А.Александров, Г.Петров Крылатые пленники России
ХАННОВЕР (ХАВА) CL-II/CL-III/CL-IIIa / HANNOVER (HAVA) CL-II/CL-III/CL-IIIa
Цельнодеревянный двухместный биплан со смешанной обшивкой. Несущие и рулевые поверхности покрыты полотном, фюзеляж - фанерный полумонокок с алюминиевым капотом.
Самолет разработан весной 1917 года конструкторским коллективом авиастроительного филиала ганноверской фирмы "Ханновериш Вагонфабрик" (в немецком сокращении - "Хава") под руководством Германа Дорнера.
Создатели новой машины поставили перед собой непростую задачу добиться максимально возможного при бипланной схеме увеличения зоны обстрела турельного пулемета и одновременно - сохранения широкого поля обзора для летчика.
Этим объясняется оригинальное бипланное оперение из двух маленьких стабилизаторов вместо одного большого и "опущенное" почти до фюзеляжа верхнее крыло. В целом компромисс получился вполне удачным. Летнаб имел практически круговой обстрел и мог вести огонь не только в задней, но и в передней полусфере. А обзор на взлетно-посадочных режимах оценивался гораздо выше, чем у аналогичного "Роланда" С-II.
В июле 1917-го "Хава" успешно прошел испытания и был принят на вооружение в качестве разведчика, легкого штурмовика и двухместного истребителя сопровождения. В ноябре первые серийные машины поступили на западный фронт.
С начала 1918 года их стали применять для непосредственной поддержки войск на поле боя.
Самолет неплохо проявил себя в воздушных боях и в действиях против наземных целей. Он обладал отличной маневренностью, легкостью управления и высокой выносливостью, хорошо "держал" боевые повреждения.
Опытный пилот "Ханновера" мог выиграть схватку на виражах у большинства одноместных истребителей Антанты. Соответственно, и относительные потери среди экипажей этих машин были ниже, чем в эскадрильях "Альбатросов", "Румплеров" или "Эльфауге".
Аппарат выпускался крупными партиями на заводах "Хава" и "Роланд". До конца войны построено 433 CL-II, 80 CL-III и 573 CL-IIIa. Еще 38 машин сдано уже после заключения перемирия.
"Apryc"As.III, 180 л.с. (CL-II и CL-IIIa) или "Мерседес"D.III, 160 л.с. (CL-III).
1 синхронный "Шпандау", 1 турельный "Парабеллум".
(с двигателем "Аргус")
Размах, м 11,7
Длина, м 7,6
Площадь крыла, кв.м 32,7
Сухой вес, кг 717
Взлетный вес, кг 1081
Скорость максимальная, км/ч 165
Время набора высоты, м/мин 1000/5,3
Потолок, м 5000
O.Thetford, P.Gray German Aircraft of the First World War (Putnam)
Hannover CL II, III and IIIa
Hannoversche Waggonfabrik A.G. had long been famous as railway-rolling-stock constructors when in 1915 they were required by the German Government to undertake the construction of aeroplanes. When the aircraft branch was eventually established at Hannover-Linden the first types to be built under licence were the Aviatik C I, Rumpler C Ia and Halberstadt D II. As the production of aircraft got into its stride during 1916, so the drawing office, under the guidance of Hermann Dorner (who was one of the pioneers of German aviation), gave thought to a machine of their own. During 1917 the Flugmeisterei had issued a specification calling for a lighter type of C class two-seater, to be powered by a 160-180 h.p. engine and classified in the new CL category. Instead of the reconnaissance, photographic and artillery-observation duties performed by the standard C types, the CL machines were to act more as two-seat fighters, to be deployed as offensively as possible and to act as escort (Schutzstaffeln) to the C class machines. Later the Schutzstaffeln were redesignated Schlachtstaffeln (Battle Flights) and additionally used to co-operate with the ground troops in low-level straffing and harassing of the opposing infantry lines and rear areas.
To fulfil this specification Dorner produced the Hannover CL II (there was no CL I; having already built Av C I, the next numeral was simply allotted to the CL category) powered with an Argus As III engine of 180 h.p., and developed it, with little modification, into CL III and IIIa. The main difference in the types was in the type of engine and in the wingtips. The prototype CL II had uniform dihedral of 2° in both wings, and the upper tailplane was of angular outline. In the production aircraft the dihedral was differential, and the upper tailplane of familiar (approximately semicircular) shape was standardised. The wingtips had a plainly raked tip and the ailerons were not overhung as in later models.
Modification of the wingtips, together with ailerons incorporating overhung balances, was introduced in the CL III, which also differed in mounting a 160 h.p. Mercedes D III motor. However, as these Mercedes motors were required more urgently for the single-seat fighters, the CL III reverted to the 180 h.p. Argus As III. In this guise the machine was known as the CL IIIa, and this variant saw the greatest quantity production.
