Hello Guys, a rookie question here. I've been designing a plane in XFLR5 and analyzing it for sometime and I saw that my plane's Cp is in front of Cg. But when I searched the internet it says that Cg needs to be in front of Cp. Now what should I do? can anyone explain pls.....
Solved Cp and Cg position problem (XFLR5)
- Thread starter Arun_V
- Start date
quorneng
Master member
Arun
With the Cp in front of the Cg the lift will cause the plane to raise its nose. This will create still more lift raising the nose even more. It is unstable.
With the CP behind the CG the lift will tend to cause the nose to fall reducing the lift.
Be aware the CP moves as the angle of attack changes so a plane can still be unstable even with the CG behind the CP.
The CP is more or less fixed by the design of the wing so the CG is only thing you can adjust by moving weight about.
Note the CG position is quite sensitive to the plane's stability. Unless someone has found it out all ready for the design it will require some 'trial and error' to find the best position that suits how you want the plane to fly.
With the Cp in front of the Cg the lift will cause the plane to raise its nose. This will create still more lift raising the nose even more. It is unstable.
With the CP behind the CG the lift will tend to cause the nose to fall reducing the lift.
Be aware the CP moves as the angle of attack changes so a plane can still be unstable even with the CG behind the CP.
The CP is more or less fixed by the design of the wing so the CG is only thing you can adjust by moving weight about.
Note the CG position is quite sensitive to the plane's stability. Unless someone has found it out all ready for the design it will require some 'trial and error' to find the best position that suits how you want the plane to fly.
