty contract for 150. Some of the first to enter service equipped part of No.5 Wing at Coudekerque in April 1916. NO.5 Wing was formed in March 1916 for long-range bombing duties and was equipped primarily with Caudrons and Farmans. The 1 1/2 Strutters were able to provide a welcome escort, as well as operating in the bombing role themselves. As related in the narrative on the Caudron G.4, a 1 1/2 Strutter was on 2 August 1916 used to control a No.5 Wing bombing formation by firing Very lights, a sort of forerunner of the master bomber technique of the Second World War. A few days later, on 9 August, two of NO.5 Wing's 1 1/2 Strutters flown by F/Sub-Lts R H Collet and D E Harkness made bombing attacks on the Zeppelin sheds at Evere and Berchem Ste Agathe; another attack followed on 25 August, this time on the sheds at Cognelee. Subsequently the 1 1/2 Strutters of No.5 Wing participated in many important raids on enemy aerodromes and ammunition dumps, as well as naval targets such as U-boat bases and the Tirpitz battery.
   Meanwhile, plans for the establishment of NO.3 Wing. RNAS (which was to have received 20 1 1/2 Strutters by 1 July 1916). had been delayed due to the Admiralty's agreement to forgo its Strutters in favour of the RFC, which was desperately short of aircraft with which to fight the Battle of the Somme. Eventually No.3 Wing's 1 1/2 Strutters started their raids in October 1916 and, though severely hampered by winter weather conditions, bombed industrial targets at Hagendingen, Oberndorf, Dillingen and other towns in the Saar where the Admiralty believed steel for U-boats was being manufactured in large quantities. It is interesting to note that No.3 Wing's base at Luxeuil was close to Belfort. from whence the RNAS Avros had taken off in November 1914 to raid Friedrichshafen.
   Two distinct versions of the 1 1/2 Strutter were supplied to the RNAS, where the type was officially known as the Sopwith Type 9700. As well as the normal two-seater, the RNAS used a single-seat bomber without the rear cockpit, with provision for 12 bombs stowed internally. It is recorded that, of some 550 1 1/2 Strutters supplied to the RNAS, about 420 were two-seaters and the remainder single-seaters.
   Although by 1917 the 1 1/2 Strutter was outclassed as a fighting aircraft on the Western Front, it continued to give extensive service with the RNAS in other theatres of war. The RNAS was, in fact, the only service to operate the type outside France. In Macedonia, particularly, the naval Strutters saw a lot of action in bombing raids between April and September 1917, when they hit targets such as aerodromes, ammunition dumps and railway communications behind the enemy lines on the Struma.
   The Sopwith 1 1/2 Strutter's versatility extended also to anti-submarine patrols, both in home waters and in the Mediterranean area. The home-based patrols started in April 1917 and those in the Mediterranean in June 1917. On 17 September 1917 a 1 1/2 Strutter based at Otranto claimed the sinking of a U-boat by attacking it with a 65 lb delayed-action bomb.
   At the Armistice some 170 Sopwith 1 1/2 Strutters remained in service with the RAF and nearly 40 of these were at sea with the Grand Fleet. Indeed, when, in March 1918, HMS Furious was made the flagship of the Flying Squadron of the Grand Fleet her complement included 14 1 1/2 Strutters. For deck flying the life Strutter was used both with the normal wheeled undercarriage and with a special skid undercarriage first developed in trials at the Isle of Grain: the latter version usually had a hydrovane mounted at the front end of the skids to prevent the aircraft nosing over if forced into the sea. This device. as well as the inflatable air-bags located either side of the engine nacelle, remained a feature of naval aircraft until about 1923, when flotation equipment was mounted inside the rear fuselage instead.
   Numerous experiments in deck-flying were made with 1 1/2 Strutters. One aircraft (N5601) fitted with skids was flown off a railed deck aboard HMS Vindex, and the first successful landing aboard HMS Argus using the early form of deck arrester gear was made by Wg Cdr Bell-Davies, Vc, in F2211 on 1 October 1918. A further development of 1918 was the introduction of 1 1/2 Strutters for two-seat reconnaissance duties aboard capital ships. This involved flying off a short platform mounted above the forward gun turret and became standard practice aboard battle cruisers after the first successful take-off had been achieved from the Australian warship HMAS Australia by Capt F M Fox on 4 April 1918, carrying an observer and full wireless equipment.

