The British ER134 D specification, the fastest in the world at the time, was completed in 1954 in response to the US X 15 space plane project. The aircraft had to dissipate severe heat, which required innovative engineering in order to maintain speeds of Mach 2.75 for lengthy periods of time. A contract was given to Bristol Aeroplane to build six Bristol type 188 airframes, an experimental twin-engine jet plane made of stainless steel that was intended to minimize kinetic heating, which would have melted conventional aircraft. The Flying pencil got its nickname from its thin, costly, and intricate design.
Following the English Electric Lightning’s 1954 first flight, supersonic flight became the norm for military aircraft in the 1950s. As a result, the UK was able to reach speeds twice the speed of sound. Supersonic aircraft, however, posed difficulties for engineers, pilots, and designers. In an effort to gain air superiority, the Royal Air Force developed specification ER 134 D, which allowed for steam flight at Mach 2.75 and higher. The objective was to get knowledge about kinetic heating and keep the aircraft safe for pilots while achieving top speed. After the US X-15 spacecraft, the British eventually possessed the second-fastest aircraft in the world.
With the goal of gathering information on the kinetic heating effects of an aircraft operating at Mach three or higher, the type 188 was created to satisfy ER 134 D requirements for a high-speed reconnaissance aircraft. With a skin temperature of around 300 degrees Celsius, the project’s goal was to present definitive data on high-speed operations and the kinetic heating effects of an aircraft. In February 1953, Bristol Aircraft was given the go-ahead for project 188. Three aircraft were to be built by the company: two for flight testing and one as a testbed. XF 923 and XF 926 were the designations given to the aircraft. It was determined, after considerable deliberation, that new building techniques would be necessary for the development of the advanced aircraft.
For their aircraft, Bristol chose unique steel grades such as mixed steel with chromium content and austenitic titanium steel. But the project ran into problems, such applying chromium mixed steel via puddle welding, which slowed down progress and produced inadequate results. The WG Armstrong Whitworth Company provided critical technical support for the production of certain airplane components. A fused quartz cooling system was designed but never tested to maintain a steady cockpit. The process was delayed because the aircraft required engine installations that could accept various engine types, air intakes, and propelling nozzles. The type 188’s endurance was just 25 minutes, significantly less than the necessary high-speed research experiments, due to the usage of lighter Gyron Jr. engines instead of the heavier Avon engines that were originally planned.
The first completed aircraft, handed to the Royal Air Force in 1960 for static testing, was the XF 923. Nevertheless, it required a year of effort due to afterburner and input difficulties. Several large-scale models were created and tested to address problems, some of which were mounted on rocket boosters to evaluate the models’ ability to fly freely. Eight years after the initial procurement, in 1962, the plane was prepared for takeoff. On a transfer flight from Bristol to Boscombedown, the 188 made its first flight. Obtaining the proper materials and altering the middle wings owing to aerodynamic concerns were among the building obstacles encountered by the project.
Although the English Electric Lightning and Type 188 aircraft were prepared for flight in 1962, they had difficulty attaining Mach 2 speeds, even though their maximum shutter speed at 36,000 feet was Mach 1.88. There were only two minutes of high-speed flying due to the engines’ pitching and yawing, which quickly depleted fuel. The Royal Air Force’s interest in type 188 declined in the 1960s due to a shift in priorities away from missiles and high-speed aircraft. This resulted in the need to remodel engine bays, build new intakes, and replace the engines.
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