The Bristol 188 is a British
supersonic research aircraft built by the
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 aircraft engines. Notable a ...
in the 1950s. Its length, slender cross-section and intended purpose led to its being nicknamed the "Flaming Pencil".
["Bristol Aircraft."](_blank)
''Gloucestershire Transport History''. Retrieved: 5 January 2008.
Design and development
The aircraft had its genesis in
Operational Requirement
An Operational Requirement, commonly abbreviated OR, was a United Kingdom (UK) Air Ministry document setting out the required characteristics for a future (i.e., as-yet unbuilt) military aircraft or weapon system.
The numbered OR would describe ...
330 for a high speed (
Mach 3)
reconnaissance aircraft
A reconnaissance aircraft (colloquially, a spy plane) is a military aircraft designed or adapted to perform aerial reconnaissance with roles including collection of imagery intelligence (including using photography), signals intelligence, as ...
, which eventually developed into the
Avro 730
The Avro 730 was a planned Mach 3 reconnaissance aircraft and strategic bomber that was being developed by Avro Aircraft for the Royal Air Force (RAF). It had been originally envisioned as a very high-speed aircraft to perform aerial reconna ...
. 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
A testbed (also spelled test bed) is a platform for conducting rigorous, transparent, and replicable testing of scientific theories, computational tools, and new technologies.
The term is used across many disciplines to describe experimental rese ...
capable of 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. The aircraft was expected to spend a considerable amount of time with a
skin
Skin is the layer of usually soft, flexible outer tissue covering the body of a vertebrate animal, with three main functions: protection, regulation, and sensation.
Other cuticle, animal coverings, such as the arthropod exoskeleton, have diffe ...
temperature around 300 Celsius.
Several firms took interest in this very advanced
specification
A specification often refers to a set of documented requirements to be satisfied by a material, design, product, or service. A specification is often a type of technical standard.
There are different types of technical or engineering specificati ...
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
A serial number is a unique identifier assigned incrementally or sequentially to an item, to ''uniquely'' identify it.
Serial numbers need not be strictly numerical. They may contain letters and other typographical symbols, or may consist enti ...
s ''XF923'' and ''XF926'' were given on 4 January 1954 to the two that would fly. To support the development of the
Avro 730
The Avro 730 was a planned Mach 3 reconnaissance aircraft and strategic bomber that was being developed by Avro Aircraft for the Royal Air Force (RAF). It had been originally envisioned as a very high-speed aircraft to perform aerial reconna ...
Mach 3 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. The 188 project was continued as a high speed research aircraft.
![Bristol Type 188 (XF926) Front](https://upload.wikimedia.org/wikipedia/commons/6/61/Bristol_Type_188_%28XF926%29_Front.jpg)
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. Found in nature only as an oxide, it can be reduced to produce a lustrous transition metal with a silver color, low density, and high strength, resistant to corrosion in ...
-stabilized 18-8
austenitic steel and a 12%-
Cr steel used in gas turbines (
Firth-Vickers ''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 with the symbol Cr and atomic number 24. It is the first element in group 6. It is a steely-grey, lustrous, hard, and brittle transition metal.
Chromium metal is valued for its high corrosion resistance and hardne ...
stainless steel
Stainless steel is an alloy of iron that is resistant to rusting and corrosion. It contains at least 11% chromium and may contain elements such as carbon, other nonmetals and metals to obtain other desired properties. Stainless steel's corros ...
with a
honeycomb
A honeycomb is a mass of Triangular prismatic honeycomb#Hexagonal prismatic honeycomb, hexagonal prismatic Beeswax, wax cells built by honey bees in their beehive, nests to contain their larvae and stores of honey and pollen.
beekeeping, Beekee ...
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 is a welding process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals, when cool, result in a binding of the metals. It is a type of welding that uses a welding powe ...
technique using an
argon
Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as abu ...
gas shield known as
puddle welding was used. There were long delays with the method, which was less than satisfactory. The
W. G. Armstrong Whitworth company provided substantial technical help and support to Bristol during this period; they produced major sections of the airframe as a subcontractor. North American used the same methods of argon welding of stainless steel honeycomb sheet metal for the
XB-70 Valkyrie
The North American Aviation XB-70 Valkyrie was the prototype version of the planned B-70 nuclear-armed, deep-penetration supersonic strategic bomber for the United States Air Force Strategic Air Command. Designed in the late 1950s by North Ame ...
bomber.
