In an aircraft with mixed propulsion (also referred to as a hybrid aircraft ), the propulsion of the aircraft is achieved by a combination of different engines ( hybrid propulsion ). Such aircraft were used from the 1940s to give military aircraft a special performance in certain situations.
Jet engine and rocket engine
A rocket engine was used when particularly high demands were placed on climbing performance.
With the increase in efficiency and performance of jet engines, in particular through the introduction of turbofans with afterburner , these combinations were no longer required from around the mid-1950s.
Remarkably, this combination is used in the high-speed land vehicle Bloodhound SSC (as of 2017).
Rocket propulsion and nuclear propulsion
A nuclear-powered ramjet, which should have been brought up to the necessary speed by rocket propulsion, was developed for the Pluto project.
Turbine jet engine and ramjet engine
This combination is still relevant when it comes to reaching the highest speeds. This is because the turbine jet engine reaches physical limits at high speeds, while the ramjet engine only begins to function at high speeds. An older example of this combination is the Nord 1500 Griffon. The Pratt & Whitney J58 of the SR-71 also combines both types of engines in one engine, depending on the speed.
An example of a current development project that includes such a hybrid drive is the ESA's Long-Term Advanced Propulsion Concepts and Technologies (LAPCAT) project .
Rocket engine and ramjet engine
The Boeing X-51 project, carried out from 2010 to 2013, was supposed to achieve a speed of Mach 6+ by using a rocket engine to accelerate it to around Mach 4.8 in the initial phase and then igniting a ramjet.
- Willy JG Bräunling: aircraft engines. 4th edition, Springer Vieweg Verlag, Heidelberg 2015, ISBN 978-3-642-34538-8 .
- Aviation Paperback . JF Lehmann publisher, 1957.