The Hannover, as a single-engined aircraft, was unique in having a biplane tail. Such a feature had previously been seen only on multi-engined aircraft. Its purpose was to reduce the tailplane/elevator span, thereby affording a wider field of fire for the observer, an object which was achieved in no small measure. For a two-seater the CL IIIa was a smallish (under 40 ft. span) and compact single-bay aircraft, and was often attacked by Allied scouts in mistake for a single-seater, whereupon they were speedily disabused of their illusion by the hail of fire from the observer's Parabellum machine-gun. Due to the positioning of the upper wing so close to the fuselage, the pilot had an excellent upward field of vision, and the much narrower chord of the lower wing, together with the nature of the stagger, afforded good downward and forward visibility. The compactness of the aeroplane gave excellent manoeuvrability, and it had particularly good lateral control due to the large balanced ailerons.
The fuselage was built on a basic structure of four main longerons with ply formers; forward the section was rectangular, except for the rounded decking; aft of the cockpits the section was developed into a more oval shape. Covering of the fuselage was thin ply sheet covered with doped fabric. Removable panels adjacent to the engine were metal, as was the extreme nose cowling. The deep, roomy fuselage tapered to a vertical knife-edge aft, where the vertical fin was built integral with the structure and was likewise ply and fabric skinned; the lower, deeply cambered tailplane was also similarly covered. The flat-plate section upper tailplane and both sets of elevators were of steel-tube framing and fabric covered; the elevators were connected by a link strut inside the fin and operated by a crank attached to the lower set. Some of the earlier aeroplanes had the two tailplanes connected with a vertical bracing strut, but later the structure was internally strengthened and these struts deleted.
The wings were of conventional wooden construction, based on two box-spars, and had a small degree of sweep, some 1.5°. The lower wings had a pleasantly rounded tip profile, which doubtless contributed to the excellent lateral control. The ailerons were, like the elevators and rudder, of steel-tube framework and fabric covered. All bracing wires were of stranded cables.
Both undercarriage vee struts and interplane struts were of plain circular steel tube with wooden fairings taped on to strengthen and produce a streamlined section. The wheels were sprung with triple coil springs, and the ash tailskid was fastened to the small underfin and sprung with elastic cord.
Hannoveranas - as they were dubbed by the R.F.C. - came into operational use towards the end of 1917, and were, without doubt, formidable opponents. As was the case with most aircraft with ply-covered fuselages, they were immensely strong and could take considerable punishment. In his biography Flying Fury Major J. B. McCudden, V.C., D.S.O., M.C., M.M., wrote:
"I went down to engage him and found that he was a Hannover, a machine which has a biplane tail, and although I fired a lot at him at close range, it had no other effect than to make him dive away, which made me think that perhaps they were armoured. These machines are very deceptive, and pilots are apt to mistake them for Albatros scouts until they get to close range, when up pops the Hun gunner from inside his office."
This was on 1st January 1918; on 26th February 1918 he again reported:
"Then I flew up north, and very soon encountered two Hannovers, whom I fought for some time, but I finally had to leave them, for they were co-operating very well and had started to shoot me about."
Johann Baur, who later in life became personal pilot to Hitler, flew Hannovers for a time and claimed for himself nine victories.
Over a thousand Hannover two-seaters were built for the German Air Force. Of this total, 439 were CL IIs , 80 CL IIIs and 537 IIIas.
Description: Light two-seat C type, escort and close support.
Manufacturers: Hannoversche Waggonfabrik A.G. (Han.).
Sub-contractor: Luftfahrzeug Gesellschaft m.b.H. (Rol.). (These aircraft were designated CL IIa.)
Power Plant: One 180 h.p. Argus As III 6 cylinder in-line water-cooled engine (CL III with 160 h.p. Mercedes D III.)
Dimensions: Span, 117m. (38 ft. 4 3/4 in.). Length, 7.58 m. (24 ft. 10 1/2 in.). Height 2.8 m. (9 ft. 2 1/4 in.). Area, 32.7 sq.m. (353 sq.ft.).
Weights: Empty, 717kg. (1,577 lb.); captured aircraft, 1,732 lb. Loaded, 1,081 kg. (2,378 lb.); captured aircraft, 2,572 lb.
Performance: Maximum speed, 165 km.hr. (103.12 m.p.h.) at 5,000 m. (16,400 ft.). Climb, 1,000 m. (3,280 ft.) in 5.3 min. Ceiling, 24,600 ft. Duration, 3 hr.
Armament: One fixed Spandau machine-gun forward and one manually operated Parabellum machine-gun in rear cockpit.
N.B. An example powered with 190 h.p. N.A.G. motor was designated CL IIIb, and an experimental two-bay version was designated CL IIIe.
Hannover CL IIIb
Variant of standard CL IIIa airframe with extended wings of two-bay format. No data as to actual span available. So far as is known, only the single prototype was constructed.
