Xfoil suggests that the wing will stall when the local AOA reaches about 17.75 degrees, with the flaps up. But note that the local AOA will be different at each part of the wing, due to the upwash that occurs ahead of the wing. The local AOA will be highest at the inboard part of the wing, so the stall will start there. It is hard to know how much the upwash will be without doing some sort of wind tunnel work, or CFD analysis, so it is hard to say at what fuselage AOA the inboard part of the wing would reach 17.75 deg local AOA.

The wing will stall at a lower AOA when the flaps are down. Xfoil suggests that the stalling AOA is reduced to about 10.7 with 40 degrees of flap, but I have a hard time believing that the actual reduction in stalling AOA would be that much.
 
alpha

Kevin, thanks for that. I was interested because yesterday my -4 sat on its wheels for the first time and the angle of the fuse looked quite high. But the 10.7 degrees you quote would appear to be in the right ballpark since WITHOUT the engine/prop it is sitting at 13.3. Not sure how much it will reduce onece the engine is there but it is about right if it is to stall with flap in a 3 point attitude.

Am I right in thinking it is close to the point where it would not lift off without first raising the tail? I guess ground effect sorts that anyway?

Just idle curiosity.

Cheers.
 
The predicted stall AOAs from xfoil are for an airfoil that is out of ground effect. There is some evidence that the stalling AOA is reduced somewhat when a wing is in ground effect. This evidence comes from aircraft doing VMU testing that experienced wing stall at an AOA lower than the wing would stall at altitude. The reduction in AOA at the stall in ground effect seems to be something of the order of 2 degrees on aircraft that I am aware of. Mind you, the data I am aware of is from aircraft with swept wings, and advanced airfoils, so the reduction in AOA at the stall may be quite different on an RV.

I've never seen any reports that suggested that it was possible to get a full stall landing in a tailwheel RV. All reports I have seen say that the tail wheel hits first if you do a full stall landing, as the stalling AOA is apparently greater than the pitch attitude in the three point attitude. Now is usually the time when someone chips in and tells me that I am full of it, and that their experience is different :)
 
Nope; You are NOT full of it.

If you reach full stall attitude while landing an RV (airplane), the tail WILL hit first. If it doesn't, your mains are too long.
 
No full stall landing

I fly a -3 and I have only landed full stall once, and the tail does land first, followed very quickly by the mains with a very hard bounce. :eek: The best way for me to land is, establish a shallow 3 point and wait, till just before the mains touch, and then alittle back pressure. Works every time. (for me, actual results may vary) :rolleyes:

Mike RV-3 N87LB flying
RV-4 N742MC building
 
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