RID – Italian Defense Magazine

At Farnborough, the UK showcased the progress of its hypersonic research and presented the alliance between Rolls Royce, Reaction Engines and the Royal Air Force’s Rapid Capabilities Office (RCO). A scale model, called Concept V, of a reusable hypersonic aircraft to be built in the next few years as part of the Hypersonic Air Vehicle Experimental (HVX) project was presented at the air show.

The concept isn’t final yet, and, as the name suggests, it’s just one of a few designs the team is working on. If made in the form shown, it would result in an aircraft approximately 9m long with a 4m wingspan. The heart of the demonstrator is the propulsion system, made possible by the innovative precooler developed by Reaction Engines to cool the incoming air at supersonic speeds in the engine. Reaction Engines has been working on the precooler, and on the SABER engine that accompanies it, for many years with the aim of making it possible to develop space-planes capable of penetrating into space with a single transition stage from an air breathing motor to a rocket for exoatmospheric propulsion. Starting from 2019, however, thanks to an initial allocation of 10 million pounds from the RAF’s RCO, the Reaction Engines precooler has also been studied in terms of hypersonic flight and the improvement of performance and operational life of aircraft already existing. The first activities focused on the benefits that the cooling of the incoming air can generate for a jet engine today, specifically the EJ200 of the Eurofighter TYPHOON. The HVX, continuing the development on these lines, should lead to a jet engine that, thanks to the precooler and the cooling of the incoming air, allows the aircraft to go from zero speed to a high Mach number, higher than 4 At that point, the turbine would be sealed and the propulsive force would come from a Ramjet type engine, which needs, in order to function, an inlet air already at a high Mach number.

The Reaction Engines precooler, associated with an as yet unidentified jet engine, is already undergoing a ground test campaign that will progressively become more realistic until demonstrating, initially on the ground and perhaps in flight in 2023, the operation of the entire system. . The precooler has already been individually demonstrated in recent years thanks to the support of funds not only from the British government but also from ESA, NASA and USAF. At the end of 2019 the Precooler demonstrated its capabilities at Mach 5 by cooling the incoming air from 1000 ° to 100 ° in a twentieth of a second.

The tests, carried out in the United States at the TF2 laboratory of the Colorado Air and Space Port, involved the use of a General Electric J79 turbojet to generate the airflow at high speed and temperature. The cooling of the incoming air allows the engine positioned downstream of the heat exchanger to operate, regardless of real altitude and speed, as if it were at sea level and in the best possible conditions, so as to maximize the thrust generated. This, in theory, can be exploited in many ways, allowing precisely innovative propulsive formulas for flight to space, or for maintaining very high speeds in the atmosphere, or to dramatically reduce wear and pollution.

HVX is part of renewed UK efforts in the hypersonic sector. Through the AUKUS agreements, the country was also able to access the know-how of the Austro-American SciFire (Southern Cross Integrated Flight Research Experiment) project. The Defense Science and Technology Laboratory has projects underway to demonstrate aerodynamic technologies and formulas for a High Speed ​​Weapon and the Chief of Defense Staff has publicly reiterated to the Parliament’s Defense Commission that it considers it a priority to acquire hypersonic and counter-hypersonic capabilities in the next years.

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