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.
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 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.