University:
Massachusetts Institute of Technology
Course:
16.100 | Aerodynamics
Academic year:

2020
Views:

407

Pages:

2
Author:

Heather Stanley

Brequet Range Equation V t=tf W=Wf t=ti W=Wi Range tf Range = ∫ Vdt ti In level flight at const speed: L = W , Lift = Weight T = D , Thrust = Drag The aircraft weight changes during flight due to use of fuel. Relate weight change to time change: dW dt dt fuel weight dt =− time fuel weight T dt =− time T dW = The quantity: fuel weight 1 time T is known as the specific fuel consumption or sfc. It has units of: sfc units = lb( fuel ) force or lb − hr force − time ⇒ dW = − sfc iT dt Wf ⇒ Range = − ∫ Wi V 1 dW sfc T But since T = D and L = W we have: Wf Range = − ∫ Wi V L dW sfc D W This is the general form of the range equation. The Breguet range equation is V L is constant for the entire flight. In that case: found by assuming that sfc D Wf Range = − ∫ Wi Breguet range equation: Range = Wf V L dW V L dW =− sfc D W sfc D W∫i W V L Wi log sfc D Wf

Brequet Range Equation

of 2

Description

Free up your schedule!

Take 5 seconds to unlock