de Havilland Tiger Moth



History

The de Havilland DH.82 Tiger Moth is a single-engine biplane light aircraft. It was developed principally to be used by private touring customers as well as for pilot instruction for both military and civil operators. It was a derivative of earlier de Havilland Moth training aircraft and was designed because the Royal Air Force was dissatisfied with their existing de Havilland Moth Trainer due to poor accessibility of the front cockpit. As a service requirement, RAF crews all wore parachutes and thus accessing or exiting into either the front or the rear instructor’s cockpit of a Moth was difficult enough on the ground but unviable if one of the crew had to bail out quickly once airborne. With the potential of a large RAF order for a basic training aircraft, de Havilland re-developed the earlier DH60G Gipsy Moth. The fuselage was strengthened for service use, fitted with a Gipsy III inverted, rather than upright, engine for improved forward view, the four wings were initially swept-back nine inches, to allow easier exit from the cockpit by parachute and re-designated the DH82. The prototype dual-control DH82 Tiger Moth maiden flight was on 26 October 1931 resulting in the RAF ordering 35. Some early production models were also being purchased by civilian owners.

From the outset the Tiger Moth proved to be an ideal trainer, simple and cheap to own and maintain, although control movements required a positive and sure hand as there was a slowness to control inputs. Some instructors preferred these flight characteristics because of the effect of “weeding out” the inept student pilot

The Tiger Moth entered service at the RAF Central Flying School in February 1932. The RAF subsequently placed orders for 50 more aircraft powered by the more powerful 130 hp Gipsy Major engine I instead of the 98 hp Gipsy III, the upper wings angled back a further two inches for front cockpit access and plywood instead of fabric covered top fuselage, these modifications led to the aircraft being designated the DH82a by de Havilland and Tiger Moth II by the RAF. From 1937 onwards the Tiger Moth was made available to general flying clubs and to overseas customers; by 1939 nearly 40 flying schools operating the type had been established, nine of which operated civil-registers models as well. The type was quickly used to replace older aircraft in the civil trainer capacity, such as the older de Havilland Cirrus Moth and Gipsy Moth.

By the start of the Second World War the RAF had around 500 Tiger Moths in service. In addition, nearly all civilian-operated Tiger Moths throughout the Commonwealth were quickly impressed into their respective Air Forces in order to meet the strenuous wartime demand for trainer aircraft.

Design

One distinctive characteristic of the Tiger Moth design is its differential aileron control setup. The ailerons (on the lower wing only) on a Tiger Moth are operated by an externally mounted circular bellcrank, which lies flush with the lower wing’s fabric undersurface covering. This circular bellcrank is rotated by metal cables and chains from the cockpit’s control columns, and has the externally mounted aileron pushrod attached at a point 45° outboard and forward of the bellcrank’s centre when the ailerons are both at their neutral position. This results in an aileron control system operating with barely any travel down at all on the wing on the outside of the turn, while the aileron on the inside travels a large amount upwards to counteract adverse yaw.

Training

The Tiger Moth II became the primary trainer throughout the Commonwealth and elsewhere. It was the principal type used in the British Commonwealth Air Training Plan where thousands of military pilots got their first taste of flight in this robust little machine. The RAF found the Tiger Moth’s handling ideal for training future fighter pilots. Generally docile and forgiving in the normal flight phases encountered during initial training, when used for aerobatic and formation training the Tiger Moth required definite skill and concentration to perform well – a botched manoeuvre could easily cause the aircraft to stall or spin. From 1941 onwards all military and many civil Tiger Moths were outfitted with anti-spin strakes positioned on the junction between the fuselage and the leading edge of the tailplane, known as Mod 112; later on, the aileron mass balances were removed for improved spin recovery performance.

Elementary Flying Training Schools [EFTS] were often pre war flying schools that had been paid by the RAF to train pilots to a standard level. When war broke out they were incorporated into the RAF and expanded. However the transition was fairly simple, the core instructors often had years of experience, new instructors were easily trained and everyone was familiar with the planes both pilots and engineers.

In 1935 the RAF trained about 300 pilots a year, by August 1940 this had increased to 7,000 pilots a year. At an EFTS, a pilot would typically receive 50 hours of elementary flying training – 25 hrs dual, 25 hours solo, over a 28 week period, by June 1940, training time was reduced to 23 weeks, by August 1940 reduced further to 22 weeks. During WW2 3 EFTS were based at Watchfield, 6 EFTS at Sywell, 7 EFTS at Desford, 15 EFTS at Kingstown, 22 EFTS at Cambridge, 26 EFTS at Theale, 28 EFTS at Wolverhampton, 29 EFTS at Clyfe Pypard and 34 EFTS at De Winton, Canada.

A total of 8,868 were built were manufactured.

Tiger Moth II Specification:

Powerplant: 130 hp Gipsy Major engine
Performance: Max speed: 160 mph,
Cruise speed: 86 mph,
Ceiling height: 18,000 ft
Range: 300 miles.
Weight: Unladen: 1,200 lbs,
Max laden: 1,825 lbs.
Dimensions: Wing span: 29 feet 4 inches,
Length: 23 feet 11 inches,
Maximum height: 8 feet 9 inches.
Armament: None.
Crew: 2




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