W.Green, G.Swanborough The Complete Book of Fighters
HANNOVER CL II Germany
The concept of the comparatively light and manoeuvrable two-seat "defensive patrol and pursuit” aircraft realised by the German Air Staff in the autumn of 1916 led to the issue of three-prototype contracts to several manufacturers, including the Hannoversche Waggonfabrik AG. Initially designated C II, but redesignated CL II in the summer of 1917, the company’s contender, designed by Dipl-Ing Hermann Dorner, successfully completed its Typenprufung on 21 July 1917. Powered by a 180 hp Argus As III water-cooled engine, the Hannover CL II was armed with a single fixed LMG 08/15 machine gun and an LMG 14 machine gun on a flexible mounting. Within two months of the type test, the Idflieg placed orders for 500 CL IIs and these were introduced into service from October 1917. The CL II proved exceptionally versatile, and, in addition to its fighter roles, it was utilised for low-altitude tactical reconnaissance. Its manoeuvrability was such that its crews were able to engage enemy single-seat fighters with confidence. The maximum frontline complement of 295 aircraft was attained in February 1918, after which the CL II was progressively phased out in favour of the CL III and IIIa. The Hannoversche Waggonfabrik built 439 CL IIs, the remainder of the contract being completed as CL IIIa’s, and Roland licence-built 200 CL II(Rol) aircraft in 1918 for use as advanced trainers.
Max speed, 102 mph (165 km/h).
Climb to 3,280 ft (1000 m), 6.1 min.
Empty weight, 1,653 lb (750 kg).
Loaded weight, 2,447 lb (1110 kg).
Span, 39 ft 2 1/2 in (11,95 m).
Length, 25 ft 7 in (7,80 m).
Height, 9 ft 0 1/4 in (2,75 m).
Wing area, 363.8 sq ft (33,8 m2).
HANNOVER CL III Germany
A progressive development of the CL II designed by Hermann Dorner, the CL III was intended to offer improved altitude capability with the 160 hp Mercedes D III water-cooled engine. Despite some airframe strengthening, the CL III had a slightly reduced structural weight and marginally smaller overall dimensions. The Typenprufung was successfully passed on 23 February 1918, and an order placed for 200 aircraft with deliveries to commence in the following month. In the event, as a result of shortages of the Mercedes engine, only 80 CL IIIs were delivered, the remainder of the order being completed with the 180 hp Argus As III(O) licence-built by Opel as the CL IIIa. This version was to remain in production until the end of hostilities, 573 being delivered. The designation CL IIIb was allocated to the version that was to have been powered by the 185 hp NAG C III engine, and the CL IIIc was a twin-bay version built specifically as a test-bed for the NAG engine. The CL III and IIIa entered service in April 1918, serving primarily with the Schlachtstaffeln operating in the ground attack fighter role. Oddly, the Hannoversche Waggonfabrik completed a further 100 CL IIIs and 38 CL IIIa's after the Armistice. The following data relate to the CL IIIa.
Max speed, 103 mph (165 km/h) at 16,405 ft (5000 m).
Time to 3,280 ft (1 000 m), 5.3 min.
Endurance, 3 hrs.
Empty weight, 1,653 lb (750 kg).
Loaded weight, 2,447 lb (1110 kg).
Span, 38 ft 4 1/2 in (11,70 m).
Length, 24 ft 10 1/4 in (7,58 m).
Height, 9 ft 2 1/4 in (2,80 m).
Wing area, 351.97 sqft (32,70 m2).
Flight, April 25, 1918.
A GERMAN "MYSTERY" BIPLANE - THE H.W.
[From time to time reports have been received of a certain type of German aeroplane having a biplane tail being observed at the front. Reports differed considerably as to the exact shape of the machine generally, but all appeared to tally regarding the biplane tail. Our excellent French contemporary "l Aerophile" has previously called attention to this unusual tail plane arrangement, which had been observed both from the ground and by French aviators - at a distance. Now, however, one of these machines has been brought down on the French front, but unfortunately the smash and the subsequent fire did not leave much on which to base a reconstruction of the machine. The only clue to its identity appears to be that it was marked H.W., which initials are variously interpreted as "Halberstadt Werke" and "Hannover Werke." Be that as it may, the following notes from our French contemporary, and the two sets of diagrams representing the probable approximate appearance of the machine, should be of interest, and we would ask any of our readers who may have seen this machine to send us a rough sketch of what is, in his opinion, the general form of it. In this manner it may be possible to piece together sufficient to arrive at a fairly accurate idea of the characteristics of this German "mystery" machine. - ED.]
A RECONSTRUCTION of the H.W. biplane has been attempted, based on the wreckage of one of these machines brought down on the French front, where it was badly burnt. This reconstruction takes the form shown in the accompanying sketch. The H.W. biplane is a two-seater. The span of the upper wings is approximately 11 metres, and of the bottom wings about 10 metres. The wings have a dihedral angle but no sweep-back, and are staggered. The upper wings are of trapezoidal plan form with balanced ailerons, the trailing edge of which is extended, giving somewhat the appearance of the old Taubes. The lower wings are also of trapezoidal plan form, but have the rear corners rounded off.
On each side of the fuselage there is one pair of inter-plane struts, sloping forward in conformity with the stagger and also sloping outward as shown in the front view. These struts are in the form of stream-line steel tubes.
The tail is of the biplane form, the top plane of it being considerably smaller than the bottom one. We have already indicated the armament: two machine guns, one in front and one behind. We may add that certain machines of this type have been fitted with bomb racks, while another was equipped with a camera. This is natural as the machine belongs to the C class (general utility). The accompanying sketches illustrate the differences between the different versions.
