H.King Sopwith Aircraft 1912-1920 (Putnam)
The designation of this large, experimental torpedo-dropping floatplane may - as has sometimes been suggested - have been a sequential one (earlier designs having supposedly been nominated A and B) or the C may have connoted Calshot, for this was the Naval air station with which the aircraft had special associations. In any case, it will be well to preface this study of the machine - to which the Service number 138 was allocated with a sketch of torpedo-dropping experiments in the months before the First World War.
Although we have the personal testimony of the Italian General Alessandro Guidoni that as early as 1912 he had been ordered to help Pateras Pescara (then a lawyer) to build a torpedo-dropper which Pescara had proposed to the Italian Navy, and that after preliminary experiments with his 'faithful Farman’ he (Guidoni) went on to build a special monoplane having two 200 hp Gnome engines in tandem and hydrofoil floats from which, in February 1914, he dropped a torpedo weighing 750 lb (340 kg) we also know that in the very same month Winston Churchill, Great Britain's First Lord of the Admiralty, said: 'The objectives of land aeroplanes can never be so definite or important as the objectives of seaplanes, which, when they carry torpedoes, may prove capable of playing a decisive part in operations against capital ships.’
In June 1914 Churchill said that the development of a 'torpedo-carrying seaplane' would greatly affect the value of 'this type of aircraft’ (presumably seaplanes generally) and added that he hoped that it would very shortly be possible for a seaplane 'to fire a 14-inch torpedo.' This weapon would be sufficient, he expected, to sink a small cruiser, a destroyer or a transport. By that time, said Churchill, torpedo-dropping had already been practised from what he called a 'mock-up machine' - adding that torpedo officers expected a high degree of accuracy, and that an order had been placed for 'a machine to carry an 18-inch torpedo.'
Well before these predictions and disclosures by Churchill - as early, it appears in fact, as the summer of 1912 a paper discussing the torpedo-dropping problem had been written by Lieut D. Hyde-Thomson and placed before the Captain of HMS Vernon (the Navy's establishment responsible for specialist training and development in all matters concerning torpedoes). At that time, or somewhat later, a particular interest in Hyde-Thomson's ideas was shown by Capt M. F. Sueter (later Rear-Admiral) Director of the Air Department of the Admiralty, which led to the application for a secret patent jointly in the names of Sueter and Hyde-Thomson - early in 1914. By that time, it is tolerably clear, Sopwith, as well as Short, were regarded as intended, or potential, builders of torpedo-dropping seaplanes; and, having regard to several contradictions respecting early British torpedo-dropping work generally, one quotes directly the following declaration by Sir Arthur Longmore:
‘I was commanding the experimental [Naval air] station at Calshot from January to September 1914, and it was there in July 1914 that for the first time a 14-in torpedo was taken into the air and dropped successfully. Indeed, I did it. The actual seaplane was a 160 Gnome Short, the preliminary experiments on the water having been carried out for some months previously in a Sopwith taxiplane, a clipped-wing seaplane. Shortly afterwards the war broke out and what may have been really only a "stunt" experiment was regarded as an operational possibility. In August 1914 a 200 h.p. Canton-Unne Sopwith seaplane regularly went into the air with a torpedo and a considerable amount of target practice was carried out…’
Sir Arthur gave the following additional facts in a letter to the present writer some years ago: 'It seems probable that confusion has arisen in some accounts of the first drop by reason of the fact that there was at Calshot at the time a Sopwith Canton-Unne taxi-plane (centre section only) which was used for developing the release mechanism and for registering the behaviour of the floats, undercarriage and general construction under taxying conditions on the water. Lieut. Robin Ross frequently handled this taxiplane. Lieut. Hyde-Thomson was specially appointed to Calshot to take part in the development of the torpedo carrying ... Shortly afterwards a Sopwith Canton-Unne floatplane was delivered at Calshot fitted for carrying the 900 lb. 14 in torpedo (the same as I had previously dropped). With this machine I and my other pilots frequently flew with the torpedo and did a few successful runs at a target.’
These matters having thus been presented by one of the principal figures concerned, and taking no further cogniscance of the "Sopwith Canton-Unne taxi-plane” mentioned by Sir Arthur (especially as a similarly rigged Borel floatplane has also been associated with Hyde-Thomson's early work) we may proceed to examine the Sopwith Type C - or, as a reasonable supposition, what Sir Arthur Longmore called the 'Sopwith Canton-Unne floatplane', which, although frequently associated with the year 1913, seems more properly to date from 1914.
