Chad,

We went thru about 5 Hellraisers, then moved on to other birds.

I would look for wing issues first. Correct as necessary.

a. Are the wings flat?... when you look down each wing from the end, are they "perfectly" flat, with no twist or bow.

b. Are the ailerons syncronized?... when you set one aileron FLAT to the wing, are all three others flat to the wing.

c. Is the horizontal stabilizer parallel to the wings?... when you look from the front or the back, you would see mis-alignment.

d. Are the two Elevator halves level with each other?... if you tape on some light straight item, like a balsa stick, on the surface of each elevator, are the sticks parallel when looking from the side?

e. Does the fuse have a twist or bow in it?

If none of these things are apparent to a noticable degree, you may have the dreaded HellRaiser Wing twist hula-hula happening in flight. What we found is detailed in the big HR thread [link=http://www.rcuniverse.com/forum/m_1970740/mpage_1/key_hellraiser/tm.htm]HERE[/link], but to summarize:

The top and bottom wings are not well braced to each other, and the top wing is not well connected to the fuse at the center kabane. When in flight, particularly at higher speeds, the top wing twists and rolls out of position in the yaw axis (twisting as look down on the plane). The drag on the wings holds it, and even compounds the problem, until you cut throttle or crash.

Hold the fuse, and push on the front of the upper wing leading edge at the end, you'll see the whole wing assembly roll and twist out of position. That's happening in flight... partial or total loss of aileron/roll control when it happens. Yours is probably doing it, but not really badly. I finally figured it out when I could see it in the air while it was flying straight away from me.

We added ice-cream sticks up thru the top of the fuse along the back of the Kabane thru the top wing, and glued it liberally with epoxy. We also ran secondary CF guy-wires from the front of the outer kabane at the top wing to the trailing edge of the lower wing so there was a front-to-rear offset to the new guywires. That really locked the upper wing in place, problems solved.

Hope that helps...