De Havilland Tiger Moth
The de Havilland DH.82 Tiger Moth is a 1930s British biplane designed by Geoffrey de Havilland and built by the de Havilland Aircraft Company. It was operated by the Royal Air Force and other operators as a primary trainer aircraft. In addition to the type's principal use for ab initio training, the Second World War had RAF Tiger Moths operating in other capacities, including maritime surveillance and defensive anti-invasion preparations; some aircraft were outfitted to function as armed light bombers.
The Tiger Moth remained in service with the RAF until it was replaced by the de Havilland Chipmunk during the early 1950s. Many of the military surplus aircraft subsequently entered into civilian operation. Many nations have used the Tiger Moth in both military and civilian applications, and it remains in widespread use as a recreational aircraft. It is still occasionally used as a primary training aircraft, particularly for pilots wanting to gain experience before moving on to other tailwheel aircraft. Many Tiger Moths are now employed by companies offering trial lesson experiences.
Design and development
Origins
Geoffrey de Havilland, the company's owner and founder, had sought to produce a light aircraft superior to two of his previous designs, the de Havilland Humming Bird and de Havilland DH.51. From earlier experience, de Havilland knew the difficulty and importance of correctly sizing such an aircraft to appeal to the civilian market, such as touring, trainer, flying club, and private aviation customers; the firm had great success with a scaled-down version of the DH.51, the de Havilland DH.60 Moth.The first aircraft to bear the name Tiger Moth was the de Havilland DH.71 Tiger Moth. De Havilland had developed successively more capable Gipsy engines, and the company had produced the new low-winged monoplane aircraft to test them. Improvements made on the Tiger Moth monoplane were incorporated into a military trainer variant of the DH.60 Moth, the DH.60T Moth – the T standing for both 'Tiger' and 'Trainer'.
The DH.60T Moth had several shortcomings, thus was subject to several alterations, such as the adoption of shortened interplane struts to raise the wingtips after insufficient ground clearance was discovered while it was undergoing trials at RAF Martlesham Heath. As a result of the Martlesham trials, a favourable report for the type was produced, which in turn led to the type soon being formally adopted as the new basic trainer of the Royal Air Force. A single prototype, designated the DH.82 Tiger Moth, was ordered by the British Air Ministry under Specification 15/31, which sought a suitable ab initio training aircraft.
One of the main changes from the preceding Moth series was improved 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's 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 same centre of lift. Other changes included a strengthened structure, fold-down doors on both sides of the cockpit, and a revised exhaust system.
On 26 October 1931 the first 'true' Tiger Moth, the prototype E6, made its maiden flight at Stag Lane Aerodrome, Edgware, London, flown by de Havilland Chief Test Pilot Hubert Broad. Shortly thereafter construction of the first 35 production aircraft for the RAF, designated K2567-K2601, began following the issuing of Specification T.23/31; in addition two float-equipped seaplanes, S1675 and S1676, were built according to Specification T.6/33.
Design
The de Havilland DH.82 Tiger Moth is a single-engined, biplane, taildragger aircraft with two seats in tandem configuration. It was developed principally to be used by private touring customers as well as for pilot instruction for both military and civilian operators. It is typically powered by a de Havilland Gipsy III 120 hp engine; later models are often fitted with more powerful models of this engine, while some have been re-engined by third-party companies.One characteristic of the Tiger Moth design is its differential aileron control setup. The ailerons on a Tiger Moth are operated by an externally mounted circular bell crank, which lies flush with the lower wing's fabric undersurface covering. This circular bell crank 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 bell crank'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 it required positive and prompt control movements. Some instructors preferred these flight characteristics because of the effect of "weeding out" the inept student pilot.