The plan form of the wings is almost definitely determined, but the ailerons, which have rounded tips in the diagrammatic reconstruction, come to a point in the sketch drawn by Lieut. Mussat. In the first case the tail plane is rounded and the fin and rudder of polygonal contour. The contrary is indicated in the letter from our correspondent, who says : "I insist in particular on the following points: The fuselage is very deep, and the top plane is very close to it. The contour of the rudder and its fin is very rounded and not polygonal as in the reconstructed view. The tail planes are polygonal in plan view, with the angles rounded off."
In reconstructing the machine the length of each top wing was found to be 4 metres 70 from root to tip. The span found for the bottom wing was in the neighbourhood of 11 metres, and as, according to all the observers who have had an opportunity of seeing the machine, the bottom plane was of smaller span than the top one, it was concluded. that there must have been a fixed centre section in the top plane. No trace has, however, been found of such a centre section.
Our correspondent calls our attention to the deep fuselage close to which is the top plane. On the other hand our contributor, Jean Lagorgette, who, from the hospital, follows closely any novelties, advances the following hypothesis: If there was a fixed centre section it would probably be made of steel tubes. [The inference being that it would in that case have survived the flames. - ED.] If no trace has been found of it or of its cabane, this centre section does not exist, and the top wings attach directly to the body as in the Roland.
In any case, the fuselage being high, the rear gunner would be able to fire upwards. According to observers on the ground this machine is very fast and has a high "ceiling."
Flight, May 23, 1918.
THE "GERMAN" MYSTERY BIPLANE.
IN our issue of April 25th, we published sketches of a German biplane, the identity of which was somewhat in doubt. We also requested readers who might have had an opportunity of seeing this machine to send us any information concerning it for the benefit of others. In response to this request we have now received the accompanying set of sketches and descriptive matter. Our correspondent is good enough to say "that 'FLIGHT' always gives us such useful information about German planes that it is only fair to pass on what we know."
"The machine," our correspondent says, "is believed to be an H.W.F. (Hannoversche Waggon Fabrik). The fuselage is deep in side view. The struts slightly converge on lower wing. When seen overhead both leading and trailing edges of top wing are clear beyond respective edges of lower wing. Struts on tail plane slope inwards on lower tail plane. Narrow fuselage when viewed from underneath. In front view there is one pair of struts either side of fuselage, sloping inwards on lower wing. This machine is a two-seater, and is generally camouflaged with its crosses painted inside white circles."
Flight, May 30, 1918.
THE GERMAN H.W. (HANNOVERSCHE WAGGONFABRIK) BIPLANE.
[In our issue of May 23rd, we published some sketches and brief particulars of the German "Mystery" biplane, sent to us by a correspondent in France. Since then we have had an opportunity to examine in detail one of these machines, captured intact. The machine bears in numerous places transfers with the name "Hannoversche Waggonfabrik," and there is thus no longer any mystery attaching to its identity. On the whole the sketches and description sent us by a correspondent were fairly accurate, as will be seen from the accompanying illustrations. We can only deal briefly with the Hannover biplane this week, but hope to return to it in detail as soon as opportunity offers. As the wings were not in place on the machine we examined it has not been possible at present to obtain a view of the complete machine, but the sketches of the body and tail should nevertheless give a good idea of the most characteristic features. - ED.]
THE most interesting feature of the Hannover biplane, apart from the biplane tail which first drew attention to the machine, is the unusually deep body. Without having actually measured the depth of the body we should judge its maximum depth to be in the neighbourhood of 5 ft. The reason for choosing such a deep body, the cross sectional area of which is great and must, it would appear, necessarily have a fairly high resistance, is somewhat difficult to follow unless it be assumed that the object has been to bring the heads of the occupants almost in line with a continuation of the chord line of the upper plane, thus giving pilot as well as gunner a practically unobstructed view in a forward and upward direction. Whether or not this has been the cause cannot be definitely stated, but it would certainly appear to have had that effect. As if to further ensure that the gunner was free to look forward in line with the top plane, his gun ring is mounted in a form of turret, elevated some distance above the main top of the body. It is possible that the gunner has been able to increase his arc of fire beyond that usually coming within the providence of the crew of the rear gun, and fire forward between the planes. This would be possible on account of the fact that there is only one pair of inter-plane struts on each side of the body, the lift cables therefore running out at a rather flatter angle than is usual in a machine of this size. There would, of course, always be the danger of hitting a lift wire, unless a stop were provided preventing the gun from being fired when in line with a wire. Of this there does not appear to be any sign, and it is possible that the designer trusts to the gunner to refrain from firing while the muzzle of the gun is too close to a wire. That this little detail might easily be overlooked in the excitement of a scrap seems probable, but perhaps the German attitude towards this particular subject is the same as that expressed to us some time ago by a French friend while discussing this same feature. Our friend expressed himself as follows: "Well, suppose you do hit one of your own wires. You come down. C'est la guerre." However, most pilots would probably prefer to leave the pinging of his wires to the other chap.
Constructionally the body of the Hannover biplane is that now so frequently found on German machines, a light framework covered with three-ply. In section, however, the body is somewhat unusual, in that at the point of maximum depth it has flat sides and bottom, with a curved deck, while near the nose the section is nearly circular and the tail portion is oval in section, not unlike the tail of a fish. This seems rather the reverse of usual practice.
