To ensure normal operation of the fuel system of an aircraft or helicopter during different flight modes under conditions of high altitude and to reduce its weight and increase the reliability, the fuel is generally supplied from the feeder tank into the engine by two pumping stages.
Electric centrifugal pump units (ECP) comprising a monoblock configuration of a pump and electric motor, are widely used in fuel and other hydraulic systems of aircraft. Several dozens of ECP are mounted on some airplanes just to pump fuel
The large amount of R&D works conducted by Kristall Design Bureau aimed at the development of new structural schemes of units to achieve stable frequency of AC electric generators resulted in the idea to use hydrodynamic transmission that uses fuel as a working medium, which also serves for cooling the generator at the same time.
For some types of small-sized aircraft engines, the rotor speed of which makes 50,000-60,000 rpm, the necessity to develop a high-speed displacement fuel pump, which is driven directly from the engine rotor, became apparent.
Kristall Design Bureau developed a number of turbopump assemblies for emergency hydraulic systems – TNUA, TNU-86-3, TNU-86A and TNUK, which provide power and ensure flight completion in emergency situations caused by failure of main power supply sources of hydraulic systems.
To ensure operation of aircraft hydraulic systems in emergency situations related to the failure of main hydraulic pumps, Kristall Design Bureau developed the line-up of emergency ram air turbines (RAT).