A fused-
quartz
Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical form ...
windscreen
The windshield (North American English) or windscreen (Commonwealth English) of an aircraft, car, bus, motorbike, truck, train, boat or streetcar is the front window, which provides visibility while protecting occupants from the elements. Mo ...
and
canopy
Canopy may refer to:
Plants
* Canopy (biology), aboveground portion of plant community or crop (including forests)
* Canopy (grape), aboveground portion of grapes
Religion and ceremonies
* Baldachin or canopy of state, typically placed over an a ...
and
cockpit
A cockpit or flight deck is the area, usually near the front of an aircraft or spacecraft, from which a Pilot in command, pilot controls the aircraft.
The cockpit of an aircraft contains flight instruments on an instrument panel, and the ...
refrigeration system were designed and fitted but were never tested in the environment for which they had been designed.
The specification for the aircraft required engine installations which permitted the fitting of different air intakes, engines and propelling nozzles. The 188 was originally intended to have
Avon engines but the half ton lighter each
Gyron Junior was substituted in June 1957, necessitating the engines mounted further forward with longer nacelles and jet pipes.
The Gyron Junior was then under development for the
Saunders-Roe SR.177
The Saunders-Roe SR.177 was a 1950s project to develop a combined jet- and rocket-powered interceptor aircraft for the Royal Air Force (RAF) and Royal Navy. It was an enlarged derivative of the Saunders-Roe SR.53, which was itself an experi ...
supersonic interceptor and incorporated a fully variable reheat, which achieved a smooth variation in thrust between dry and full reheat, so being one of the first in the world to give continuous variation in thrust from idle to max reheat. This choice of powerplant resulted in the 188 having a typical endurance of only 25 minutes, not long enough for the high-speed research tests that were required. 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 and
yaw.
In order to solve the aerodynamic and flutter problems, a large number of scale models were tested. Some, mounted on converted rocket boosters, were launched from RAE Aberporth, for free-flight investigation.
[King 1962, p. 695.]
Operational history
![Bristol 188 XF923 FAR 08](https://upload.wikimedia.org/wikipedia/commons/c/c6/Bristol_188_XF923_FAR_08.09.62_edited-3.jpg)
In May 1960, the first airframe was delivered to the
Royal Aircraft Establishment
The Royal Aircraft Establishment (RAE) was a British research establishment, known by several different names during its history, that eventually came under the aegis of the Ministry of Defence (United Kingdom), UK Ministry of Defence (MoD), bef ...
at Farnborough for structural tests, both heated and unheated, before moving on to
RAE Bedford
RAE Bedford was a research site of the Royal Aircraft Establishment between 1946 and 1994. It was located near the village of Thurleigh, north of the town of Bedford in England and was the site of aircraft experimental development work.
In the ...
. ''XF923'' undertook the first
taxiing
Taxiing (rarely spelled taxying) is the movement of an aircraft on the ground, under its own power, in contrast to towing or pushback where the aircraft is moved by a tug. The aircraft usually moves on wheels, but the term also includes aircra ...
trials on 26 April 1961, although due to problems, the first flight was not until 14 April 1962.
["World News: T.188 Discontinued."](_blank)
''Flight International'', 20 February 1964, p. 267. ''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 ''XF923''s engines, on 26 April 1963. ''XF926'' was given over to RAE Bedford for its flying programme.
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).
["Individual Aircraft History: Accession number 83/A/1112."](_blank)
''RAF Museum''. Retrieved: 22 June 2010. 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
The Farnborough Airshow, officially the Farnborough International Airshow, is a trade exhibition for the aerospace and defence industries, where civilian and military aircraft are demonstrated to potential customers and investors. Since its fir ...
. 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.
[King 1962, p. 702.] The flight information transmitted meant that a "ground pilot" could advise the pilot.
![Bristol Type 188 (XF926) tail](https://upload.wikimedia.org/wikipedia/commons/c/c5/Bristol_Type_188_%28XF926%29_tail.jpg)
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 leaves the ground and becomes airborne. For aircraft traveling vertically, this is known as liftoff.