In the gunner's cockpit there is the usual hinged seat which can be swung back out of the way when the gunner wishes to fire from a standing position. On the port wall of the body there is a wood drum around which the aerial is wound, passing through a wide tube fitting in holes in the bottom of the body. Centrally placed, in front of the gunner's feet, is a framework of steel, mounted so as to pivot around a transverse horizontal axis, and telescopically sprung by two short lengths of tubes and coil springs, which appears to have been used for releasing the bombs. Immediately under this framework there is a sliding trap door in the floor, which reveals, when removed, another compartment underneath the floor boards, between them and the bottom of the body. It is, in fact, a sort of cellar, and a humorously-minded visitor suggested that this was where the gunner kept his lager, but closer inspection revealed the fact that in this compartment, and immediately underneath the other, was another sliding trap door, operated by a rather clumsy arrangement of cables and pulleys, surrounded by a rail some eight inches high. When both doors are open the way is clear for the bomb to drop. The bombs were apparently carried in racks on the floor to the right of the release gear, while on the left a number of fittings appear to indicate that here was at one time mounted the wireless set. On the starboard wall of the body is a lever marked Kupplung (Clutch), which has probably been used for throwing the wireless into and out of gear. On the starboard wall are also a couple of electric connections of the wall plug type, used, evidently, for connecting up the gunner's electrically heated suit with the generator circuit. No gun was mounted on the machine we examined, but the gun ring and pivot were of the usual type.
In the pilot's cockpit there were the usual instruments on a dash, and in addition a couple of inclinometers of somewhat unusual type, one for indicating lateral inclination, mounted on the dash, and another for longitudinal angularity mounted on the starboard side of the cockpit. These inclinometers appeared to consist of an upper semicircle painted blue, which was fixed, and a lower semicircle, red in colour, which always remained horizontal, In appearance, the lower semicircle was like a piece of ruby glass, but probably a closer inspection would prove it to be a liquid contained in a semicircular container.
The controls did not present anything of especial interest. The control column terminated at the top in a double handle, the two parts of which sloped slightly downwards. On this was mounted the trigger for the machine gun, of which only one appears to have been fitted for use by the pilot. The seat was mounted on top of the main petrol tank, a large cylinder placed transversely on the floor of the cockpit. At the pilot's right hand was a hand operated pressure pump, which had a rearward extension enabling it to be worked by the gunner at will. A stamp on the wall of the cockpit gave an indication of the date of manufacture. The stamp read ZAK - which apparently corresponds to our A.I.D.-6/12/17.
Although not in place on the machine we inspected, the wings were available for examination and showed that the span of upper and lower wings was approximately equal. The chord of the upper plane was considerably greater than that of the lower. There was only one pair of interplane struts on each side in spite of the considerable span of the machine, and the top plane had a centre section mounted on two pairs of N's sloping out slightly. The tips of the top plane were raked, and the wing flaps balanced and warped. The lower planes, on the other hand, had rounded tips of the shape commonly known as Bleriot tips from their similarity to the wing tips of that well-known designer's early monoplanes. In the middle of the centre section of the top plane the trailing edge had been cut away, and between the spars were mounted, on the port side the petrol service tank, and on the starboard side the radiator. The latter was partly covered by a semicircular shutter which could be rotated out of the way to give increased cooling. The amount of variation in cooling thus obtainable appeared, however, to be very small.
The motive power was furnished by an Argus engine; partly covered in, each three cylinders of which had a common exhaust collector projecting out past the struts of the starboard "N" carrying the top plane centre section. The under carriage was of the Vee type, and appeared to follow along standard lines.
As regards the biplane tail planes, the arrangement of these will be easily followed from an inspection of the illustrations. In design they did not appear to present anything very unusual, and the only point of interest appears to be that although the two fixed planes are connected by struts there is no wire bracing. Each plane is therefore to be considered a simple cantilever, and as their section did not appear to be very deep, the strength would not appear to be all that it might. One can only wonder at the reason for employing a biplane tail. Probably it is to be sought for in the effect of the down draught from the wings, placed as they are close to the top of the body.
Flight, September 5, 1918.
THE: HANNOVEHANER BIPLANE.
Report issued by Technical Department (Aircraft Production), Ministry of Munitions.
[In our issue of May 30th we published some sketches and a brief description of the Hannover biplane, promising to return to this machine in more detail later. We have now received the following official report on the machine, which will therefore take the place of the description which we had intended to prepare. The report will not, perhaps, be found quite so thorough as those which we ourselves have hitherto prepared, but we think that in spite of this all the main features have been dealt with. - ED.]
THIS machine was brought down by anti-aircraft fire near Lestrem, on March 29th, 1918. As will be seen from the photographs, it is of highly characteristic design, and possesses numerous features of interest.
On labels protected by celluloid, and on the upper surfaces of the wings and fuselage, are identification marks with the date 15/2/18, showing that this machine is of recent construction.
Generally speaking, the construction is of wood throughout, steel being used sparingly, except in the interplane struts, landing chassis struts, centre section and some details of the tail.
Judged by contemporary British standards of design, the Hannoveraner biplane reaches a fairly high level, the construction throughout being sound, and the finish quite good.
The performance of the machine is not by any means bad.
