Got a ? for you folks. I have a Great Planes CAP232 .40 with a OS .46 FX. My problem with it is when running straight and level and pull the elevator a little to much it goes into a violent snap roll. I have checked everything I can think of and cant figure it out. Both elevator halves are even and travel even up and down. The only way to get it to stop was use LOWER than recommended low rates and run a 11x4 prop to slow it down on top end. Is this normal or is something out of kilter? Thanks in Advance. Blacksheep

Sounds normal to me. If you try to loop or turn any model harder than it is able you will get a stall and at high speeds that generally results in the wing snap rolling the model.

It comes from a few causes. The first is the model being too heavy and with a high wing loading means that it's easy to push the airfoil way beyond it's maximum lift capability and it ends up stalling. The second is that you try to push the wing with too much up elevator and it rotates the model fast enough that the wing goes past it's maximum allowable angle of attack for the airfoil and again stalls the airfoil. The two are actually related in that any model of any wing loading has a given maximum allowable angle of attack for the wing and weight that will result in a snap roll. LIghter models will loop or turn tighter before it happens and heavy ones will have it occur with larger loops or more open turns.

This is why you see the fun fly and other very lightweight 3D models doing stupidly tight loops without falling out into a snap roll. They are so light that even at that size of loop they can generate enough lift to provide the rotation without exceeding the angle of attack where the wing stalls. Of course they also get into the flips and tumbles where they intentionally induce a stall and then maneuver in a post stall mode but that's a different story.

The issue can also be compounded by the selection of the airfoil or building inaccuracies. For example using a diamond shaped stock for the leading edge and not shaping it to the proper rounded shape will tend to induce a stall earlier than a properly rounded profile done to an accruate shape for the airfoil.

Thank you. Basically your saying its the idiot behind the sticks! At least I know the plane is ok. This is my first "scale" aerobat so I just wanted to know if it was me or the airplane. Thanks Again. Blacksheep

That's why they are called "Snap 232's"

In aeronautical terms, what you are experiencing is called and accelerated stall. When I was learning to fly full scale, my instructor kept pounding into my thick noggen, that a wing can stall at any airspeed and any attitude. A part of the design qualities of an aerobatic airplane, is to take advantage of, and incorporate some of these attributes, to make the airplane more aerobatic. Wing loading can certainly be a part of why the plane does this, however, it's likely it was designed into it. Toning down elevator at low rates might help.

I have the same plane 50 sx power. Mine will also snap, but only when excessive elevator is applied eg, full up at med to hi throttle. I think most scaleish aerobats will do this. This has nothing to do with the "snap happy" reputation Caps got - that was a low speed handling issue which this model does not have due to built in dihedral. Just tone down your elevator inputs. You'll find this plane will harrier with great stability in calm conditions and does great elevators any time!