Specialists from the Zhukovsky and Gagarin Air Force Academy in Voronezh have patented a device for turbojet bypass engines, according to the Rospatent database. It partially separates air and gas flows at the inlet to the mixing chamber, which reduces the aircraft's visibility to detection systems.
The device consists of four movable flaps that automatically move using hydraulic mechanisms. They change the thickness of the cold air stream. This stream shields the nozzle walls and the hot gas stream itself at the engine outlet. As a result, thermal radiation (i.e., infrared signature) and noise are simultaneously reduced.
The development is intended for military aviation: it makes the aircraft less vulnerable to missiles with thermal homing heads and acoustic reconnaissance equipment. The result is achieved through precise calculation of the size of the flaps: their length, width, depth of immersion in the flow, as well as the distance at which air and gas mix after the device.