The leading particulars of the machine are as follows :- Weight empty, 1.732 lbs.; total weight, 2,572 lbs.; area of upper wings, 217.6 sq. ft.; area of lower wings, 142.4 sq. ft.; total area of wings, 360 sq. ft.; loading per sq. ft. of wing surface, 7.29 lbs.; area of aileron, each, 16.4 sq. ft.; area of balance of aileron, 1.6 sq. ft.; area of top plane of tail, 10 sq. ft.; area of bottom plane of tail, 19.2 sq. ft.; total area of tail plane, 292 sq. ft.; area of fin, 6.5 sq. ft. approx.; area of rudder, 6.4 sq. ft.; area of elevators, 22.0 sq. ft.; horizontal area of body, 53.2 sq. ft.; vertical area of body, 91.6 sq.ft.; total weight per h.p., 14.3 lbs. per h.p.; crew, pilot and observer; armament, 1 Spandau firing through propeller, 1 Parabellum on ring mounting; engine, Opel Argus, 180 h.p.; petrol capacity, 37 1/4 gallons; oil capacity, 3 1/4 gallons.
Performance. - (a) Climb to 5,000 ft., 7 mins.; rate of climb in ft. per min., 590; indicated air speed, 68; revolutions of engine, 1,495. (b) Climb to 10,000 ft., 18 mins.; rate of climb in ft. per min., 340; indicated air speed, 65; revolutions of engine, 1,475. (c) Climb to 13,000 ft., 29 mins. 45 secs.; rate of climb in ft. per min., 190; indicated air speed, 62; revolutions of engine, 1,445.
Speed. - At 10,000 ft., 96 miles an hour; revolutions, 1,565. At 13,000, 89 1/2 miles an hour; revolutions, 1.520. Service ceiling at which rate of climb is 100 ft. per min., 15,000; estimated absolute ceiling, 16,500; greatest height reached, 14,400 in 39 mins. 10 secs; rate of climb at this height, 120 ft. per min.; air endurance, about 2 1/2 hours at full speed at 10,000 ft., including climb to this height; military load, 545 lbs.
Stability. - The machine is nose-heavy with the engine off, and slightly tail-heavy with the engine on. It tends to turn to the left with the engine on.
Controllability. - The machine is generally light on controls, except that the elevator seems rather insufficient at slow speeds. It is not very tiring to fly, and pulls up very quickly on landing.
View. - The view is particularly good for both pilot and observer. The former sits with his eyes on a level with the top plane, and also enjoys a good view below him on account of the narrow chord of the lower plane.
Wings. - The general arrangement of the Hannoveraner wings is somewhat reminiscent of the R.E.8, except, of course, that the bottom planes have no ailerons. The upper wings are practically flat in end elevation, but the lower have pronounced dihedral angles of 2.7 deg., and are set with a positive stagger of 2 ft. 7 1/2 ins. The chord of the upper plane is 5 ft. 10 3/4 ins., and that of the lower plane 4 ft. 3 ins. In flying position, therefore, the trailing edge of the lower plane is slightly in advance of that of the upper plane. The angles of incidence marked on the manufacturer's rigging diagram, which is fixed to the side of the fuselage, and stamped on the fabric of the wing, are as follows :-Lower wings, 5 1/2 deg. at fuselage, 5 deg. at struts; top wings, 5 deg. throughout.
The lower wings are carried direct from the bottom edge of the fuselage, the roots of the upper planes being carried on a rigidly constructed centre section, which embraces the radiator and the gravity feed petrol tank. The rearward portion of the centre section is cut away immediately over the pilot's seat, and at this point the wing is about 1 ft. above the upper surface of the fuselage. The lower plane has no very pronounced wash-out, but this feature is more noticeable in the upper plane, and is enhanced by the design of the ailerons, the tips of which are set at a slightly negative angle. This gives the characteristic German appearance to the aeroplane when seen in flight. In contrast with that of the majority of German aeroplanes, the wing section is rather flatter than, usual. (Fig. 1.)
In Fig. 2 is given a scale drawing of the complete rib. The spars are of the usual built-up hollow section. The attachment between the wings and the fuselage is such as to permit quick detachability in case of need. It consists of a simple ball and keyhole socket device. The spars terminate in steel boxes with horizontal slots which engage with knobs or balls mounted on the fuselage members. On entering the knobs into the slots and sliding the wings backwards for a distance of 1/2 in., the necks of the balls are engaged with the constricted part of the slots, and are then maintained in this position by vertical bolts passing through the spar boxes.
Spring doors are fitted on the lower plane to allow of the inspection of the pulleys for the aileron control wires.
Struts. - These are of plain steel tubing of 1 5/8 ins. diameter, and are fitted with wooden fairings, secured by wrappings of fabric, the final section being of fair streamline form with a length of 4 3/8 ins. and a breadth of 1 3/4 ins. The ends of the strut tubes are tapered, welded up and drilled, the method of attachment to the spars being shown in Fig. 3.
The centre section struts are streamline section, and consist of flattened steel tubes, welded together so as to form a triangulated construction. These struts are secured to the fuselage in the manner set forth in Fig. 4. At their upper extremities, as shown in Fig. 5, they terminate in ball and socket joints, the box portions of which are carried on the spars of the top plane centre section.