UNITS ALLOCATED
   Nos.2, 4, 5, 7 and 8 Squadrons, RNAS (Western Front); Maccdonian units: 'A' Squadron (Thasos). 'B' Squadron (later No.23 (Naval)) (Mitylene). 'C' Squadron (later No.20 (Naval)) (Imbros and Mudros). 'D' Squadron (Stavros). 'E' Squadron (Hadzi Junas). 'F' Squadron (Amberkoj). 'G' Squadron (Mudros) and 'Z' Squadron (Thasos). NO.225 Squadron (Italy). RNAS coastal air stations at Dover, Great Yarmouth, Mullion, Otranto, Pembroke and Prawle Point. RNAS training schools at Cranwell and Manston. Aircraft-carriers: Argus and Furious. Battleships: Australia, Barham. Courageous, Glorious, Indomitable, Inflexible, Malaya, Queen Elizabeth, Renown, Repulse, Valiant, and Warspite. Seaplane carriers: Campania, Vindex and Vindictive.

TECHNICAL DATA (1 1/2 STRUTTER)
   Description: Single-seat bomber, or two-seat bomber, fighting and reconnaissance aircraft for shore-based or carrier-borne operations. Wooden structure, fabric covered.
   Manufacturers: Sopwith Aviation Co Ltd, Kingston-on-Thames (Nos.9376 to 9425, 9651 to 9750, 9892 to 9897, N5080 to 5179, and N5500 to 5537) Sub-contracted by: Mann, Egerton & Co Ltd, Norwich (N5200 to 5219, N5220 to 5249 and N5630 to 5654) and Westland Aircraft. Yeovi1 (N5600 to 5624). Also 70 French-built 11/2 Strutters converted for ship-board flying in 1918 and serialled F2210-2229 and F7547-7596.
   Power Plant: One 110 hp or 130 hp Clerget.
   Dimensions: Span, 33 ft 6 in. Length, 25 ft 3 in. Height. 10 ft 3 in. Wing area, 346 sq ft.
   Weights (two-seater with 110 hp Clerget): Empty, 1,259 lb. Loaded, 2,149 lb. (single-seater with 130 hp C1erget): Empty, 1,316 lb.
   Performance (two-seater with 110 hp Clerget): Maximum speed, 106 mph at sea level; 92 mph at 12,000 ft. Climb, 1 min 20 sec to 1,000 ft; 10 min 50 sec to 6,500 ft; 20 min 25 sec to 1,000 ft. Endurance, 4 1/2 hr. (Single-seater with 130 hp C1erget): Maximum speed, 102 mph at 6,500 ft. Climb, 12 min 40 sec to 6,500 ft; 24 min 35 sec to 10,000 ft. Service ceiling, 13,000 ft.
   Armament (single-seat bomber): One Vickers machine-gun forward and four 65 lb bombs. (Two-seater): One Vickers machine-gun forward and one Lewis machine-gun aft. Two 65 lb bombs for anti-submarine patrol.

J.Davilla, A.Soltan French Aircraft of the First World War (Flying Machines)

Sopwith 1 1/2 Strutter (Sop 1 A2, 1 B1, and 1 B2)

  The Aviation Militaire faced a dual crisis in 1916. The army cooperation escadrilles were equipped with ineffective Caudron G.4s and Farman F.40s, while the bomber escadrilles were still using obsolescent M.F.11s and Voisin 5s. French-built replacements for both categories were planned, but these would not become available until mid-1917. What was needed was a proven type that would be immediately available for mass production and fill the gap until more modern types could enter service.
  The French decided to build British Sopwith 1 1/2 Strutters under license until more sophisticated types, such as the Breguet 14 A2s and B2s, could enter front-line service. While waiting for full-scale production to begin, the French acquired nine single-seat and two-seat examples of the Sopwiths from No.3 Wing RNAS. The first was a two-seater with serial number 9413. The other eight were single-seat bombers with serials 9651, 9655, 9657, 9661, 9664, 9666, 9720, and 9742.
  French production was, yet again, to fall far behind the optimistic projections of the manufacturers. These delays may have had more to do with national pride than any major flaws in the aircraft or manufacturing process. The French claimed to have found numerous deficiencies in the design and insisted that it was structurally unsafe. The latter opinion was based on an incident in February 1917 when a bomber flown by a French pilot disintegrated in mid-air. The British felt that the machine had been over-stressed by the pilot; the French believed structural failure was to blame. Since the type was now being built by the French, it is not surprising that the modifications were introduced, causing further production delays. A GQG memo dated 22 November 1916 reported that tests of the French-built 1 1/2 Strutters had been completed. The upper wings could withstand a weight of 5,680 kg with a load coefficient of 7.25. These results were "comparable to those attained by those aircraft built by the English." The pilots were warned that, although these tolerances were acceptable for an army cooperation plane, they were unacceptable for fighters. The message was clearly given that the Sopwith pilots were not to treat their new machines as fighters.
  The engines used were the 135-hp Clerget 9Ba or Bb, 145-hp Clerget 9Bc, or 135-hp Le Rhone 9Jby. Performance data is given below. The STAe designation was Sop. 1 A2 for the reconnaissance machine and Sop 1 B1 or B2 for the bomber.
  A major modification to the 1 1/2 Strutter was the fitting of a smaller empennage. This resulted in improved performance, as noted below. It is not known how many of the modified 1 1/2 Strutters were built, but while the modified Sopwiths had a superior performance at low altitude, at high altitude they were less effective than the standard model.
  A total of approximately 4,200 Sopwiths were built in France by Amiot, Bessoneau, Darracq, Liore et Oliver, Hanriot, Sarazin, S.E.A., and R.E.P. Floatplane versions of the Sopwith 1 1/2 Strutter were built by Hanriot. A total of 17 floatplane versions of the Sopwith 1 1/2 Strutter were delivered between January and September 1917.


