It seems like a easy question but I can't find the correct answer...

A 4 jet-engined aeroplane (mass=150000kg) is established on climb with all engines operating. The lift-to-drag ratio is 14. Each engine has a thrust of 75000 Newtons. The gradient of climb is: (g=10m/s?)

a) 1.286%

b) 12.86%

c) 27%

d) 7.86%

Climb Gradient (%) = (T - D)/W . 100

= (30.000kg - D)/150.000kg x 100

So we have to find Drag...

The only thing we know is D = L/14

and

L = W . cos X

L = 150.000kg . cos X

We still have to know... the climb angle.

A 4 jet-engined aeroplane (mass=150000kg) is established on climb with all engines operating. The lift-to-drag ratio is 14. Each engine has a thrust of 75000 Newtons. The gradient of climb is: (g=10m/s?)

a) 1.286%

b) 12.86%

c) 27%

d) 7.86%

Climb Gradient (%) = (T - D)/W . 100

= (30.000kg - D)/150.000kg x 100

So we have to find Drag...

The only thing we know is D = L/14

and

L = W . cos X

L = 150.000kg . cos X

We still have to know... the climb angle.

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