Question

What is specific endurance?

(a) It is instantaneous flight distance per unit of time

(b) It is instantaneous flight time per unit of distance

(c) It is instantaneous flight distance per unit of fuel consumed

(d) It is instantaneous flight time per unit of fuel consumed

This question was posed to me in exam.

I need to ask this question from Cruising Performance in chapter Cruising Performance of Aircraft Performance

Answer 1

Correct option is (d) It is instantaneous flight time per unit of fuel consumed

For explanation I would say: Specific endurance (SE) is the instantaneous flight time per unit of fuel consumed. Specific endurance (SE) can be expressed as SE=\(\frac{1}{Q_f}\) where Qf is fuel mass flow. The units of SAR are time/mass i.e. hr/Kg.