Bristol 188
The Bristol 188 was a British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

Supersonic speed is a rate of travel of an object that exceeds the speed of sound . For objects traveling in dry air of a temperature of 20 °C this speed is approximately 343 m/s, 1,125 ft/s, 768 mph or 1,235 km/h. Speeds greater than five times the speed of sound are often...

 research aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

 built by the Bristol Aeroplane Company
Bristol Aeroplane Company
The Bristol Aeroplane Company, originally the British and Colonial Aeroplane Company, was both one of the first and one of the most important British aviation companies, designing and manufacturing both airframes and aero engines...

 in the 1950s. Its length, slender cross-section and intended purpose led to its being nicknamed the "Flaming Pencil".

Design and development

The aircraft had its genesis in Operational Requirement
Operational Requirement
An Operational Requirement or was a UK Air Ministry document setting out the required characteristics for a future military aircraft or weapon system....

 330 for a high speed (Mach 3) reconnaissance
Reconnaissance is the military term for exploring beyond the area occupied by friendly forces to gain information about enemy forces or features of the environment....

 aircraft, which eventually developed into the Avro 730
Avro 730
|-See also:-References:CitationsBibliography* Bartlett, Christopher John. "The Long Retreat: A Short History of British Defence Policy, 1945-70". Macmillan, 1971.* Brookes, Andrew J. "V-Force: The History of Britain's Airborne Deterrent ". Jane's, 1982....

. 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 capable of speeds greater than Mach 2
Mach number
Mach number is the speed of an object moving through air, or any other fluid substance, divided by the speed of sound as it is in that substance for its particular physical conditions, including those of temperature and pressure...

. The aircraft was expected to run at these speeds for extended periods of time, allowing it to study kinetic heating effects
Aerodynamic heating
Aerodynamic heating is the heating of a solid body produced by the passage of fluid over a body such as a meteor, missile, or airplane. It is a form of forced convection in that the flow field is created by forces beyond those associated with the thermal processes...

 on such an aircraft. The aircraft was expected to spend a considerable amount of time with a skin temperature around 300 Celsius.

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

Bristol gave the project the type number 188, of which three aircraft were to be built, one a pure test bed and the other two (constructor numbers 13518 and 13519) for flight testing. Under contract number KC/2M/04/CB.42(b) serial number
Serial number
A serial number is a unique number assigned for identification which varies from its successor or predecessor by a fixed discrete integer value...

s XF923 and XF926 were given on 4 January 1954 to the two that would fly. To support the development of the Avro 730
Avro 730
|-See also:-References:CitationsBibliography* Bartlett, Christopher John. "The Long Retreat: A Short History of British Defence Policy, 1945-70". Macmillan, 1971.* Brookes, Andrew J. "V-Force: The History of Britain's Airborne Deterrent ". Jane's, 1982....

 Mach 2 reconnaissance bomber, another three aircraft were ordered (Serial Numbers XK429, XK434 and XK436). The follow-up order was cancelled when the Avro 730 programme was cancelled in 1957 as part of that year's review of defence spending
1957 Defence White Paper
The 1957 White Paper on Defence was a British white paper setting forth the perceived future of the British military. It had profound effects on all aspects of the defence industry but probably the most affected was the British aircraft industry...

. The 188 project was continued as a high speed research aircraft.
The advanced nature of the aircraft meant that new construction methods had to be developed. Several materials were considered for construction and two specialist grades of steel were selected: a titanium
Titanium is a chemical element with the symbol Ti and atomic number 22. It has a low density and is a strong, lustrous, corrosion-resistant transition metal with a silver color....

-stabilized 18-8 austenitic steel and a 12%-Cr
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...

 steel used in gas turbines (Firth-Vickers
Firth Brown Steels
Firth Brown Steels was initially formed in 1902, when Sheffield steelmakers John Brown and Company exchanged shares and came to a working agreement with neighbouring company Thomas Firth & Sons...

 Rex 448). These had to be manufactured to better tolerances in sufficient quantities for construction to start. The 12% chromium
Chromium is a chemical element which has the symbol Cr and atomic number 24. It is the first element in Group 6. It is a steely-gray, lustrous, hard metal that takes a high polish and has a high melting point. It is also odorless, tasteless, and malleable...

 stainless steel
Stainless steel
In metallurgy, stainless steel, also known as inox steel or inox from French "inoxydable", is defined as a steel alloy with a minimum of 10.5 or 11% chromium content by mass....

 with a honeycomb
Honeycomb (geometry)
In geometry, a honeycomb is a space filling or close packing of polyhedral or higher-dimensional cells, so that there are no gaps. It is an example of the more general mathematical tiling or tessellation in any number of dimensions....

 centre was used for the construction of the outer skin, to which no paint was applied. Riveting was a potential method for construction but the new arc welding
Arc welding
Arc welding is a type of welding that uses a welding power supply to create an electric arc between an electrode and the base material to melt the metals at the welding point. They can use either direct or alternating current, and consumable or non-consumable electrodes...

