A CAI Raptor ,on its first flight, fluttered and crashed this weekend. This plane was one of the best looking Raptors I
had ever seen. It was a single seat, painted like a Blue Angle.
NICE


Here is what happend. The whole wing fluttered, on both sides.
It happened at ~180, the plane slowed down
when the flutter started, nothing left the plane but
it was uncontrollable and nosed down and hit the
ground at about ~100. It did not roll much and the outer
wing sections, past the gear were making a very loud flutter sound and you could easily see the wings were a blur.

The first reaction was the aileron, linkage broke,
ect, but I saw the linkage, and I know the guy who built
it. All the equipment was top notch. Next to no slop ect..
This should not have happened. I am confident it was not the
builders fault.

This is not the first time this has happened to Raptors
and I want to know WHY. I design a lot of planes and
I would not want this to happened to me. Since CAI
is no longer selling planes, there should be no harm in
trying to figure out want went wrong.

The (rumor) is 3 of 4 CAI F-100 did the same thing. WHY ?

I have a theory.

Think about this. Your in a 747 sitting even with the wing.
You can see the wing moving up and down, and twisting.
If the 747 were to pull 2g's, the wing would bend up
and also twist some to give it washout.

What would happened if instead of washout as with wing
bent up, the wing would twist and produce wash in ?
I think the wing would start to flutter or just break off.

So... I clear you must build a wing where as you load it,
and it is bent it up, it twists in a manner to decrease
the AOA near the wing tip.

All CAI wings were molded top and bottom with glass and
balsa witch made a very nice, stiff, strong wing. This made
a hollow wing witch used a laminar flow airfoil where
the thickest point was farther back than most model planes.

All wings will twist, loaded with G forces they twist around
the axis of rotation for that wing. Its just a line that
the wing will twist or rotate around. Remember, at 200mph
it only takes ~0.2 deg AOA to fly.

I think the axis of rotation, was behind the center of lift....

Was this a problem in the past with full-size aircraft.. ?
Does anyone hear of this problem before.. ?

Eddie Weeks
http://www.corpcomp.com/weeks1/