# Homework Help: Aircraft Performance Question -- Berguet

1. Jun 30, 2014

### LaReina

1. The problem statement, all variables and given/known data
What cruise velocity should the aircraft fly to maximize the cruise range?
Aircraft mass (excluding fuel), m0= 14000kg
Mass of fuel, mf = 2500kg
Specific fuel consumption of aircraft engine, sfc = 2.8$\times$10-5 kg/N/s
Drag polar, CD = 0.02+0.08CL^2
Planform area of aircraft wings, S = 65m2

2. Relevant equations
Breguet Equation
Coefficient of Lift

3. The attempt at a solution
I am trying to find the coefficient of lift but there has been no given velocity. I then try to find the velocity but there is no given coefficient of lift. I feel like I'm going around in circles.
Cl=2L/ρV2S
L=W (14000+2500)$\times$9.81=161865N

Last edited: Jun 30, 2014
2. Jul 1, 2014

### Simon Bridge

Are you not assuming uniform level flight?
Does that not make the lift equation rather simple?

How about showing the details of the working, with reasoning, that you have already.