Aerowerx
Well-Known Member
I have been playing around with flaps in my virtual wind tunnerl.
In XFLR5 the flaps are active only when doing a stability analysis (unless you want to define a fixed flap airfoil, then it would work in the static analysis).
What it does is find the speed and AoA to get a pitching moment of 0.0. Then goes to the next flap increment and repeat.
I can't figure out what I am seeing. It starts out as expected with the speed dropping and CL increasing, and then reaches a flap deflection where it reverses and the speed starts increasing again. This is supposed to be a self trimming flap (no pitch change with flaps), and the AoA is changing by about 2 degrees.
Can anyone explain this? Why the increase in speed at higher flap deflections? Maximum flap deflection is 20 degrees.
In XFLR5 the flaps are active only when doing a stability analysis (unless you want to define a fixed flap airfoil, then it would work in the static analysis).
What it does is find the speed and AoA to get a pitching moment of 0.0. Then goes to the next flap increment and repeat.
I can't figure out what I am seeing. It starts out as expected with the speed dropping and CL increasing, and then reaches a flap deflection where it reverses and the speed starts increasing again. This is supposed to be a self trimming flap (no pitch change with flaps), and the AoA is changing by about 2 degrees.
Can anyone explain this? Why the increase in speed at higher flap deflections? Maximum flap deflection is 20 degrees.
