Tupolev Design Bureau has solved the problem of heating the airframe during flight at hypersonic speeds

© Russian Aviation / Tu-144 supersonic jet, MAKS-2017 / Archive photo

Tupolev PJSC patented hypersonic airplane with a combined propulsion system, including two turbojet engines working on jet fuel and another – on cryogenic fuel. This is reported by TASS with reference to the description of the invention to the patent.

The invention is designed to solve the problem of airframe heating during flight at supersonic and hypersonic speeds, caused by the interaction of external surfaces with the oncoming air flow.

“When operating a turbojet using cryogenic fuel, the airplane is accelerated to hypersonic speed. At the same time, due to increased friction of the external parts of the airframe on the air is their intense heating and to continue a long flight at hypersonic speed, it is necessary to cool them. For this purpose, cryogenic fuel flows from the tank through pipelines to the most heated parts of the airframe and engine, as a result of which there is an intensive gasification of cryogenic fuel in the pipelines. This process is endothermic in nature, in which heat is absorbed from the heated parts of the airframe and engine. The heated cryogenic fuel turns into a gaseous form and is fed into the combustion chamber of the engine and afterburner to create thrust,” the description explains.

The hypersonic airplane may use T-6 or T-8B thermostable fuel as aviation kerosene, and liquefied natural gas or liquefied hydrogen as cryogenic fuel.

Among the authors of the invention is Valery Benderov, Honored Designer of Russia, who in 2012-2019 held the position of Program Director – Chief Designer of the Multifunctional Flight Modeling Complex (LMK-214), a leading design engineer at the Tupolev Design Bureau.