Operational Service

Army Cooperation

  There seems to have been a tremendous amount of excitement on the part of the army cooperation escadrilles about receiving the new planes. First priority was given to reconnaissance units, then fighter escadrilles (to use as reconnaissance planes), followed by artillery aviation units. The fighter and artillery escadrilles were to receive either four Sopwith 1 1/2 Strutters or Morane Saulnier Type Ps, and the Sopwiths were to be given to only the best pilots in each army cooperation escadrille. The 1 1/2 Strutters seemed to have performed well, although a GQG memo dated 30 August 1917 called for the undercarriage axle to be strengthened.
  The Sopwiths manufactured in France did not become available until the spring of 1917, by which time the type was obsolescent. By 1 August 1917 there were 142 Sopwith 1 B1 and B2 and 243 Sopwith 1 A2 aircraft in service. Eighteen reconnaissance escadrilles used the Sopwith P/2 1A2s.
  By late 1917 the appearance of the Breguet 14, Salmson 2, and SPAD 11 permitted the units at last to receive more modern equipment.

Artillery Cooperation Escadrilles

  Forty-one artillery escadrilles used the Sopwith 1 1/2 1 A2s.

Bombing

  The Sopwith 1 B1s and 1 B2s were supplied to 11 bomber units in the spring of 1917. Two Farman units, F 29 and MF 123, received Sopwiths in September 1916. A Caudron escadrille, C 66, was re-equipped with 1 1/2 Strutters in 1917. A single escadrille that used the deficient P.S.7 bombers, PS 128, finally received Sopwiths in July 1917. Three Voisin 8 units reequipped with Sopwiths: VB 107, VB 108, and VC 111. Finally, four new escadrilles were formed on Sopwiths in mid-1917 - SOP 129, 131, 132, and 134. These escadrilles were assigned these Groupes d'Bombardement:
   GB 1: SOP 66 and SOP 111.
   GB 3: SOP 29, SOP 107, SOP 108, SOP 128, and SOP 129.
   GB 4: SOP 123, SOP 131, SOP 132, and SOP 134.
  GB 1 was the first Groupe d'Bombardement to receive the Sopwith 1 1/2 Strutters. GB 1 had two Voisin units and a single Caproni escadrille, which gave it a limited ability to undertake daylight bombing. The Sopwiths of SOP 66 and SOP 111 restored that capability. Both were equipped with both the single-seat (1 B1) and two-seat bomber versions (1 B2). The latter provided fighter escort for the single-seat bombers, which carried no defensive armament. In the 1 B1 variant the rear gunner's compartment was deleted to permit the internal storage of bombs. They were dropped through four bomb bay doors in the floor of the aircraft.
  SOP 66 and 111 were active over the Aisne front in April 1917, bombing barracks, train stations, and marshaling yards. During these early raids it was common for several attacking aircraft to turn back, reportedly due to engine trouble. In May these attacks continued with escort provided by SPAD 7s. June was also a busy month for the units but, again, many aircraft returned due to mechanical difficulties; on 7th June 50 percent of the attacking force was forced to abort a bombing mission. Daytime attacks continued against train stations in July but now the Sopwiths were also being used for night missions. On 12 August SOP 66 and 111 were detached from GB 1 to serve on the Verdun front, assigned to support the troops who would be participating in that offensive. Aerial activity intensified as the date of the battle approached. The Sopwiths bombed train stations and camps along the front and encounters with German fighters occurred frequently. Night attacks were coordinated with the daylight raids so that German camps could be attacked around the clock. In September Sopwiths accompanied Voisin 8s on night missions. Attacks were launched against Frankfurt, but because the Sopwith bombers did not carry a second crew member to do the navigating, they often had difficulty finding the target, especially in bad weather. By 6 October both SOP 66 and 111 were re-equipped with Breguet 14 bombers.
