The Rolls-Royce RB.145 was a British jet engine designed in the early-1960s by Rolls-Royce for use as a lightweight VTOL lift and cruise engine. Developed from the Rolls-Royce RB108 the RB.145 featured more accessories and a higher thrust rating. Six engines developed by MAN Turbo were fitted to the first prototype of the EWR VJ 101 experimental German fighter aircraft, achieving supersonic flight by July 1964.
The thermal efficiency is expressed mathematically as:
where:
- is the thermal efficiency,
- is the thrust produced by the engine,
- is the jet velocity,
- ṁf is the mass flow rate of fuel,
- is the specific enthalpy of the fuel.