Sopwith Camel

The first one, designated F.1/1 and named “Taper Wing” had tapered wings. The wing cell had wide single struts. Upper planes were joined to the wing canopy with a small cutout for better visibility. The guns’ breeches had a different, more flat enclosure. A new, higher-rated 130-hp Clerget 9B 130 rotary was the power plant. This aircraft had been expected to be more maneuverable and have a greater level-flight speed. It turned out, though, that requiring much more labor to build (e.g. Every wing rib was different), it offered flying qualities not much better than those of the original model. The lifting surface load, minimum and landing speed were all higher compared to the latter machine.
Considering all the pros and cons of the construction, it was abandoned, even though the British aviation committee recommended in Dec 1917 that further four examples be built and developed (they were to be named the Sopwith 4F Taper Wing Camel). On the analysis we have mentioned, the old solutions tried with the F.1 were restored, which resulted in the F.1/2 prototype being the direct successor of the pre-prototype. This aircraft had been ordered by the RNAS and serialed N517.
It did not differ much from the F.1. Its upper wing of several sections had a wing canopy with a cutout for better visibility. The breech hump was similar to that used on the F.1 but had a small celluloid windscreen fitted to it. The F.1/2 was first flown on Feb 26, 1917 at Brooklands. After factory tests it was sent to RNAS base at Dunkirk for operational tests e.g. with 9 Sqn (early May), 11 Sqn (June). There the aircraft underwent comparison tests against the Nieuport (Lt. S. T. Edwards). It was further sent to 12 Sqn RNAS, where it was damaged. Another accident was serious enough to have the craft wrotten off on Aug 20, 1917.
On Mar 24, 1917 Martlesham Heath welcomed the third prototype, the F.1/3, with a single-piece upper wing. Originally it was propeled by the Clerget 9B engine. Later, Le Rhône 9Js of 110 hp were fitted as well as an experimental Clerget LS, which was designated Clerget 9BF, of 140 hp. This version became the model fr series production. The name Camel was invented to the very gun breech hump, reportedly by one Martlesham Heath test pilot.
In Apr 1917 at Martlesham Heath another prototype based on the F.1/2 was tested. It was intended for the RNAS and serialed N518. It featured a new A.R.1 engine of 150 hp derived from the Clerget 9B. Tests showed this prototype was evidently better than the others.

Sopwith 2F1 Camel, No. N6616, Estonian Aviation Company, pilot Captain Claude Emery, Lasnamagi airfield, June–July 1919. [Painting by Arkadiusz Wróbel]


Production series
Due to urgent demand, series production commenced prior to F.1/2 tests. Camels were soon mass-produced by the mother company as well as other companies under license. The first batches were built by: Sopwith Co Kingston 50 pcs (N6330-N6379 for RNAS), Ruston Proctor & Co., Lincoln 250 pcs (first license of May 22, 1917).
These companies could not meet the demand so license was granted to the following: William Beardmore Dalmuir; Boulton & Paul, Norwich; Britisch Caudron London; Hooper & Co. London; March, Jones & Cribbs, Leeds; Nieuport & General Aircraft London and Portholme Aerodrome, Huntingdon.
The first 50 Camels were delivered on Apr 7. In total, 48 batches were made. All production aircraft had three-section upper wings but were generally not different from the F.1/3. The entire order volume was 5,697 machines and about as many were indeed built. As always, these data can differ from other sources due to factors like various ways of counting the aircraft (e.g. prototypes, experimental and re-engineered machines) by various authorities.
The aforementioned circumstances resulted in the Camel being fitted with various rotary engines as the consequence of trying to optimize the power plant. The pre-prototype had a Clerget 9Z of 110 hp; F.1/1 a Clerget 9B of 130 hp; F.1/3 a Clerget 9B and later Le Rhone 9J of 110 hp, experimental Clerget LS of 140 hp (later designated Clerget 9Bf). The requirements to be met by the constructions (and probably also other, non-technical, reasons) resulted in RFC aircraft being fitted with Clerget 9Bs and RNAS machines usually featuring Bentley BR 1s.
The licensed Clerget 9B was an unreliable unit, losing power after about 10-15 hrs of running. The consequence was a dramatic decrease in speed, particularly affecting the rate of climb. E.g. two production machines tested in Apr 1917 at Dover were unable to climb to 3,050 m in 13 minutes, whereas the prototype with a weaker engine did in 6 minutes and 50 seconds! This behavior was investigated and revealed original French Clerget 9Bs were much more durable than licensed British ones, the latter being affected by the speedy loss of power. Further examination revealed timing gear failures emerging after a short running time, which required constant repairs and tuning in order to keep the engine power. As Camels’ operations confirm, squadron mechanics somehow coped, but firstly, it was not the solution, and secondly, the defects reappeared.
It seems that wartime conditions prevented maintaining the quality required by engine production. This was the reason for looking for other constructional and technological solutions. The N518 aircraft was fitted with an engine newly engineered by an RNAS engineer, Wilfred O. Bentley (famous car designer), designated AR 1 (Admiralty Rotary) rated at 150 hp. It was a derivative of the Clerget 9B, with cylinders featuring aluminum cooling ribs and steel cylinder liner. Designated BR 1 (Bentley Rotary), it was one of the best 9-cylinder rotary constructions used on the first Camels of the RNAS at the western front.
All in all, rotary engines and their supporting installations used as power plants for Camels were the cause of many troubles, their many types and modifications used on production aircraft making it still worse. To bring some order into the state of affairs, Gen. Trenchard (RFC commander) ordered on Dec 9, 1917 that production machines be fitted with the lower-rated 9-cylinder Le Rhône 9J of 110 hp, which ensured a better rate of climb for the Camel than the Clerget 9B. Later production aircraft were fitted with Clerget 9Bfs of a greater piston stroke, nominal power of 140 hp and maximum power of 160 hp, thus a little more than Bentleys. Later, all the earlier built Camels were to be re-engined, which at French units began only in Apr 1918.
Another almost constant trouble was insufficient engine deliveries. The British industry delivered only 2,000 Clergets in 1917 and over 2,000 more needed to be bought in France. On the other hand, the much better Bentleys had been by the end of 1917 built in a quantity of only 270.
Production Camels’ engines usually worked with Lang propellers of 2.59 m in diameter. […]

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