 technique using an Argon
Argon is a chemical element represented by the symbol Ar. Argon has atomic number 18 and is the third element in group 18 of the periodic table . Argon is the third most common gas in the Earth's atmosphere, at 0.93%, making it more common than carbon dioxide...

 gas shield known as puddle welding
Welding is a fabrication or sculptural process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material that cools to become a strong joint, with pressure sometimes...

 was used. There were long delays with the method and was less than satisfactory. The W. G. Armstrong Whitworth
Armstrong Whitworth
Sir W G Armstrong Whitworth & Co Ltd was a major British manufacturing company of the early years of the 20th century. Headquartered in Elswick, Newcastle upon Tyne, Armstrong Whitworth engaged in the construction of armaments, ships, locomotives, automobiles, and aircraft.-History:In 1847,...

 company, provided substantial technical help and support to Bristol during this period; they produced major sections of the airframe as a subcontractor.

A fused-quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...

The windshield or windscreen of an aircraft, car, bus, motorbike or tram is the front window. Modern windshields are generally made of laminated safety glass, a type of treated glass, which consists of two curved sheets of glass with a plastic layer laminated between them for safety, and are glued...

 and canopy and cockpit
A cockpit or flight deck is the area, usually near the front of an aircraft, from which a pilot controls the aircraft. Most modern cockpits are enclosed, except on some small aircraft, and cockpits on large airliners are also physically separated from the cabin...

 refrigeration system were designed and fitted but were never tested in the environment for which they had been designed.

The engine installations had to allow development of variable-geometry intake systems. These would permit maximum efficiency across a range of supersonic speeds. This had also led to the engines' position on the wings rather than within the fuselage. Rolls-Royce
Rolls-Royce Limited
Rolls-Royce Limited was a renowned British car and, from 1914 on, aero-engine manufacturing company founded by Charles Stewart Rolls and Henry Royce on 15 March 1906 as the result of a partnership formed in 1904....

 engines were initially selected to power the 188, but five engine combinations were subsequently evaluated: two with Rolls-Royce Avon
Rolls-Royce Avon
|-See also:-Bibliography:* Gunston, Bill. World Encyclopaedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9-External links:**** a 1955 Flight article on the development of the Avon...

 200s, two with the de Havilland Gyron Junior
De Havilland Gyron Junior
|-See also:-External links:* *...

 and one with an AJ.65
Rolls-Royce Avon
|-See also:-Bibliography:* Gunston, Bill. World Encyclopaedia of Aero Engines. Cambridge, England. Patrick Stephens Limited, 1989. ISBN 1-85260-163-9-External links:**** a 1955 Flight article on the development of the Avon...

, the last disintegrating on test. Finally, in 1957, the choice for the 188 was two 10,000 lbf (44 kN) thrust
Thrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....

 Gyron Junior DGJ10Rs, developing 14,000 lbf (62 kN) of thrust on reheat
The AfterBurner is a lighting solution for the Game Boy Advance system that was created by Triton-Labs.Originally, was a website created to petition Nintendo to put some kind of light in their Game Boy Advance system...

 at sea level and 20,000 lbf (89 kN) at Mach 2 at 36,000 ft (11,000 m).

The Gyron Junior was then under development for the Saunders-Roe SR.177 supersonic interceptor and incorporated a fully variable reheat, from idle to full power, the first such application used in an aircraft. Unfortunately this choice of powerplant resulted in the 188 having a typical endurance of only 25 minutes, which was too little time for any serious high-speed research. Chief Test Pilot Godfrey L. Auty reported that while the 188 transitioned smoothly from subsonic to supersonic flight, the Gyron Junior engines were prone to surging beyond that speed, causing the aircraft to pitch
Flight dynamics
Flight dynamics is the science of air vehicle orientation and control in three dimensions. The three critical flight dynamics parameters are the angles of rotation in three dimensions about the vehicle's center of mass, known as pitch, roll and yaw .Aerospace engineers develop control systems for...

 and yaw.

In order to solve the aerodynamic and flutter problems, a large number of scale models were employed. Mounted on converted rocket boosters, a number of models were launched from RAE Aberporth, for free-flight investigation.

Operational history

In May 1960, the first airframe was delivered to the Royal Aircraft Establishment
Royal Aircraft Establishment
The Royal Aircraft Establishment , was a British research establishment, known by several different names during its history, that eventually came under the aegis of the UK Ministry of Defence , before finally losing its identity in mergers with other institutions.The first site was at Farnborough...

 at Farnborough for structural tests – loading tests both heated and unheated – before moving on to RAE Bedford
RAE Bedford
RAE Bedford based near the village of Thurleigh, north of the town of Bedford in England, has been the site of major aircraft experimental development work....

