The de Havilland DH.82 Tiger Moth is a 1930s biplane designed by Geoffrey de Havilland and was operated by the Royal Air Force (RAF) and others as a primary trainer. The Tiger Moth remained in service with the RAF until replaced by the de Havilland Chipmunk in 1952, when many of the surplus aircraft entered civil operation. Many other nations used the Tiger Moth in both military and civil applications, and it remains in widespread use as a recreational aircraft in many countries. It is still occasionally used as a primary training aircraft, particularly for those pilots wanting to gain experience before moving on to other tailwheel aircraft, although most Tiger Moths have a skid. Many are now employed by various companies offering trial lesson experiences. Those in private hands generally fly far fewer hours and tend to be kept in concours condition. The de Havilland Moth club founded 1975 is now a highly organized owners' association offering technical support and focus for Moth enthusiasts.
Design and development
The Tiger Moth trainer prototype was derived from the DH 60 de Havilland Gipsy Moth in response to Air Ministry specification 13/31 for an ab-initio training aircraft. 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. 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 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.
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.
Canadian DH.82C Tiger Moth showing characteristic canopy
The RAF ordered 35 dual-control Tiger Moth Is which had the company designation DH 82. 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 Morris Motors LImited 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 manoeuvre could easily cause the aircraft to stall or spin.
A 1944-built Queen Bee in 2008.
A radio-controlled gunnery target version of Tiger Moth appeared in 1935 called the DH.82 Queen Bee; it used a wooden fuselage based on that of the DH.60 Gipsy Moth (with appropriate structural changes related to cabane strut placement) with the wings of the Tiger Moth II. There were nearly 300 in service at the start of the Second World War. It is believed the name "Drone" derived from "Queen Bee". These aircraft retained a normal front cockpit for test-flying or ferry flights, but had a radio-control system in the rear cockpit that operated the controls using pneumatically driven servos. Four-hundred were built by de Havilland at Hatfield, and a further 70 by Scottish Aviation.
De Havilland Canada in Downsview manufactured 1,548 of all versions including the DH.82C and Menasco-engined variants known as the Menasco Moth. The de Havilland Canada operation also built 200 Tiger Moths to USAAF Lend-Lease orders, which were designated for paperwork purposes as the PT-24 before being delivered to the Royal Canadian Air Force. de Havilland Australia assembled 20 aircraft from parts sent from the United Kingdom before embarking on a major production campaign of their own of the DH.82A, which resulted in a further 1,070 being built locally. Additionally, 23 were built in Sweden as the Sk.11 by AB Svenska Järnvägsverkstädernas Aeroplanavdelning, 91 were built in Portugal by OGMA, 38 in Norway by Kjeller Flyfabrikk (some sources say 37 so the first may have been assembled from a kit) and 133 were built in New Zealand by de Havilland Aircraft of New Zealand in addition to a large number of aircraft assembled from kits shipped from the UK.
In December 1939, owing to a shortage of maritime patrol aircraft, six flights of Tiger Moths were operated by RAF Coastal Command for surveillance flights over coastal waters, known as "scarecrow patrols". The aircraft operated in pairs and were armed only with a Very pistol. The intention was to force any encroaching U-boat to dive; one aircraft would then remain in the vicinity while the other would search for a naval patrol vessel which could be led back to the spot. Because they were not radio equipped, each aircraft also carried a pair of homing pigeons in a wicker basket to call for help in case of a forced landing at sea. A 25 pound (11.5 kilogram) bomb was sometimes carried, but there is no record of one being dropped in action.