The bubble canopy had been in use well before
Second World War; a number of experimental bubble canopy designs has been tested during the
First World War. British aircraft designers developed the
Malcolm hood, a bulged canopy, that was first adopted on the
Supermarine Spitfire and subsequently other aircraft. The British
Miles M.20 was amongst the first aircraft designs to feature a true one-piece sliding bubble canopy. Although that aircraft never went into production, the concept of the bubble canopy was later used on other British aircraft, such as the
Hawker Typhoon and
Tempest. Subsequently, Malcolm hood-style canopies were fitted to the
North American P-51 Mustang and
Republic P-47 Thunderbolt, amongst other aircraft. A well-framed version of an all-around vision canopy was also used on the
Imperial Japanese Navy Air Service Mitsubishi A6M Zero Japanese naval fighter. Different designs, with much less framing than the "Zero" hood, were used on the
Imperial Japanese Army Air Service Nakajima Ki-43 Oscar and
Nakajima Ki-84 Frank land-based fighter aircraft. The
Bell 47 helicopter was the first production helicopter certified for civilian use in the United States, and in its Model 47D version, pioneered the "soap bubble"-style canopy for light helicopters – as named by its designer,
Arthur M. Young – that it and the 47G model were to become famous for. Following after the Bell 47, various other rotorcraft have used bubble canopies, including the
Robinson R44,
Schweizer S333, and the
Mil Mi-24, the later versions of the latter possessing a distinctive tandem cockpit with a "double bubble" canopy that replaced its original angular greenhouse-style cockpit arrangement. Numerous
jet-powered fighter aircraft of the
postwar era adopted bubble canopies. One of the more prominent external differences between the ground-attack orientated
Hawker Siddeley Harrier and the later
British Aerospace Sea Harrier, a navalised fighter derivative of the former, was the adoption of an elevated cockpit within a bubble canopy, granting superior exterior visibility to the pilot. The
General Dynamics F-16 Fighting Falcon also adopted a frameless bubble canopy in conjunction with a raised and reclined seat that granted unobstructed forward and upward vision. The canopy of the F-16 comprises a single piece of
bird-proof polycarbonate; it lacks the forward bow frame found on many fighters, which is an obstruction to a pilot's forward vision. Bubble canopies were also incorporated into the
Lockheed Martin F-22 Raptor and the
Eurofighter Typhoon, both being fighters oriented towards the aerial supremacy role. Specialised aerial reconnaissance aircraft have also made use of bubble canopies. The
Edgley Optica incorporates an unorthodox fully glazed forward cabin, intended to provide a high level of exterior vision to its crew; the aircraft has a distinctive appearance due to this cabin, often being referred to as the "bug-eye". The bubble canopy has also been adopted within the
general aviation sector; the
Diamond DA42 is one such aircraft which incorporates such a canopy in some guises, typically intended for reconnaissance work. Another general aviation aircraft, the
Grob G 120, also features a relatively wide bubble-style canopy. Numerous aircraft within the general aviation category feature such canopies. ==Purpose==