Understandably having regard to the difficulty of lifting even a 14 in torpedo, and the early prospects for the airborne launching of one of the heavier 18 in patterns this was a large and powerful machine. Its size, in fact, is implicit in the sheer breadth and rigging of its biplane wings, which might well have been similar to those of the 'machine of 80 ft. span' mentioned in the chapter on 'Pushers and Gun Buses'. In any case, they were not only of four-bay construction, but had the additional distinction of strut-braced top-wing extensions. Strut-connected ailerons were fitted on all four wings.
The only known surviving photograph is reproduced, and it would be pointless to add the conjectural to the obvious. Certainly, the features commanding most attention (apart from the impressive size) are the powerplant installation and the gear for carrying and releasing the torpedo. The photograph shows - or at least suggests - side-mounted radiators for the 200 hp Canton-Unne (Salmson) water-cooled radial engine. Probably by reason of the name 'Canton', this engine has sometimes been described as having Swiss origins, though this is evidently not so, the two inventor patentees concerned - MM Canton and Unne - having been French, and their truly remarkable engines being products of the Societe Anonyme des Moteurs "Salmson", of Billancourt, Seine, France, or of the Dudbridge Iron Works Ltd. of Stroud, Glos, England.
A point concerning the powerplant that may be of more than trivial interest is that in the line-drawings reproduced (and prepared with the primary object of showing the torpedo-stowage on an obviously Sopwith-type aircraft more or less identifiable - except, perhaps, for the slightly staggered wings - with the Type C) the representation of the engine is apparently tentative. There could, of course , be several explanations of this; but one that instantly comes to mind is the following: Whereas the 200 hp Canton-Unne engine was normally mounted conventionally (that is, vertically) - driving the propeller directly or through a shaft (the latter apparently being the case in the Type C as shown in the photograph) - certain engines of the same family were constructed with the cylinder-axes horizontal and the crankshaft-axis vertical, the propeller then being driven at right angles by means of bevel gearing. It was contemporarily stated: 'This horizontal disposition is often adopted in dirigibles, and occasionally in large sea-planes ...".
Whatever the facts or intentions, however, the 200 hp fourteen-cylinder water-cooled radial engine of the Type C, with its shaft drive and side-mounted radiators, is certainly worthy of this special note.
In one form of torpedo gear apparently designed for the Type C (and evidently that which the line-drawings show) the projectile was to have a single-point suspension from a shackle on a longitudinal beam, and was to be steadied against swaying by fittings that eventually became known as 'crutches'. Release - effected from the pilot's seat - was to be mechanical.
Having introduced these notes on the Sopwith Type C with reference to early Italian experiments in torpedo-dropping it seems fitting to append the following:
In 1913 it was reported apparently on good authority - that three 'Sopwith type hydro aeroplanes' had been ordered by Italy; and though these were termed, in one context, as 'torpedo air-craft' it must be recognised that this particular expression was in fairly common international currency at that period to connote heavier-than-air machines of the 'fighting', 'scouting' or 'bomb-dropping' persuasion, as distinct from lighter-than-air craft. Whatever the implication, no Sopwith aircraft of any kind are known to have been supplied to Italy before the war of 1914.
Yet even so, though Erskine Childers' story The Riddle of the Sands had first been published ten years earlier, those same ten years were fraught with many mysteries of fact as well as fiction. One doubtless unrelated, but nevertheless curious, fact was that among Erskin Childers' brother-officers in 1914 was Lieut Robin Ross, earlier singled out for particular mention by Sir Arthur Longmore.
F.Manson British Bomber Since 1914 (Putnam)
Sopwith Special (No 170) & Type C
Whether or not Italian pioneering work on aerial torpedo-dropping, dating from 1912, in any way influenced the British Admiralty, has not been positively established. It is, however, recorded that a discussion paper was prepared by Lieut D H Hyde-Thomson RN in 1912, setting down suggested parameters for the use of aerial torpedoes; this was submitted to the Admiralty torpedo establishment and eventually reached Capt Murray Fraser Sueter RN (later Rear-Admiral, CB, MP) of the Air Department at the Admiralty. In 1913, as a direct result of this paper, the Admiralty invited the manufacturers Sopwith, Short and White to produce prototype torpedo-carrying seaplanes. These were to become the Sopwith Special, the Short Type 184 and the Wight Type 840 (listed chronologically - although, by means of adaptation, a Short Folder was to be the first British aeroplane to air-drop a torpedo).