  GB 3, based at Cambrai, received two Sopwith escadrilles, SOP 107 and 108, in June/July 1917. From June through August the units usually had only between six and ten aircraft because of combat attrition and equipment failure. Frequently the single- and two-seat versions of the 1 1/2 Strutters would fly in mixed formation with the two-seaters doing the navigating and providing air cover. The mechanics of GB 3 found the supply and performance of the engines were adequate; however, the airframes were too fragile. Furthermore, the bomb load was too small to do much damage. GB 3 moved from Cambrai to Laon at the beginning of August and from this new base bombed train stations at Roules and targets near Houthulst. PS 128 retired its P.S.7 bombers and received Sopwiths by September. All three Sopwith escadrilles continued attacks on train stations in the vicinity of Cambrai. In October SOP 108 was detached to GB 1; the other two units continued attacks on train stations. SOP 128 switched to Breguet 14s in November, thus leaving SOP 127 the sole Sopwith 1 1/2 Strutter unit attached to GB 3. SOP 127 continued to fly sorties until January 1918 when it, too, was equipped with the new Breguet 14s.
  GB 4 received Sopwith 1 1/2 Strutters in March 1917 when F 29 and 123 converted to the type. In April both escadrilles concentrated on targets at Colmar and in May also attacked Sieren and the airfield at Habsheim. GB 4 continued the practice of sending out mixed formations of single- and two-seat Sopwiths. Beginning on 11 July GB 4's units began a series of attacks on German airfields that continued during August. GB 4 was reinforced that month when SOP 129 joined the group.
  Reinforced by SOP 129, both SOP 29 and 123 staged a large number of raids in September. French records claim that aircraft of GB 4 attacked German airship L.45 on 20 September; German sources, however, do not support this assertion. Raids on train stations continued for the remainder of the month.
  November was to be an even busier month, with the units attempting to complete as many sorties as possible before winter weather brought an end to operations. In December depots and airfields were bombed. SOP 132 and SOP 134 joined GB 4 in January 1918, thus raising the number of Sopwith 1 1/2 Strutter escadrilles to six. GB 4 moved to Luxeuil in mid-January. Gradually, however, the Sopwith units began to receive Breguet 14s and between January and April they frequently flew mixed formations of Sopwiths and Breguets. Targets attacked in January and February included Baden, Wurttemberg, the Mauser factory at Oberndorff, the gunpowder factory at Rottweil, the poison gas factory at Ludwigshafen, and airfields. By March the Sopwiths had been withdrawn from service and GB 4 became an all-Breguet 14 unit.
  France's Aviation Maritime acquired several 1 1/2 Strutters from the Aviation Militaire. Apparently four of them (probably with floats) were assigned to the Centre de Corfu and it is likely that others were assigned to naval bases. Floatplane versions of the Sopwith 1 1/2 Strutter were built by Hanriot. A total of 17 floatplane versions of the Sopwith 1 1/2 Strutter were delivered from January to September 1917. Postwar, some of these planes were initially assigned to the naval base at Saint Raphael as part of escadrille AR 2. It was obvious that the machines were too obsolescent to form an operational unit but they proved to be useful for training. The Sopwiths were apparently easier to fly than the Salmson 2s and thus became the first aircraft to be assigned to the carrier Bearn in October 1920. The Sopwiths were replaced by Breguet 14s in 1922.


Foreign Service

Belgium
  The Belgian air service purchased a number of Sopwith 1 1/2 Strutters, at least three of them French-built machines. They were assigned to the 2nd, 3rd, and 4th Squadrons from 1916 through 1917. They were withdrawn from operational squadrons in October 1921.

Brazil
  Three French-built Sopwith 1 1/2 Strutters were sent to Brazil in 1918. They were used by the Escola de Aviacao Militar for liaison and army cooperation. They had serial numbers 3061, 3514, and 3633.

Japan
  In 1917 Japan purchased a number of Sopwith 1 1/2 Strutters built by the Liore et Olivier firm. The army arsenals at Tokyo built 18 1 1/2 Strutters under license.
Netherlands
  A single French-built 1 1/2 Strutter was interned on 22 April 1917. It had been built by Hanriot and carried serial number 115. It is believed that it was assigned to SOP 111. It was given the Dutch serial LA-45, changed to S-701 in 1918.