Production
The Tiger Moth quickly became a commercial success, and examples were sold to more than 25 air forces. In addition to the military demand, aircraft were also produced for the civilian market. At one point, the flow of orders for the Tiger Moth effectively occupied almost the entirety of de Havilland's capacity to manufacture aircraft, and little capacity could be spared to accommodate domestic customers. In 1932, de Havilland also developed an affordable air taxi from the Tiger Moth, using many of the main components of the former with a new plywood fuselage seating four people in an enclosed cabin; it was marketed as the de Havilland Fox Moth. Following the end of all manufacturing, third parties occasionally rebuilt Tiger Moths to a similar configuration to the Fox Moth, such as the Thruxton Jackaroo.In late 1934, 50 Tiger Moths of a more refined design, sometimes referred to as the Tiger Moth II, were delivered to the RAF; these aircraft adopted the de Havilland Gipsy Major engine, capable of generating 130 HP, and the use of plywood decking on the rear fuselage in place of fabric. Throughout the period 1934–1936, production activity was centred upon meeting the demand for military trainers, including several contracts having been placed by the RAF to Specification T.7/35, along with export orders by seven overseas operators. Civil examples were also being produced at this time, both for British private customers and to export customers in countries such as Ceylon, Greece, Lithuania, Rhodesia, Peru, and Switzerland.
After 1936, the gradual rate of acceleration of Tiger Moth manufacturing had reached the point where production capacity finally became able to exceed the demands from military customers alone. By the outbreak of the Second World War a total of 1,424 Tiger Moths had been completed by both domestic and overseas manufacturing efforts. In 1941 de Havilland transferred principal manufacturing activity for the Tiger Moth from its Hatfield factory to Morris Motors Limited at their facility in Cowley, Oxford.
In 1945, British Tiger Moth production was ended; by this point, Morris Motors had completed a total of 3,433 Tiger Moths.
Overseas manufacturing of the type commenced in 1937; the first such overseas builder was de Havilland Canada at its facility in Downsview, Ontario. In addition to an initial batch of 25 Tiger Moths that were built for the Royal Canadian Air Force, the Canadian firm began building fuselages, which were exported to the UK for completion. Canadian-built Tiger Moths featured modifications to better suit the local climate, along with a reinforced tail wheel, hand-operated brakes, shorter undercarriage radius rods, and the legs of the main landing gear legs being raked forwards as a safeguard against tipping forwards during braking. In addition, the cockpit had a large sliding canopy fitted along with exhaust-based heating; various alternative undercarriage arrangements were also offered. By the end of Canadian production, de Havilland Canada had manufactured a total of 1,548 of all versions, including the DH.82C and American Menasco Pirate-engined variants known as the Menasco Moth; this also included 200 Tiger Moths that were built under wartime United States Army Air Forces Lend-Lease orders, which were designated for paperwork purposes as the PT-24, before being delivered onwards to the RCAF.
Additional overseas manufacturing activity also occurred, most of which took place during wartime. de Havilland Australia assembled an initial batch of 20 aircraft from parts sent from the United Kingdom prior to embarking on their own major production campaign of the DH.82A, which resulted in a total of 1,070 Tiger Moths being constructed in Australia. In late 1940, the first Australian-assembled Tiger Moth conducted its first flight at Bankstown, Sydney. Most Australian aircraft were delivered to the Royal Australian Air Force, but several batches were exported, including 18 for the USAAF and 41 for the Royal Indian Air Force.
In New Zealand, 132 Tiger Moths were completed by de Havilland Aircraft of New Zealand; 23 were built in Sweden as the Sk.11' by AB Svenska Järnvägsverkstädernas Aeroplanavdelning, 91 were built in Portugal by OGMA, and another 38 in Norway by Kjeller Flyfabrikk in addition to a large number of aircraft that were assembled from kits shipped from the UK.
Operational history
Introduction
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 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. During the prewar years, increasing numbers of Tiger Moths were procured for the RAF and by overseas customers; by 1939, nearly 40 flying schools operating the type had been established, nine of which operated civilian-register models, as well.From 1937 onwards, the Tiger Moth was made available to general flying clubs, production having been previously occupied by military customers. The type was used to replace older aircraft in the civilian 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 to meet the wartime demand for trainer aircraft.