Question

Which of the following is correct for a typical glider?

(a) Drag D = W*cos (gamma)

(b) Drag D = W*arcsine (gamma)

(c) Drag D = W

(d) Drag D = Thrust T

I had been asked this question in a job interview.

My doubt stems from Flight Mechanics in section Performance and Flight Mechanics of Aircraft Design

Answer 1

Correct answer is (a) Drag D = W*cos (gamma)

The explanation: Above equation is used to provide information about drag of atypical glider. Drag can be given by, Drag D = W*cos (gamma) where, D is drag, W is weight of the glider and gamma is the glide angle.