Question

What is gross thrust?

(a) Thrust produced at the exit of the nozzle

(b) The difference between the stream force entering and leaving the engine

(c) The stream force exited at the exit of the engine

(d) The product of stream force entering and leaving the engine

The question was posed to me during an interview for a job.

My question is taken from Thrust Producing Power Plant in division Aircraft Force Systems and the Equations of Motion of Aircraft Performance

Answer 1

The correct option is (a) Thrust produced at the exit of the nozzle

Easiest explanation: The gross thrust is the thrust produced at the exit of the nozzle. It is represented by FG. It is also equal to the rate of change of momentum at the exhaust gas flow. The equation is given as FG=ṁVj where FG is gross thrust, ṁ is mass flow rate and Vj is exit velocity.