Ground School Exam Questions & Question Banks

[Mzehmed]

Principles Of Flight Exam Question.

Hi guys, just a quick P.O.F question from me.

Question:

A 50 ton twin-engine aeroplane performs a straight, steady, wings level climb. If the lift/drag ratio is 12 and the thrust is 60000N per engine, the climb gradient is: (assume g=10m/sē).

I believe I have the correct formulae to work with as:

Gradient Of Climb = Thrust - Drag / Weight (x100)

Therefore we have;

Thrust = 120,000N (60,000x2)
Weight = 50,000 KG

Gradient Of Climb = 120,000 - (Drag)* / 50,000 (x100)

*At this point I am fairly lost and not sure how to calculate the drag to enter into the formulae. Just as extra info the options for this answer are:

a) 3.7%
b) 15.7%
c) 12%
d) 24%

Thanks for any advice.