For aircraft that take off horizontally, this usually involves starting with a t ...
speed at nearly , 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
The Aérospatiale/BAC Concorde () is a retired Franco-British supersonic airliner jointly developed and manufactured by Sud Aviation (later Aérospatiale) and the British Aircraft Corporation (BAC).
Studies started in 1954, and France an ...
program. The inconclusive nature of the research into the use of stainless steel led to Concordes being constructed from conventional
aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. I ...
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 British Aircraft Corporation TSR-2 is a cancelled Cold War strike and reconnaissance aircraft developed by the British Aircraft Corporation (BAC), for the Royal Air Force (RAF) in the late 1950s and early 1960s. The TSR-2 was designed ...
.
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.
[Winchester 2005, p. 198.] By the end of the programme, considered the most expensive to date for a research aircraft in Great Britain, one aircraft had to be "cannibalised" in order to keep the other airframe flightworthy.
Surviving aircraft
In April 1966, both 188 fuselages were transported to the
Proof and Experimental Establishment
The Proof and Experimental Establishment (PXE) is an Indian defence laboratory of the Defence Research and Development Organisation (DRDO). Located in Balasore, Orissa, India. its main purpose concerns the research and development of technolog ...
at
Shoeburyness
Shoeburyness (; also called Shoebury) is a suburb of the city of Southend-on-Sea, in the City of Southend-on-Sea, in the ceremonial county of Essex, England. east of the city centre. It was an urban district of Essex from 1894 to 1933, when it ...
, Essex to act as targets for gunnery trials, but during 1972, ''XF926'' was dismantled and moved to
RAF Cosford
Royal Air Force Cosford or RAF Cosford (formerly DCAE Cosford) is a Royal Air Force station in Cosford, Shropshire, Cosford, Shropshire, just to the northwest of Wolverhampton and next to Albrighton, Bridgnorth, Albrighton.
History
Origins
RA ...
(without its engines) to act as instructional airframe 8368M, and is preserved at the
Royal Air Force Museum Cosford
The Royal Air Force Museum Cosford, located in Cosford in Shropshire, is a free (currently, 2022) museum dedicated to the history of aviation and the Royal Air Force in particular. The museum is part of the Royal Air Force Museum, a non-departme ...
in
Shropshire
Shropshire (; alternatively Salop; abbreviated in print only as Shrops; demonym Salopian ) is a landlocked historic county in the West Midlands region of England. It is bordered by Wales to the west and the English counties of Cheshire to th ...
.
''XF923'' was subsequently scrapped at
Foulness
Foulness Island () is a closed island on the east coast of Essex in England, which is separated from the mainland by narrow creeks. In the 2001 census, the usually resident population of the civil parish was 212, living in the settlements of Ch ...
.
Operators
;
*
Royal Aircraft Establishment
The Royal Aircraft Establishment (RAE) was a British research establishment, known by several different names during its history, that eventually came under the aegis of the Ministry of Defence (United Kingdom), UK Ministry of Defence (MoD), bef ...
Specifications (Bristol 188)
Notable appearances in media
Bristol 188 ''XF923'' was prominently featured in ''
Some People (1962)'', a feature film primarily shot in Bristol.
See also
References
Citations
Bibliography
* Butler, Phil. "The Bristol 188". ''Air-Britain Aeromilitaria'', Spring 2004, Vol. 30, Issue 116. pp. 11–14.
*Buttler, Tony and Jean-Louis Delezenne. ''X-Planes of Europe: Secret Research Aircraft from the Golden Age 1946-1974''. Manchester, UK: Hikoki Publications, 2012.
* King, H. F., Technical Editor
"Bristol 188: A Versatile Research Aeroplane."''Archive: Flight International'', 3 May 1962, pp. 695–703, 705. via ''flightglobal.com''.
* Winchester, Jim. ''The World's Worst Aircraft: From Pioneering Failures to Multimillion Dollar Disasters''. London: Amber Books Ltd., 2005. .
External links
Royal Air Force Museum Bristol Type 188
{{British military aircraft since World War II
1960s British experimental aircraft
188
Aircraft first flown in 1962