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Bristol Type 188

The Bristol 188 is a British supersonic research aircraft built in the 1950s.

Its length, slender cross-section and intended purpose led to its being nicknamed the “Flaming Pencil”.

In May 1960, the first airframe was delivered to the Royal Aircraft Establishment at Farnborough for structural tests, both heated and unheated, before moving on to RAE Bedford.

XF923 undertook the first taxiing trials on 26 April 1961, although due to problems, the first flight was not until 14 April 1962.

XF923 was intended to remain with Bristol for its initial flights and evaluation before turning it over to the MoA.

XF926 had its first flight, using XF923s engines, on 26 April 1963.

XF926 was given over to RAE Bedford for its flying program.

Across 51 flights, it reached a top speed of Mach 1.88 (1,440 mph : 2,300 km/h) at 36,000 ft (11,000 m).

The longest subsonic flight lasted only 48 minutes, as 70% of its fuel was needed to reach its operational altitude.

The first prototype made its first public appearance in September 1962 when it was displayed on the ground and in the air at that year’s Farnborough Air Show.

In the same year the aircraft was seen in the film Some People.

Measurements collected during testing were recorded onboard and transmitted to the ground station for recording.

The flight information transmitted meant that a “ground pilot” could advise the pilot.

The project suffered a number of problems, the main being that the fuel consumption of the engines did not allow the aircraft to fly at high speeds long enough to evaluate the “thermal soaking” of the airframe, which was one of the main research areas it was built to investigate.

Combined with fuel leaks, the inability to reach its design speed of Mach 2 and a take-off speed at nearly 300 mph (480 km/h), the test phase was severely compromised.

Nonetheless, although the 188 program was eventually abandoned, the knowledge and technical information gained was put to some use for the future Concorde program.

The inconclusive nature of the research into the use of stainless steel led to Concorde’s being constructed from conventional aluminium alloys with a Mach limit of 2.2.

Experience gained with the Gyron Junior engine, which was the first British gas turbine designed for sustained supersonic operation, additionally later assisted with the development of the Bristol (later Rolls Royce) Olympus 593 powerplant which was used on both Concorde and the BAC TSR-2.

The announcement that all development was terminated was made in 1964, the last flight of XF926 taking place on 12 January 1964. In total the project cost £20 million.

By the end of the program, considered the most expensive to date for a research aircraft in Great Britain, each aircraft had to be “cannibalized” in order to keep the designated airframe ready for flight.





77 ft 8 in (23.67 m)


35 ft 1 in (10.69 m)


12 ft 0 in (3.66 m)

Wing area

396 sq ft (36.8 m2)


Biconvex 4%


2 × de Havilland DGJ.10R Gyron Junior afterburning turbojet engines,

10,000 lbf (44 kN) thrust each

14,000 lbf (62.28 kN) with afterburner at sea level

20,000 lbf (88.96 kN) with afterburner at 36,000 ft (10,973 m)


Maximum speed

1,043 kn (1,200 mph, 1,932 km/h) + (Design goal)

Maximum speed

Mach 2.


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