. XF923 undertook the first taxiing
Taxiing refers to the movement of an aircraft on the ground, under its own power, in contrast to towing or push-back where the aircraft is moved by a tug...

 trials on 26 April 1961, although due to problems encountered, 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 programme. Over 51 flights, it managed a top speed of Mach 1.88 (1,440 mph : 2,300 km/h) at 36,000 ft (11,000 m). The longest subsonic Bristol 188 flight was only 48 minutes in length, requiring 70% of the fuel load to be expended to attain its operational altitude.
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 takeoff
Takeoff is the phase of flight in which an aerospace vehicle goes from the ground to flying in the air.For horizontal takeoff aircraft this usually involves starting with a transition from moving along the ground on a runway. For balloons, helicopters and some specialized fixed-wing aircraft , no...

 speed at nearly 300 mph (482.8 km/h), the test phase was severely compromised. Nonetheless, although the 188 programme was eventually abandoned, the knowledge and technical information gained was put to some use for the future Concorde
Aérospatiale-BAC Concorde was a turbojet-powered supersonic passenger airliner, a supersonic transport . It was a product of an Anglo-French government treaty, combining the manufacturing efforts of Aérospatiale and the British Aircraft Corporation...

 program. The inconclusive nature of the research into the use of stainless steel led to Concorde's being constructed from conventional aluminium
Aluminium or aluminum is a silvery white member of the boron group of chemical elements. It has the symbol Al, and its atomic number is 13. It is not soluble in water under normal circumstances....

 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
Rolls-Royce Olympus
The Rolls-Royce Olympus was one of the world's first two-spool axial-flow turbojet aircraft engines, originally developed and produced by Bristol Aero Engines. First running in 1950, its initial use was as the powerplant of the Avro Vulcan V Bomber...

 powerplant which was used on both Concorde and the BAC TSR-2
The British Aircraft Corporation TSR-2 was a cancelled Cold War strike and reconnaissance aircraft developed by the British Aircraft Corporation for the Royal Air Force in the late 1950s and early 1960s...


Various proposals to further develop the 188 were considered including incorporating ramjet
A ramjet, sometimes referred to as a stovepipe jet, or an athodyd, is a form of airbreathing jet engine using the engine's forward motion to compress incoming air, without a rotary compressor. Ramjets cannot produce thrust at zero airspeed and thus cannot move an aircraft from a standstill...

s and rocket engine
Rocket engine
A rocket engine, or simply "rocket", is a jet engineRocket Propulsion Elements; 7th edition- chapter 1 that uses only propellant mass for forming its high speed propulsive jet. Rocket engines are reaction engines and obtain thrust in accordance with Newton's third law...

s as well as considering fighter
Fighter aircraft
A fighter aircraft is a military aircraft designed primarily for air-to-air combat with other aircraft, as opposed to a bomber, which is designed primarily to attack ground targets...

 and reconnaissance variants. One serious proposal involved the fitting of "wedge" type intakes.

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 programme, considered the most expensive to date for a research aircraft in Great Britain, each aircraft had to be "cannibalised" in order to keep the designated airframe ready for flight.


In April 1966, both 188 fuselages were transported to the Proof and Experimental Establishment at Shoeburyness
Shoeburyness is a town in southeast Essex, England, situated at the mouth of the river Thames Estuary. It is within the borough of Southend-on-Sea, and is situated at the far east of the borough, around east of Southend town centre...

, Essex to act as targets for gunnery trials, but during 1972, XF926 was dismantled and moved to RAF Cosford (without its engines) to act as instructional airframe 8368M, and is preserved at the Royal Air Force Museum Cosford
Royal Air Force Museum Cosford
The Royal Air Force Museum Cosford is a museum dedicated to the history of aviation, and the Royal Air Force in particular. The museum is a non-departmental public body sponsored by the Department for Culture, Media and Sport and a registered charity...

 near Wolverhampton
Wolverhampton is a city and metropolitan borough in the West Midlands, England. For Eurostat purposes Walsall and Wolverhampton is a NUTS 3 region and is one of five boroughs or unitary districts that comprise the "West Midlands" NUTS 2 region...

. XF923 was subsequently scrapped at Foulness
Foulness is an island on the east coast of Essex in England, which is separated from the mainland by narrow creeks. The large island had a usually resident population of 212 people in the 2001 census, who live in the settlements of Churchend and Courtsend, at the north end of Foulness. The island...


Notable appearances in media

The Bristol 188 (XF923) was prominently featured in Some People
Some People
Some People is a 1962 film directed by Clive Donner. It stars Kenneth More and Ray Brooks.-Cast:* Kenneth More as Mr. Smith* Ray Brooks as Johnnie* Anneke Wills as Anne* David Andrews as Bill* Angela Douglas as Terry* David Hemmings as Bert...

1962 in film
The year 1962 in film involved some significant events.-Events:*May - The Golden Horse Film Festival and Awards are officially founded by the Taiwanese government....

, a feature film primarily shot in Bristol.

Specifications (Bristol 188)

External links

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