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Gnat SPAD has altitude hunting problems

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S.P.A.D. Aircraft - Coroplast design Discuss the growing area of S.P.A.D.S. (Simple Plastic Airplane Designs). Coroplast type aircraft, pizza box planes, etc..

Gnat SPAD has altitude hunting problems

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Old 11-22-2006, 06:46 AM
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3D Flyer
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Default Gnat SPAD has altitude hunting problems

My GNAT when flown straight and level has a problem with "hunting" for level. I suspect this is due
to the relatively sharp LE. Is this correct and can I just blunt it more to fix this?

Anyone else have this problem?
Old 11-22-2006, 09:59 AM
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MrGreenSpeed
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Default RE: Gnat SPAD has altitude hunting problems

Try reflexing the ailerons up just a little bit see if that helps.
Jeff
Old 11-22-2006, 12:23 PM
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rrh
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Default RE: Gnat SPAD has altitude hunting problems

Are you using anything bigger than a .15 on it?
Old 11-22-2006, 12:50 PM
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Default RE: Gnat SPAD has altitude hunting problems

yes, super tiger .19
Old 11-23-2006, 12:14 AM
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joe_weisman
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Default RE: Gnat SPAD has altitude hunting problems

I built one a few weeks ago with a 0.25LA. Had to strap the battery pack all the way back, right next to the rudder. It was pitching up in the maiden because I had too much ron reflex. Aligned the rons exactly with the fuse and it flies better.



My gnat is a somewhat strange little thing. It flips and slips in funny ways, but it isn't the plane for nice and relaxed flying. Cut the engine and it drops faster than a brick. I'll be moving its equipment to other things as soon as I find time to build them.

Joe
Old 11-23-2006, 12:23 AM
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Default RE: Gnat SPAD has altitude hunting problems

By the way, the trivial answer to your question would be to move the CG forward (or wing backward) a little bit to increase stability. I assume you're satisfied that this is not your problem?

Joe
Old 11-27-2006, 07:18 PM
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Stripes
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Default RE: Gnat SPAD has altitude hunting problems

There are Gnat plans out there showing a cg of 4 1/4 but most are happier at 3 3/4.
Old 11-28-2006, 06:06 AM
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Default RE: Gnat SPAD has altitude hunting problems

The aileron reflex suggestion solved the problem.

Thanks guys.

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