Question

Helical tip speed is given by ____________

(a) \(\sqrt{Vtip^2+ V^2}\)

(b) 2*ᴨ*d

(c) CL*d

(d) Drag*Lift

I had been asked this question in an internship interview.

The above asked question is from Propulsion in portion Propulsion and Fuel System Integration of Aircraft Design

Answer 1

Correct answer is (a) \(\sqrt{Vtip^2+ V^2}\)

Explanation: The helical tip speed is given by, (Vtip) helical = \(\sqrt{Vtip^2+ V^2}\). The tip of propeller is following a helical path through air. At sea level helical tip speed of wooden propeller should be below 850 fps typically.