Question

Which of the following is the correct equation for longitudinal performance equation of motion?

(a) \(\frac{\eta P}{V}\)=D-Wsinγ2+mV

(b) \(\frac{\eta P}{V}\)=D+Wsinγ2-mV

(c) \(\frac{\eta T}{V}\)=D+Wsinγ2+mV

(d) \(\frac{\eta P}{V}\)=D+Wsinγ2+mV

The question was posed to me in an internship interview.

I'm obligated to ask this question of Power Producing Power Plant topic in chapter Aircraft Force Systems and the Equations of Motion of Aircraft Performance

Answer 1

Right option is (d) \(\frac{\eta P}{V}\)=D+Wsinγ2+mV

Easiest explanation: The correct equation for longitudinal performance equation of motion is \(\frac{\eta P}{V}\)=D+Wsinγ2+mV where η is propeller efficiency, V is true airspeed, P is shaft power, D is propeller diameter, m is mass flow rate, W is weight.