Question

What is the value that maintains maximum rate and minimum power speed of the aircraft?

(a) 1/\(\sqrt[4]{3}\)

(b) 1/\(\sqrt[3]{3}\)

(c) u^2/\(\sqrt[4]{3}\)

(d) u^2/\(\sqrt[3]{3}\)

The question was posed to me during an internship interview.

I'd like to ask this question from Climb and Descent Performance with Power-Producing Engines topic in section Climb and Descent Performance of Aircraft Performance

Answer 1

Correct choice is (a) 1/\(\sqrt[4]{3}\)

The explanation is: At the maximum rate i.e. dv/du=0 the value of u=1/\(\sqrt[4]{3}\) which is the minimum power speed. The rate of climb is given by λ-\(\frac{1}{2}\)[u^3+u^-1]=Emaxv where λ is dimensionless power, u is airspeed and Emax is endurance.