SO Plane Won't Recover after Collision

From: calgoddard <calgoddard_at_yahoo.com>
Date: Mon, 26 Jan 2009 17:42:13 -0000

Thanks Kurt and Bill for your suggestions.

As these are sixth graders I am coaching, I tried the simplest
solutions first.

Adding incidence to the main wing didn't solve the problem.

So I looked at the main wing LE spar. It did not seem too weak to me.

But I saw what looked like some wash-out on the outboard panel, i.e.
the LE was down a bit. There was also too much wash-in on the
inboard panel.

So the wing braces were adjusted to cure these apparent defects. The
inboard TE diagonal brace was uncemeted and re-glued to raise the TE
spar a bit on the inboard panel. A relatively long outboard diagonal
wing brace now supports the outboard side of the LE spar attaching
about two inches from the wing post. We kept the inboard diagonal
wing brace for the LE main wing spar where it was to begin with. Sure
the extra diagonal wing brace adds some drag and a little weight, but
these changes competely fixed the problem and my sixth graders were
very happy. I just know at the competition they are going to hit the
center score board or a light, or the ceiling so the plane needs to
be able to recover. The extra diagonal brace not only makes the wing
the right shape, but adds a little strength as well.

The plane came it at 7.19 grams after the fixes, which is still
pretty good for sixth graders. As you know, 7.0 grams is the minimum
weight according to the 2009 Wright Stuff rules.

Thanks again for your help.
Received on Mon Jan 26 2009 - 09:42:16 CET