Bristol 188

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Bristol 188

Bristol 188 at the RAF Museum, Cosford.
Type	Experimental aircraft
Manufacturer	Bristol Aeroplane Company
Maiden flight	14 April 1962
Status	Experimental
Primary user	Royal Air Force
Number built	2

Bristol 188 at the RAF Museum, Cosford.

The Bristol 188 was a British supersonic research aircraft built by the Bristol Aeroplane Company. Its length, slender cross-section and intended purpose led to its being nicknamed the "Flaming Pencil."

The plane had its genesis in the OR.330 contract for a high-speed reconnaissance aircraft, which eventually developed into the Avro 730. As the 730 was expected to operate at high speeds for extended periods of time, more data was needed on high-speed operations, leading to Operational Requirement ER.134T for a testbed for attaining speeds greater than Mach 2. The aircraft was expected to run at these speeds for extended periods of time, allowing it to study kinetic heating effects on such an aircraft.

Several firms took interest in this very advanced specification and the eventual contract was awarded to Bristol, number 6/Acft/10144 in February 1953.

Bristol gave the aircraft the type number 188, of which three aircraft were to be built, one a pure test bed and the other two (constructors numbers 13518 and 13519) for flight testing. Under contract number KC/2M/04/CB.42(b) serial numbers XF923 and XF926 were given on 4 January 1954 to the two that would fly. To support the development of the Avro 730 Mach 2 reconnaissance bomber another three aircraft were ordered (Serial Numbers XK429, XK434 and XK436), the order was cancelled when the Avro 730 programme was cancelled in 1957 as part of the review of defence spending

The advanced nature of the aircraft meant that stainless steel was used for the construction of the outer skin with a honeycomb center, to which no paint was applied, but the problems with the new Argon arc welding technique known as puddle-welding caused long delays and was less than satisfactory. W. G. Armstrong Whitworth gave much technical help and support to Bristol.

Rolls-Royce engines were at first selected to power the 188, but five engine combinations were tried: two with Rolls Royce Avon 200s, two with the de Havilland Gyron Junior and one with an AJ.65, the latter disintegrating on test. But the final choice for the 188 were two 10,000 lbf (44 kN) thrust Gyron Junior DGJ10Rs developing 14,000 lbf (62 kN) of thrust on reheat at sea level and 20,000 lbf (89 kN) at Mach 2 at 36,000 ft (11 km).

Farnborough in May 1960 saw the first aircraft delivered for structural tests before moving on to RAE Bedford. XF923 undertook the first taxiing trials on 26 April 1961 but the first flight was not until 14 April 1962 following problems. XF926 had its first flight on 26 April 1963 managing to reach a speed of Mach 1.88 (2,300 km/h) at 36,000 feet (11 km).

The project suffered a number of problems; the main one being that the fuel consumption of the engines didn't 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. Also the take off speed was nearly 300 mph. Though it was eventually abandoned, the knowledge and technical information gained was put to some use for the future Concorde program. The inconclusivity of the research into the use of stainless steel led to Concorde being constructed from conventional aluminium alloys with a Mach limit of 2.2.

The project cost £20 million.

The fate of XF923 is unknown (probably scrapped) but XF926 is preserved at the RAF Museum, Cosford near Wolverhampton.

The Bristol 188 was sometimes called the "flaming pencil" (cf "flying pencil")