With regard to the strut sockets used in other positions, and as illustrated in Fig. 3, these are of a standardised design, except the tubular socket itself, which is adapted to be welded on to the spar plate at different angles according to circumstances.
The main lift wires are taken from the strut sockets of the upper plane to the bottom edge of the fuselage, and are there authored to stout clips, of the type shown in Fig. 6. These clips are bent round the bottom of the fuselage longeron, and have a horizontal extension carrying a steel strap which passes right across the fuselage, immediately under its wooden transverse member.
Fuselage. - This is of approximately rectangular section amidships, tapering off to oval near the tail. It consists of the usual wooden framework of four longerons reinforced and covered in with three-ply wood 1/16 in. thick. This is applied in square panels in similar manner to that which obtains in the Albatros machines, but in this case is covered all over with doped fabric.
Wiring is absent from this construction, but the fuselage is transversely braced internally with wooden diagonal members, which, however, occur at only one point about half-way between the gunner's cockpit and the tail. This is shown in Fig. 7.
At the tail end of the fuselage holes are cut in the coveting to facilitate lifting the tail, so that the weight of the machine is carried on the longerons. In Fig. 7 can be seen at the extreme end of the fuselage a strut fastened to cross members. This continues to the top of the fin and forms an attachment for the upper plane of the tail.
The depth of the fuselage at the gunner's cockpit is unusually great, being 4 ft. 7 ins., with a width of 3 ft. 2 ins. Forward of this point the fuselage is sharply tapered in the vertical plane, but more gently faired off in the horizontal plane.
The engine is only partially covered in.
Between the pilot's and gunner's cockpit is fitted a stout cross member of steel tube.
Undercarriage. - This is of the usual design, consisting of tubular steel struts with wooden fairings wrapped on with tape. The forward struts are attached to the fuselage by a joint which also acts as the anchorage of the forward flying wires, and for the undercarriage cross bracing cables. The turnbuckles of the latter are furnished with spherical heads which are carried in cups pressed out of the lug plate. The actual junction of the strut and the socket is formed by a ball and cup.
The shock absorbers are triple coil springs, enclosed in a fabric covering.
The wheels are 760 by 100, and are covered in with fabric discs in the usual manner.
Engine Mounting. - The engine is carried on I-section bearers bracketted to vertical members of the forward part of the fuselage. One of these bearers is visible through the inspection door, which is shown open in Fig. 5.
Engine. - The motor fitted is a 180 h.p. Opel, upon which a separate report is issued. It is of standard 6-cylinder vertical type, and is designed on the accepted German lines.
Empennage. - One of the most characteristic features of the Hannoveraner machine is the biplane tail, of which the span is unusually small. The upper plane is mounted on the fin, which in itself forms a streamline extension of the rearward portion of the fuselage. As in previous German types which have been described, the merging of the stream into the fin is very neatly carried out. The object of the biplane tail is evidently to mitigate the masking effect of the tail on the movable gun, as there is evidence that the gunner habitually fires through the tail at hostile machines approaching from behind. The bottom plane is covered with 1/16 in. three-ply wood throughout, and the top plane with fabric. The fin is likewise covered with three-ply on which is applied a layer of fabric. Both upper and lower planes are fixed, there being no means of tail adjustment provided.
Whereas the upper plane is flat and thin, the bottom plane is heavily cambered top and bottom. It is fitted with barbs to prevent mechanics lifting the machine by the tail. An inclined interplane strut is fitted on either side of the fin. This is of steel tube of approximately streamline section, and each cell so formed is furnished with cross bracing wires. That portion of the fin which extends below the fuselage is used to provide the mounting for the tail skid, the general arrangement of the tail being shown in photograph D. The tail skid is not provided with a swivel mounting, but has a solid metal shoe of good dimensions with convex underside, allowing the skid to sideslip in answer to the rudder when running on the ground. It is sprung with elastic bands at its forward end.
The elevators are worked together, and are coupled up as shown in Fig. 8. It will be noticed that this arrangement, in which the upper and lower links are brought to separate pins, and not to a single pin, results in the elevators being worked through slightly different angles, but this differentiation is in practice, of course, inappreciable.
Control. - The ailerons are fitted to the top plane only. They measure 7 ft. 9 1/2 ins. long, and project at each side about 7 ins. beyond the fixed wing tip. The framework on which they are built consists of light steel tubing. The maximum chord of the aileron is at the wing tip, where it reaches 1 ft. 11 ins., having a minimum chord of 1 ft. 6 ins. at its inner end. A balancing area of approximately 1 sq. ft. is provided forward of the aileron pivot. The aileron control embodies a curved lever passing through a slot in the main plane immediately ahead of the aileron. From each end of this lever, which forms part of the aileron framework, wires are taken to pulleys on the lower wing, whence they proceed in guides behind the leading wing spar to the control stick, to which they are attached in such a manner that each aileron is actuated postively by a direct pull from the control stick, and not through the medium of a balancing wire.
