Question

What do you mean by scale factor in terms of rubber engine?

(a) ratio of thrust required by rubber engine to the actual thrust from selected existing engine

(b) Lift to drag ratio

(c) Thrust coefficient to drag coefficient

(d) Thrust required to thrust available

I had been asked this question in an internship interview.

This intriguing question originated from Propulsion topic in division Propulsion and Fuel System Integration of Aircraft Design

Answer 1

Right option is (a) ratio of thrust required by rubber engine to the actual thrust from selected existing engine

Explanation: For a typical rubber engine, scale factor is defined as ratio of thrust required by rubber engine to the actual thrust from selected existing engine. Scale factor can vary based on our requirements. Lift to drag ratio is primarily concern of aerodynamics of aircraft.