The de Havilland DH 82 Tiger Moth is a 1930s biplane designed by Geoffrey de Havilland and was operated by the Royal Air Force and others as a primary trainer. The Tiger Moth remained in service with the RAF until 1952 when many of the surplus aircraft entered civil operation. Many other nations used the Tiger Moth both in military and civil applications and the ubiquitous little trainer is still in great demand worldwide as a recreational aircraft. It is still occasionally used as a primary training aircraft, although now most Tiger Moths employed in training duties are used by pilots gaining experience for "taildragger" license ratings.
Design and development
The Tiger Moth trainer prototype was derived from the DH 60 de Havilland Gipsy Moth. The main change to the DH Moth series was necessitated by a desire to improve access to the front cockpit since the training requirement specified that the front seat occupant had to be able to escape easily, especially when wearing a parachute. Access to the front cockpit of the Moth predecessors was restricted by the proximity of the aircraft's fuel tank directly above the front cockpit and the rear cabane struts for the upper wing. The solution adopted was to shift the upper wing forward but sweep the wings back to maintain the centre of lift. Bizarrely, this made the Tiger Moth (a piston-engined biplane with an 80-knot cruise speed) the RAF's first swept wing aircraft. Other changes included a strengthened structure, fold-down doors on both sides of the cockpit and a revised exhaust system. It was powered by a de Havilland Gipsy III 120 hp engine and first flew on 26 October 1931 with de Havilland Chief Test Pilot Hubert Broad at the controls.
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 45º 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 counter-act adverse yaw.
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 RAF ordered 35 dual-control Tiger Moth Is which had the company designation DH 60T. A subsequent order was placed for 50 aircraft powered by the de Havilland Gipsy Major I engine (130 hp) which was the DH 82A or to the RAF Tiger Moth II. The Tiger Moth entered service at the RAF Central Flying School in February 1932. By the start of the Second World War, the RAF had 500 of the aircraft in service and large numbers of civilian Tiger Moths were impressed to meet the demand for trainers.
During a British production run of over 7,000 Tiger Moths, a total of 4,005 Tiger Moth IIs were built during the war specifically for the RAF, nearly half being built by the Morris Motor Company at Cowley, Oxford.
The Tiger Moth became the foremost 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. Whilst 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 manouevre could easily cause the aircraft to stall or spin.
A number of modified Tiger Moths were developed for special roles. A radio-controlled target tug version of the Tiger Moth II called the DH.82B Queen Bee was built with nearly 300 in service at the start of World War II. The Fleet Air Arm operated small numbers of the Tiger Moth II, and the Queen Bee. In the aftermath of Britain's disastrous campaign in France, in August 1940, three proposals involved beach defence systems; 350 Tiger Moths were fitted with bomb racks to serve as light bombers. A more radical conversion involved the "paraslasher," a scythe-like blade fitted to a Tiger Moth and intended to cut parachutist's canopies as they descended to earth. Flight tests proved the idea, but it was not officially adopted. The Tiger Moth was also tested as a "human crop sprayer" intended to dispense Paris Green poisonous insecticide from powder dispensers located under the wings.
In Canada, de Havilland manufactured 1,523 of the DH 82C, which had a 145 hp D.H. Gipsy Major 1C engine and other modifications including a tail wheel replacing the original tail skid, a stronger undercarriage with wheels set farther forward and enclosed cockpit with a sliding canopy necessitated by the cold northern climate. The de Havilland Canada operation also supplied 200 Tiger Moths to the USAAF, which designated them the PT-24. A further 151 were built in Norway, Sweden and Portugal while 2,949 Tiger Moths were built by other countries of the British Commonwealth.
In postwar use, surplus Tiger Moths were made available for sale to flying clubs and individuals. They proved to be inexpensive to operate and found enthusiastic reception in the civil market, taking on new roles including aerial advertiser, aerial ambulance, aerobatic performer, crop duster and glider tug. They were often compared with the Stampe SV.4 famous aerobatic aircraft.
After the invention of aerial topdressing in New Zealand, large numbers of ex-Royal New Zealand Air Force Tiger Moths built in that country were converted into agricultural aircraft. The front seat was replaced with a hopper to hold superphosphate for aerial topdressing. From the mid 1950s, these topdressers were replaced by more modern types such as the PAC Fletcher, and a large number of New Zealand Tiger Moths in good flying condition then passed to enthusiasts.
Royal Navy Tiger Moths utilised as target tugs and "air experience" machines became the last military aircraft when the service purchased a batch of refurbished examples in 1956.
Tiger Moths were often modified to stand in for rarer aircraft in films. Notably, Tiger Moth biplanes were used in the crash scenes in The Great Waldo Pepper, standing in for the Curtiss JN-1.
Numerous examples of the Tiger Moth are still flying today (an estimated 250). The number of airworthy Tiger Moths has increased as previously neglected aircraft (or those previously only used for static display in museums) have been restored. A number of aircraft have been preserved as museum displays (amongst others) at the:
Specifications (DH 82A)
Data from The Tiger Moth Story
Published - July 2009
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