# Lift and Drag Which frame of reference?

1. Apr 4, 2014

### phys_student1

Lift and Drag....Which frame of reference?

Hi,

When expressing the Lift and Drag acting on an airplane as:

$$F_{lift}=qSC_L$$
$$F_{drag}=qSC_D$$

where q is the dynamic pressure, S is the wing ref. area, and C's are the lift and drag coefficient.

My question: Some sources, like this one, claim these equations are 'defined' in stability frame {S}, while other claim they are in wind frame {W}. In either case you'll use a rotation matrix to go back to body frame {B}, but this matrix will differ whether going from W->B or S->B, wo which is correct?

2. May 4, 2014

### Greg Bernhardt

I'm sorry you are not generating any responses at the moment. Is there any additional information you can share with us? Any new findings?

3. May 14, 2014

### phys_student1

Not really. I still do not have answer.

4. May 14, 2014