De Havilland Canada DHC-1 Chipmunk
The de Havilland Canada DHC-1 Chipmunk is a tandem, two-seat, single-engined primary trainer aircraft designed and developed by Canadian aircraft manufacturer de Havilland Canada. It was developed shortly after the Second World War and sold in large numbers during the immediate post-war years, being typically employed as a replacement for the de Havilland Tiger Moth biplane. The type certificate of the aircraft is now owned by the De Havilland Canada founded in 2019.
The Chipmunk was the first postwar aviation project conducted by de Havilland Canada. It performed its maiden flight on 22 May 1946 and was introduced to operational service that same year. During the late 1940s and 1950s, the Chipmunk was procured in large numbers by military air services such as the Royal Canadian Air Force, Royal Air Force, and several other nations' air forces, where it was often utilised as their standard primary trainer aircraft. The type was produced under licence by de Havilland in the United Kingdom, who would produce the vast majority of Chipmunks, as well as by OGMA in Portugal. The type was slowly phased out of service beginning in the late 1950s, although in the ab initio elementary training role, this did not happen in the Royal Air Force until 1996, when it was replaced by the Scottish Aviation Bulldog.
Many Chipmunks that had been in military use were sold to civilians, either to private owners or to companies, where they were typically used for a variety of purposes, often involving the type's excellent flying characteristics and its capability for aerobatic manoeuvres. More than 70 years after the type having first entered service, hundreds of Chipmunks remain airworthy and are in operation around the world. The Portuguese Air Force still operates six Chipmunks, which serve with Esquadra 802, as of 2018. The aircraft is named after the chipmunk, a small rodent.
Development
Origins
Immediately following the conclusion of the Second World War, there was a desire within Canadian aviation circles to take advantage during the peace years of the recently expanded aircraft manufacturing industry which had been rapidly built up in Canada. Out of this desire, it was decided to embark on developing aircraft which would replace designs rendered obsolete by the rapid advances made during the war in the aviation field. One such company, de Havilland Aircraft of Canada Ltd, was interested in developing its own aircraft designs, and chose to focus on producing a contemporary aircraft for pilot training, specifically intending for the envisioned type to serve as a successor to the de Havilland Tiger Moth biplane trainer, which had been produced by the thousands before and during the Second World War, and saw military service with a number of nations in that conflict., a Polish pre-war engineer, served as the principal designer and led the design team in the development of the new aircraft, which became known as the Chipmunk. He designed a cantilever monoplane that incorporated numerous advances over typical trainer aircraft then in widespread service. These included an enclosed cockpit complete with a rear-sliding canopy, and various aerodynamic features to manage the aircraft's flight performance. Strakes were fitted to deter spin conditions and stall breaker strips along the inboard leading edges of the wing ensured that a stall would originate in this position as opposed to the outboard section. The Chipmunk would become the first indigenous aircraft design to be produced by de Havilland Canada.
The Chipmunk prototype, CF-DIO-X, first flew on 22 May 1946 at Downsview, Toronto, piloted by Pat Fillingham, a test pilot who had been seconded from the parent de Havilland company. The prototype was powered by a de Havilland Gipsy Major IC air-cooled inverted engine, this was replaced on the production version of the Chipmunk by a de Havilland Gipsy Major 8 engine.
Production
de Havilland Canada constructed the type at its factory in Downsview, Toronto, Ontario, where it produced 217 Chipmunks during the 1940s and 1950s, the final example of which having been completed during 1956. In addition, 1,000 Chipmunks were produced under licence in the United Kingdom by de Havilland; manufacturing was initially performed at the company's facility at Hatfield Aerodrome, Hertfordshire; production was later transferred to their factory at Hawarden Aerodrome, Broughton near Chester. A further 66 Chipmunks were licence-manufactured in Portugal by OGMA, at Alverca from 1955 to 1961 for the Portuguese Air Force.Both British-built and early Canadian-built Chipmunks are notably different from the later Canadian-built RCAF/Lebanese versions. The later Canadian-built aircraft were fitted with a bubble canopy, which replaced the multi-panelled sliding canopy that had been used upon early Canadian-produced Chipmunks, along with all of the Portuguese and British-built aircraft. On the early-built canopy, the rearmost panels intentionally bulged in order to provide the instructor's position with superior visibility. British-built Chipmunks also differed by a number of adjustments to suit the expressed preferences of the RAF. These included the repositioning of the undercarriage legs, anti-spin strakes, landing lights, and an all-round stressed airframe.
At one point, work was being conducted on a derivative of the Chipmunk which featured an extensive cabin modification to accommodate a side-by-side seating arrangement; the aircraft, which was referred to as the DHC-2, ultimately remained unbuilt. The DHC-2 designation was subsequently reallocated to the company's next product, the DHC-2 Beaver.