Until relatively recently there has been much confusion regarding early Sopwith torpedo-carrying seaplanes, to some extent caused by surviving company records which suggest that all seaplanes ordered by the Admiralty before the First World War, and powered by the 200hp Canton-Unne fourteen-cylinder water-cooled radial engine, mounted horizontally (purchased in France, and later manufactured in Britain as the Salmson 2M.7), were referred to as Type Cs. There was certainly a Short Type C powered thus, but it was not equipped to carry a torpedo. A surviving Sopwith company photograph was captioned to illustrate a large four-bay seaplane with Canton-Unne engine as a Type C aeroplane. The accuracy of this caption had never been questioned until recent research indicated that the photograph in fact depicts the Sopwith Special, No 170, apparently designed by R J Ashfield, an aircraft intended to lift a 14in torpedo weighing 810 lb. Indeed, this was the first British aeroplane designed and built with the specific object of carrying a torpedo.
According to Sqn-Cdr Longmore, commanding NAS Calshot, No 170 arrived on or about 1 July, and was assembled within about five days. Engine runs and some taxying trials, however, disclosed that 'extensive' modifications would be needed before the aircraft would succeed in taking off with the torpedo. To begin with, it was found that the engine was not giving full power, and a new engine was fitted, but even when the torpedo was removed the aircraft still refused to take off. Thus, it was to be the Short No 121 that first took off and launched a torpedo on 28 July.
There is no doubt but that the Short Folder was a superior aircraft and, although the Sopwith Special eventually managed at least one flight with pilot (Flt-Cdr J L Travers), passenger and a full load of fuel on 7 November, it never succeeded in lifting a torpedo. At the end of that month, in a belief that No 170 might be usefully employed as a bomber, the seaplane was being fitted with an experimental bomb rack, but it is not known whether it was ever flown with this for, early in January 1915, the Canton Unne engine was being stripped down for inspection at Calshot. At about the end of April the Special was removed from RNAS charge and during the following weeks it was finally dismantled.
Unfortunately very little information of a reliable nature survives about the Sopwith Type C, other than reference to three such aircraft, Nos 157-159, in the RNAS equipment lists; these seaplanes (and the six Short Type Cs, Nos 161-166) were categorised as 'bomb-carriers' with folding wings, wireless equipment and a defensive gun. However, there is no evidence that the Sopwith Type Cs ever flew with a bomb load and, as they do not appear to have undergone trials with the RNAS at Calshot, there are no surviving records of flight trials.
Type: Single-engine, two-seat, four-bay biplane, twin-float seaplane designed to carry a torpedo.
Manufacturer: The Sopwith Aviation Co Ltd, Kingston-upon-Thames, Surrey.
Powerplant: One 205hp Canton-Unne (Salmson) fourteen-cylinder, water-cooled, radial engine mounted with crankshaft vertical and driving two-blade propeller through extension shaft and gearbox.
Dimensions: Span (upper wing) 66ft; (lower wing) 58ft; length, 36ft; wing area, 785 sq ft.
Weight: Max all-up, 4,3241b (design estimate)
Performance: No records traced.
Armament: Provision to carry one 810 lb 14in Whitehead torpedo. No gun armament. (Neither torpedo nor gun believed to have been flown)
Prototypes: Special Seaplane, No 170, first flown during September 1914. Three Sopwith Type Cs are believed to have been constructed (Nos 157-159), but no flight details have been traced.
H.King Armament of British Aircraft (Putnam)
Type C. The first British-built aeroplane designed specifically for torpedo-dropping, the Type C tractor seaplane, was built in 1914. It arrived at Calshot shortly after Sir Arthur Longmore (then Squadron Commander) had made his first torpedo-drop from a Short, and he and his pilots made drops from the new Sopwith product. It was a four-bay biplane of very large span, with overhang, and it may be wondered if the wing cellule was similar to that of No. 127. As on the A.D. 1000 the two floats were quite independent, in order to allow the torpedo to be dropped. Each float was strut-braced to the lower longerons and to the attachment points of the inner interplane struts. This arrangement probably represented the first major influence of armament on aircraft design.
M.Goodall, A.Tagg British Aircraft before the Great War (Schiffer)
Deleted by request of (c)Schiffer Publishing
P.Lewis British Aircraft 1809-1914 (Putnam)
Sopwith Torpedo Seaplane
The Torpedo Seaplane Type C was built in 1913 for the specialised task of torpedo dropping. Strut-connected ailerons were fitted to each wing-tip, and the power was provided by the 200 h.p. Salmson engine cooled by radiators on each side of the fuselage.
Flight, February 6, 1919.
THE SOPWITH MACHINES
The Torpedo Seaplane. (1914)
In 1915 the Sopwith Co. built for the Admiralty a torpedo-carrying aeroplane. This machine was of an experimental character, but is notable as having been the forerunner of the famous Sopwith "Cuckoo." It was fitted with a 200 h.p. Canton-Unne engine.