The control lever is of a type not previously found in German models. As shown in Fig. 9, it is provided with two inclined wooden handles, one of which, on the left side, is not fixed, but is carried by a tubular sleeve which is capable of rotation around the control stick tube. By moving this lever circumferentially, the throttle is controlled by means of a crank which is carried at the bottom end of the control stick sleeve. The throttle lever is fitted with a ratchet operated by a grip lever, as shown in the sketch.
The elevators are controlled by the usual double-ended cranks, the wires being carried down the fuselage in small tubular guides.
The rudder bar is built up of welded sheet steel, and is fitted with the usual heel rests. It is placed forward of the bulkhead, which provides a dashboard in front of the pilot's seat, and on each side, as shown in sketch, Fig. 10, sheet metal casings are provided for the pilot's feet. This construction, which is, of course, dictated by considerations of body length, has the advantage of preventing the draught which usually comes from the underside of toe pilot's cockpit.
The rudder control wires pass over pulleys on either side of the base of the cockpit, and thence down the fuselage to the rudder.
Engine Control. - The main throttle control is as described above. In addition, however, there is an independent throttle control, consisting of a push rod carried through an opening on the dashboard. Either control can be used, independently.
The ignition advance lever is similarly arranged, and consists of a rod thrust through a plate on the dashboard and terminating in a small fibre handle.
Radiator. - In accordance with the usual practice characteristic of German machines of this type, the radiator forms a part of the upper plane centre section. It has an area of 27 ins. by 16 ins. and consists of the usual oval section horizontal tubes.
Underneath the radiator and attached to the underside of the centre section is a circular grooved ring. This is evidently intended to carry a semicircular disc which is pivoted in a bearing fixed in the side of the radiator, and the object of which is to act as a controllable radiator shutter.
Petrol System. - The main petrol tank has a capacity of 30 gallons, and is fitted under the pilot's seat. It is circular in section. On the left-hand side of the top plane centre section close beside the radiator is a subsidiary tank, feeding by gravity to the carburettor. This is used for starting-up purposes. On its underside it carries a simple form of level indicator.
The main tank feeds the carburettor by air pressure, which is normally .25 gr. per sq. cm.
A hand air pump is mounted on the right-hand side of the pilot's cockpit, and, as shown in sketch. Fig. 11, is fitted with a long handle so as to be worked by either the pilot or the observer.
The main tank is furnished with a Maximall petrol level gauge, employing the principle of a float operating a dial by a cable passing over pulleys and enclosed in a sealed piping system. Provision is made for filling the gravity tank from the main tank by means of a semi-rotary hand pump mounted on the left side of the pilot's seat. Taps are arranged so that the carburettors can be fed from either-tank.
Oil. - This is contained in a tank on the starboard side of the engine. A glass level gauge is built into the side of the tank, and the covering of the fuselage is cut away at this point so that the oil level is easily visible.
Wireless. - No wireless fittings were found in this machine, but it is adapted to take the apparatus when required.
On the rear end of the engine crankshaft is a driving pulley, which can be brought into action by a clutch operated from the observer's seat. A bracket fitted on the port side of the engine over the rudder bar is evidently intended to carry the dynamo. The latter would also provide current for heating, plugs for this purpose being arranged conveniently to both pilot and observer.
Observer's Cockpit. - The observer is provided with a spring-up folding seat, which is so low, that when seated the observer has his head level with the gun mounting. A sketch of this seat is given in Fig. 12.
Provision is made for the use of a camera through a hole in the bottom of the cockpit. This is normally covered by a sliding panel, which is operated by a return wire running over a pulley. The label shown in Fig. 13 carries the following inscription :-
"This machine is arranged for photographic utensils (apparatus, implements, &c, not camera) of the photographic department. The cross tubes in the observer's cockpit low down in front are easily taken down."
The clips for holding these cross tubes are shown in Fig. 13.
A small board about 12 ins. square can be let down from the back of the pilot's seat for writing purposes, and shuts up out of the way when not required.
Clips are provided for carrying maps, &c.
On the right-hand side of the observer's cockpit is a small pull lever, shown in Fig. 14. In its normal position this rod projects through the side of the fuselage and supports on its outside the hinged bottom of a series of metal pockets, made as shown in Fig. 15. It is not quite clear what purpose is answered by this fitting. Whatever the pockets contain would be simultaneously discharged on pulling the lever.
Instruments. - An air speed indicator of the revolving anemometer type, by Morell, of Leipsic, is fitted on the forward left-hand wing strut, where it is readily visible to both the pilot and the observer.
With this exception, the instruments fitted on the machine, comprising engine revolution counter, compass, barometer, &c, are all of standard type.
Propeller. - This is stamped 180 P.S. Argus. It is composed of laminations alternately ash and some species of soft pine.
Fabric and Dope. - Both appear to be of good quality, and are up to the usual German standard.
Camouflage. - As will be seen from the photographs, the main planes are camouflaged with the usual mosaic of colours, yellow, green, pink and blue. These colours are dyed into the fabric before doping, and a similar decoration is painted on the fabric of the fuselage, which is generally dark-greenish in colour.
Armament. - The armament consists of a Spandau gun firing forward through the propeller under the control of the pilot, and a movable gun on a wooden mounting under the control of the observer. The fixed gun is placed close to the exhaust ports of the engine. The mounting of the movable gun is clearly-shown in photograph F, and in Fig. 16.