Question

Which of the following is the correct equation?

(a) SAR=\(\frac{C}{V}\frac{L}{D}\frac{1}{W}\)

(b) SE=\(\frac{C}{V}\frac{L}{D}\frac{1}{W}\)

(c) SAR=\(\frac{V}{C}\frac{L}{D}\frac{1}{W}\)

(d) SAR=\(\frac{1}{C}\frac{L}{D}\frac{1}{W}\)

The question was posed to me during an internship interview.

The query is from Range and Endurance for Aircraft with Thrust Producing Engines topic in division Cruising Performance of Aircraft Performance

Answer 1

Correct option is (c) SAR=\(\frac{V}{C}\frac{L}{D}\frac{1}{W}\)

Easy explanation: The equation for specific air range is given by SAR=\(\frac{V}{C}\frac{L}{D}\frac{1}{W}\) where V is true airspeed, C is specific fuel consumption, L is lift, W is weight. The significance of first fuel flow law is that the specific fuel consumption is constant.