Russia/Soviet Union
  Although most of the Sopwith 1 1/2 Strutters used by the Russian air service and the RKKVF (Worker's and Peasant's Red Air Fleet) came from England, a few were license-built French versions. The Siberian Air Fleet of Admiral Kolchak had six 1 1/2 Strutters on strength in 1919. The Siberian Air Fleet of the Far Eastern Republic had three 1 1/2 Strutters in 1920; they had serial numbers 5, 6, and 7.

Ukraine
  A single Sopwith 1 A2 was obtained by the Ukrainians (presumably from Russia) in 1918. It carried serial number 1136.

United States
  The Sopwith bomber had been the primary French day bomber for almost exactly one year, but as the Breguet 14s became available the French supplied the older Sopwiths to the American air service. The United States purchased 514 1 1/2 Strutters in the spring of 1918. A total of 384 reconnaissance versions and 130 single-seat bombers were obtained. The reconnaissance (A2) machines had either 150-hp Le Rhone 9Jby engines (236 examples) or the 130-hp Clerget 9Bc (148 examples). The single-seat bomber version had a 135-hp Clerget 9Ba (130 examples). Both versions were assigned to the 19th, 88th, and 99th Aero Squadrons, which were posted to the 4th, 3rd, and 5th Corps Observation Groups respectively. All the groups were assigned to the 1st Army. Apparently, none of the Sopwith bombers were assigned to the day bombardment groups. The Sopwiths were intensely disliked by the Americans, who felt they were obsolete and underpowered. They were quickly replaced by more modern types.
  The U.S. Navy purchased at least four Sopwith 1 1/2 Strutters directly from France. These had been built under license by the Hanriot firm. The only modifications to them was the addition of hydrovanes to the landing gear to make water landings safer. The Sopwiths were based at Moutchic and used for training. Two were subsequently sent to the base at Pauillac. One of these was sent to the United States, where it was given serial A 5660. After the war an additional 21 French-built Sopwiths were obtained from the U.S. Army. They were given serials A 5725-A 5728 and A 5734-A 5750 and used for observation. One was carried by the battleship USS Texas during 1919 maneuvers in the Caribbean.


Sopwith 1 1/2 Strutter 1B1 Single-Seat Bomber with 135-hp Clerget 9Ba or Bb
   Span 10.2 m; length 7.7 m; height 3.125 m; wing area 32.25 sq. m
   Empty weight 592 kg; loaded weight 975 kg
   Maximum speed:
1,000 m 160 km/h
2,000 m 156 km/h
3,000 m 147 km/h
4,000 m 136 km/h
   Climb:
1,000 m 5 minutes 40 seconds
2,000 m 15 minutes 20 seconds
3,000 m 18 minutes 50 seconds
4,000 m 31 minutes
   Ceiling 4,725 m; endurance 3 hours 45 minutes
   Armament: one fixed, synchronized 7.7-mm Vickers machine gun and 150 kg of bombs
   Between 4,200 and 4,500 Sopwith 1 1/2 Strutters of all types were built in France

Sopwith 1 1/2 Strutter 1A2 Two-Seat Reconnaissance Aircraft with 135-hp Clerget 9Ba or Bb
   Span 10.2 m; length 7.7 m; height 3.125 m; wing area 32.25 sq. m
   Empty weight 597 kg; loaded weight 1,062 kg
   Maximum speed: 158 km/h at 3,050 m; climb to 1,980 m in 12 minutes 40 seconds; ceiling 3,960 m
   Armament: a fixed, synchronized 7.7-mm Vickers machine gun and a 7.7-mm machine gun on a swivel mount

Sopwith 1 1/2 Strutter 1B1 Single-Seat Bomber with 135-hp Le Rhone 9Jby
   Span 10.2 m; length 7.7 m; height 3.125 m; wing area 32.25 sq. m
   Empty weight 626 kg; loaded weight 926 kg
   Maximum speed: 156 km/h at 3,000 m; climb to 2,000 m in 11 minutes; climb to 3,000 m in 18 minutes; ceiling 3,960 m
   Armament: a fixed, synchronized 7.7-mm Vickers machine gun and 150 kg of bombs

