Tuesday, December 30, 2008

Catapult launched glider: Sotich 8" CLG

This is a catapult glider design by Charlie Sotich. It's a quick n easy build and flies reasonably well. The plan is available from the Aeromaniacs site here (click on the pdf symbol next to Catapult!).

This one took me just over half an hour to make and came in at 2.7g including nose weight. Not bad for an 8" span model. She flew right off the board with an in built left turn. First flight was a promising 36s in cold weather, 8mph wind.

Alas, after about a dozen flights, I pulled the elastic back too enthusastically and shredded the right wing - the curse of small CLGs! I'm oddly pleased because it was the wood that failed, not the glue joint.

Great fun while she lasted.

All was not lost, as I decided re-utilise the fuselage for another, different, wing and see what I could learn from that

So here she is the next day with a conventional 3 panel wing made out of 1/8 balsa. Also now sporting carbon fibre tow on the sides to keep the fuselage stiff. Weight has gone up to 4.2g, but she still flies well. Polyhedral is 1 3/8" under each tip. Too much, because she Dutch wobbles in flight, but at least showed no tendency to spiral in.

Here's a photo of the underside. You can see the Al-foil tape that I've used to reinforce the wing-fuselage joint. So far, no more shredding!

I think the original is prettier. The modified version seems more consistent. Best flight today was just under 45 s in winter conditions, with no flights under 30 s.

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