Question

What is Brequet Range expression?

(a) R1 = \(\frac{D}{C}\frac{L}{V}\) ln ω

(b) R1 = \(\frac{1}{C} \left[\frac{2W}{\rho S}\right]^{\frac{1}{2}} \frac{C_L^{\frac{1}{2}}}{C_D}\) ln ω

(c) R1 = \(\frac{1}{V} \left[\frac{2W}{\rho S}\right]^{\frac{1}{2}} \frac{C_L^{\frac{1}{2}}}{C_D}\)  ln ω

(d) R1 = \(\frac{V}{C}\frac{L}{D}\) ln ω

This question was addressed to me in an interview for internship.

Asked question is from Cruise Method 1 topic in division Cruising Performance of Aircraft Performance

Answer 1

Correct option is (d) R1 = \(\frac{V}{C}\frac{L}{D}\) ln ω

Easiest explanation: Brequet Range expression is given by R1 = \(\frac{V}{C}\frac{L}{D}\) ln ω where V is true airspeed, C is specific fuel consumption, L is lift, D is drag, and ω is fuel ratio. This Brequet Range expression comes in the cruise method 1.