Design
The de Havilland Canada DHC-1 Chipmunk is a two-seat, single-engine aircraft that has been heavily used as a primary trainer aircraft. The basic configuration of the aircraft included a low-mounted wing and a two-place tandem cockpit, which was fitted with a clear perspex canopy covers the pilot/student and instructor/passenger positions and provided all-round visibility. The Chipmunk uses a conventional tailwheel landing gear arrangement and is fitted with fabric-covered flight control surfaces; the wing is also fabric-covered aft of the spar. In terms of handling, the Chipmunk exhibited a gentle and responsive flight attitude. Early production aircraft were only semi-aerobatic, while later production models were almost all fully aerobatic.The structure of the Chipmunk makes heavy use of metal, the majority of the airframe being composed of a stress-skinned alloy; this allowed the adoption of thinner wings and consequently provided for increased performance as well as a greater degree of durability. Numerous features were incorporated so that the type could better perform as a trainer, including hand-operated single-slotted wing flaps, anti-spin strakes, disc brakes on the wheeled undercarriage, a thin propeller composed of a solid lightweight alloy, the adoption of an engine-driven vacuum pump in place of external venturi tubes to power cockpit instrumentation, electric and Coffman cartridge engine starters as alternative options, cockpit lighting, onboard radio system, and an external identification light underneath the starboard wing.
In civilian service, individual aircraft would often be modified. Examples of these adaptations include extensive modifications that enabled it to perform competitive aerobatics, for which aircraft are often re-engined and fitted with constant speed propellers and inverted fuel systems; larger numbers of Chipmunks have been tasked as dedicated glider tows. It has become commonplace for Chipmunks used as such to be re-engined, often using the Lycoming O-360.
Operational history
United Kingdom
The Royal Air Force had been one of the operators to quickly take notice of the new Canadian trainer, and encouraged its formal evaluation with an eye towards procuring it. Accordingly, a total of three Chipmunk aircraft were transported to the United Kingdom, where they underwent an evaluation by the Aeroplane and Armament Experimental Establishment at RAF Boscombe Down, Wiltshire. Based upon this favourable evaluation, the British Air Ministry proceeded to formulate and release Air Ministry specification T.8/48 around the type as a replacement for the de Havilland Tiger Moth biplane then in use. This specification was also contested by the rival Fairey Primer, which lost out to the Chipmunk and ultimately did not enter production.The fully aerobatic Chipmunk was ordered to serve as an ab initio trainer for new pilots. The RAF received 735 Chipmunks, which were designated in British service as the de Havilland Chipmunk T.10; these aircraft had been manufactured in the United Kingdom by de Havilland, the parent company of de Havilland Canada.
The Chipmunk T.10 initially served with Reserve Flying Squadrons of the RAF Volunteer Reserve, as well as the University Air Squadrons. During 1958, multiple Chipmunks were pressed into service in Cyprus for conducting internal security flights during the height of civil unrest during the Cyprus dispute. Eight disassembled aircraft were flown out in the holds of Blackburn Beverley transports; following their reassembly, these Chipmunks, which were operated by No. 114 Squadron, were operated for some months into 1959.
From 1956 to 1990, the Chipmunks of the RAF Gatow Station Flight were used to conduct covert reconnaissance missions by BRIXMIS over the Berlin area. A number of Chipmunk T.10s were also used by the Army Air Corps and Fleet Air Arm to conduct primary training. Notably, Prince Philip had his first flying lesson in a Chipmunk in 1952; he declared the type to be his favourite aircraft.
Until 1996, Chipmunks remained in service with Air Training Corps and the RAF Sections of the Combined Cadet Force for Air Experience Flights ; the final of these AEF flights to use the Chipmunk was No. 10 Air Experience Flight, RAF Woodvale, when they were replaced by the Scottish Aviation Bulldog. The last Chipmunks in military service are still operated by the British historic flights – the RAF Battle of Britain Memorial Flight, the Royal Navy and Army historic flights, to keep their pilots current on tailwheel aircraft. In addition, the cockpit sections of some former RAF Chipmunks have been used as ground training aids; these are colloquially known as "Chippax" trainers.
In 1995 and 1996, the RAF planned for a pair of Chipmunks to circumnavigate the northern hemisphere to establish a route for light aircraft from Europe to North America via Russia. The RAF chose the Chipmunk because of its reliability and ability to operate with minimal ground support. Modifications were made before the journey, including expanding fuel capacity and updating navigation equipment. The Chipmunks were accompanied on the journey by a support aircraft. In 1996, the RAF started the journey, but had to stop in Moscow due to forest fires in central Siberia. The RAF successfully completed the journey in 1997, flying over 64 days, visiting 62 airfields along the way. One of the two Chipmunks was added to the collection at the RAF Museum. The other belongs to a private owner, who has restored the Chipmunk to its condition during the round-the-world flight and flies it to aviation events.