Sopwith 1 1/2 Strutter with Smaller Empennage and 135-hp Clerget 9Ba or Bb
   Span 10.2 m; length 7.7 m; height 3.125 m; wing area 32.25 sq. m
   Maximum speed:
2,000 m 165 km/h
3,000 m 157 km/h
4,000 m 146 km/h
   Climb:
1,000 m 5 minutes
2,000 m 12 minutes 20 seconds
3,000 m 22 minutes 50 seconds
4,000 m 38 minutes 10 seconds
   Ceiling: 4,880 m

Sopwith 1 1/2 Strutter 1A2 Two-Seat Reconnaissance Aircraft with 145-hp Clerget 9Bc
   Span 10.2 m; length 7.7 m; height 3.125 m; wing area 32.25 sq. m
   Empty weight 626 kg; loaded weight 926 kg
   Maximum speed: 161 km/h at 3,000 m; 150 km/h at 4,000 m; climb to 3000 m in 24 minutes; climb to 4,000 m in 41 minutes; ceiling 3,960 m
   Armament: one fixed, synchronized 7.7-mm Vickers machine gun and a 7.7-mm machine gun on a swivel mount

A.Durkota, T.Darcey, V.Kulikov The Imperial Russian Air Service (Flying Machines)

Lebedev Factory

Sopwith 1-1/2 Strutter

  An order was placed for 260 Sopwith 1-1/2 Strutter aircraft with 130hp Clerget engines, to be manufactured at either the Taganrog or Yaroslav facilities. Only five were built in 1917.

O.Thetford Aircraft of the Royal Air Force since 1918 (Putnam)

Sopwith 1 1/2-Strutter

   Although obsolescent by April 1918, a few 1 1/2-Strutters remained in the RAF on Home Defence duties with No 78 Squadron at Sutton’s Farm until July 1918, being replaced by Sopwith Camels, and with No 78 Squadron at Goldhanger and Stow Maries. On Home Defence duties, it was usually flown as a single-seater with two synchronised machine guns firing forward. One 110hp Clerget rotary. Span, 33ft 6in; length, 25ft 3in. Loaded weight, 2,363lb. Max speed, 100mph at 6,500ft; service ceiling, 15,000ft.

G.Swanborough, P.Bowers United States Military Aircraft Since 1909 (Putnam)

SOPWITH 1A2

   The Sopwith “1-1/2- Strutter”, so named by the British because of its extra centre section struts, was a notable military aircraft before American entry into World War I. The French obtained large quantities of the two-seat observation version, which they named Sopwith 1A2, and the single-seat bomber version 1B1, by purchase and license manufacture. When the A.E.F. desperately needed aeroplanes in 1917/18, the French sold 514 Sopwiths (384 As and 130 Bs) to the Americans.
   Span, 33 ft. 6 in.; length, 25 ft. 4 in.; area, 353 sq, ft.; weight, 2,061 lb.; speed, 95 m.p.h.

G.Swanborough, P.Bowers United States Navy Aircraft Since 1911 (Putnam)

SOPWITH 1 1/2-STRUTTER

Among the Navy's British purchases during World War I were two-seat Sopwith 1 1/2-Strutters, widely used as observation and training types by both France and Britain. The one example shipped to the States received serial A5660. An additional 21 obtained from the US Army after the war became A5725-A5728 and A5734-A5750. These were used as light observation types. Power plant was a 130 hp Clerget. Span, 33 ft 6 in; length, 25ft 3in; gross weight, 2,150 lb; max speed, 100 mph.

L.Andersson Soviet Aircraft and Aviation 1917-1941 (Putnam)

