Question

What is specific fuel consumption?

(a) It is the fuel flow rate per unit distance

(b) It is the fuel flow rate per unit thrust

(c) It is the fuel flow rate per unit time

(d) It is the mass flow rate per unit thrust

This question was addressed to me in class test.

The question is from Range and Endurance for Aircraft with Thrust Producing Engines in portion Cruising Performance of Aircraft Performance

Answer 1

Right choice is (b) It is the fuel flow rate per unit thrust

Easy explanation: The specific thrust is defined as the fuel flow rate per unit thrust produced by the aircraft. The units of specific thrust are kg/N hr. The expression for specific fuel consumption is given by C=\(\frac{Q_f}{F_N}\) where Qf is fuel mass flow and FN is thrust produced by the aircraft.