Sopwith 1 1/2-Strutter

   The single-bay biplane known as the 'Sopvich' in the Soviet Union had long sloping struts between the fuselage and the upper wing and was originally named Sopwith 1 1/2-Strutter because of these extra centre section struts. Developed in 1915 primarily for the Royal Naval Air Service, it was delivered to that Service from February 1916, but was soon accepted by the Royal Flying Corps as well. The Sopwith was an immediate success in the reconnaissance, patrol and day bombing roles. The pilot's fixed Vickers machine-gun was mounted on the centre line of the forward fuselage and it was one of the first British aircraft fitted with a machine-gun firing through the propeller arc by means of interrupter gear. Furthermore the famous Scarff gun ring-mounting was first developed for the 1 1/2-Strutter.
   Apart from the strut arrangement and the armament the 1 1/2-Strutter was of conventional design for its period. A circular cowling enclosed the rotary engine which drove a two-blade wooden propeller. The pilot's cockpit was located well forward of the leading edge of the lower wing, while the rear cockpit was behind the trailing edge of the upper wing. The rudder and elevators were unbalanced and the fin had a peculiar rounded forward end. The staggered wings were straight and of parallel chord and unbalanced ailerons were fitted. British- and French-built versions had different wire bracing arrangement. The undercarriage was of normal V type.
   In addition to the reconnaissance version there were single-seat and two-seat bomber versions and many aircraft were built as trainers without the gun ring in the rear cockpit. Over 1,500 were produced in Great Britain and more than 4,000 in France, as the Sopwith 1A2, Sopwith 1B2 and Sopwith 1B1 (single-seat). The 1 1/2-Strutter was also used by Belgium, Russia and the USA. After the war it served with the air forces of Japan and Romania and, in small numbers, also in a few other countries.
   Some 125 Sopwith 1 1/2-Strutters were delivered to Russia from Great Britain and a number was built under licence. At least thirty-four were taken over by the RKKVF in 1917 and several were captured in 1919-1920, both British- and French-built examples. The Soviet Latvian Air Force had seven in 1918-19. Some were captured from the RKKVF in 1919 - at least one by Latvian troops, one by Estonia and one by Lithuania (A 1527, which became the first aircraft of that country's air force). Most Sopwiths used by the RKKVF had 130hp Clerget engines, but some were fitted with the 120hp Le Rhone. The Sopwith was one of the most numerous aircraft types in the RKKVF before 1922 and many were also built by Duks in Moscow, later GAZ No. 1 Aviakhim. One was modified by V P Grigorev at the Kiev Polytechnic Institute and fitted with a 185hp Opel engine and an undercarriage taken from a Rumpler.
   At the end of 1920 a total of 130 Sopwiths were in service, of which eighty-two remained one year later. In 1921 they served in all military districts but the largest numbers were assigned to the Eastern Front district, North Caucasia, Caucasia, the Ukraine, Kiev, Khar'kov, Turkestan and the 5th Army in Siberia. A few aircraft were added to the inventory, the last batch built by GAZ No. 1 in 1922 consisted of about twenty-five machines (c/ns 2322-2346 probably). The Sopwith served with the following RKKVF units:
   Until 1922: the 3rd, 9th, 11th, 15th and 18th Aviaotryady
   Until 1923: the'15th Otdel'nyi razvedivatel'nyi aviaotryad at Smolensk (120 and 130hp Sopwith lA2s) and the 1st Razvedivatel'naya eskadril'ya of the Aviatsionnaya eskadra No. 2 at Kiev (2nd otryad only initially)
   Until 1924: the 7th Otdel'nyi razvedivatel'nyi aviaotryad at Klin (from 1923), the 10th Otdel'nyi razvedivatel'nyi aviaotryad at Rostov (from 1922, also had Halberstadts and Rumplers), the 16th Otdel'nyi razvedivatel'nyi aviaotryad at Irkutsk (from 1922) and the 17th Otdel'nyi razvedivatel'nyi aviaotryad at Chita (1924 only)
   Until 1925: the 18th Otdel'nyi razvedivatel'nyi aviaotryad at Chita (from 1922).

   Single examples were used by many other units and by the NOA. Relegated to second-line roles the Sopwith was assigned to the aviabazy and in small numbers to the 1st Military School of Pilots at Kacha, the Higher Military School of Aerial Observers in Leningrad, the Strel'bom school at Serpukhov, the 1st Higher School of Military Pilots, the School of Military Photography and the Training eskadril'ya in Moscow. Sixty-nine remained by October 1924. Many were written off in 1925 but about ten were retained, some until 1929. In December 1928 there were two with the 50th Aviaotryad (c/ns 189 and 8746) and two at the 2nd Voennaya shkola letchikov (c/ns 2322 and 2328).
   Some were exported to Afghanistan (one in 1921 and a few more in 1925) and others were handed over to the ODVF late in 1924 and in 1925. These included the following aircraft:
   Tomich, flown by Bazhenko and Maslennikov at Tomsk and Novonikolaevsk, Siberia. C/n 1786, flown at Novgorod.
   Krasnaya zvezda, flown by Fadeev for the first time after assembly on 8 October 1925 at Yakutsk. Officially presented to the ODVF in November 1925.
   Krasnoyarets, flown by Baturin at Krasnoyarsk in 1925.
   Stalinets, flown at Stalingrad. Written off in 1926 and given to a museum.
   One flown at Orenburg, Bashkiriya, in 1925.

Known identities of Soviet Sopwith 1 1/2-Strutters:
   (British- and French-built aircraft) 352/3, 4/H, 5 to 7, 9, 10, 18, 34, 35, 37,39,123,125,126,171,175,189, 200, 214, 219, 238, 241, -/252, 257, 4/258, 260, 296, 298, 299, 301, 302, 306, 326, 339, 402, 418, -/514, 1202/536, 1786, 2000, 2316, 2341-2343, 2357, 2360, 2366, 2368, 2379, 2403, 2407, 2410, 2523, 2557, 2595, 2723, 3131, 3159, 3191, 3407, 4056, 4065, 5760, 4C6078, 6804 and 7046.
   (Mostly British-built aircraft) 985, 1000, 1002, 1003, 1006, 1010, 1013, 1015, 1017-1022, 1527, 1552/538, 2383, 2395, 2396, 2398, 2411, 5219, 5247, 5248, 5975, 6925, 6930, 6934, 6950, 8179, 8204, 8266, 8312, 8316, 8323, 8324, 8744, 8746 and 8749 (prob- ablv/possibly including ex-A985, A1527, A1552, N5219, A5247, A5243, A5975, A6925, A6930, A6934, A6950, A8179, A8204, A8266, A8312, A8316, A8323, A8324, A8744, A8746 and A8749)
   Aircraft in the 2322-2338 range were probably GAZ No. 1-built.

130hp Clerget
   Span 10.2m; length 7.7m; height 3.12m; wing area 32.8m2
   Empty weight 593kg; loaded weight 975kg
   Maximum speed 149km/h; climb to 1,000m in 4.4min; ceiling 4,700m; endurance 3'zhr

Журнал Flight

Flight, February 6, 1919.

"MILESTONES"

THE SOPWITH MACHINES

The 1 1/2-Strutters. (December 12, 1915, and June 7, 1916)

   The Sopwith 1 1/2-Strutter has claims to great historical distinction, not only for its great capabilities for use as a fighter, but because, indirectly, it set a new fashion in aerial fighting, being the first British aeroplane to carry a synchronized gun firing through the propeller. The Sopwith-Kauper synchronisation gear which made this possible was developed at the Sopwith works, and was as much a product of this firm as was the machine in which it was installed. It was also fitted with the Scarff gun ring for the gunner, which has since become such a well-established feature on all fighters. The 1 1/2-Stnrtter was originally designed as a high-performance two-seater fighter, with a 100 h.p. Clerget engine. At the time of its introduction it was justly regarded as an extraordinarily good 'bus, having an excellent performance and a good manoeuvrability. Incidentally it established a world's altitude record for an altitude of 23,980 ft. In view of its good performance, coupled with its (for the times) excellent armament, the 1 1/2-Strutter had a tremendous success, and it is not surprising that many machines were built to the order of the Governments of Roumania, Russia, America and Belgium. In addition, it might be mentioned that the French Government has manufactured under licence no less less than 4,500 machines of this model. In addition to the novel points connected with the mounting and firing of the guns carried, the 1 1/2-Strutter was interesting in several other respects. Thus the wing bracing - which gave it its name - was very unusual, and in a modified form set a new fashion, so to speak. The top plane was in two halves, bolted to the top of a central cabane, while the spars were provided with an extra support in the shape of shorter struts running from the top longerons to the top plane spars some distance out. In the single-seaters to follow this bracing of the top plane was generally adopted, with the exception that the central cabane was done away with, the outer struts of the W formation having a slightly less pronounced slope, and supporting a separate top plane centre section. Aerodynamically the 1 1/2-Strutter is of interest in being fitted with, an air brake in the form of adjustable flaps in the trailing edge at the lower plane adjacent to the fuselage. These flaps could be rotated by the pilot until they were normal to the wind, thus helping to pull the machine up when about to land.
   A more successful innovation incorporated in this machine was the trimming gear, by means of which the angle of incidence of the tail plane could be altered during flight. In this manner the difference in weight of the passenger carried could be counteracted by the tail setting, and also the tail could be adjusted for high speed, climbing, &c. This feature has since become universal practice on passenger-carrying machines.

The 1 1/2-Strutter Bomber

   Originally designed as a two-seater fighter, the 1 1/2-Strutter was later adopted as a single-seater bomber, and it is the machine which has been so successful in bombing, with good results, such towns as Essen, Munich and Frankfort. For bombing work the 1 1/2-Strutter was equipped with a 130 h.p. Clerget, which afterwards took the place of the 110 h.p. Clerget in the standard two-seater fighter model. It might also be mentioned that fairly recently the French Government converted a large number of two-seaters into school machines with dual controls. These machines are fitted with 80 h.p. Le Rhone engines.