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33% edge 540 snap problem

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Old 03-22-2003, 01:02 AM
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Default 33% edge 540 snap problem

Was wondering if someone could solve my problem?
My CG is slightly in front of the wing tube.
the problem i got is when i pull full back with 1/3 or more throttle in low rates which is 11 degrees of throw the plane drops the right wing, also in mid rates does the same thing only in high rates (3d rate) it doesnt do this. My elevator halfs are matched, the rudder trim is nuetral and the ailerons are dead even and matched to the wing. the plane is latterally balanced also.
Thanks for any input..
Old 03-22-2003, 01:39 PM
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Default 33% edge 540 snap problem

This problem is kind of hard to explain. If models are anything like full scale then it could be a stability problem. You CG is most likely in front of your center of lift. The tail's on fullscale aircraft produce a downward force which counteracts to tendancy for the nose to drop because the lift is behind the weight. It sounds almost like your creating an accelerated stall. When you yank back on the elevator your pitching higher than the angle of attack at which it stall in such a fast motion that it stalls right there. As for why the right wing drops all of the time, that's also somewhat tough to explain. It sound like you may have some area on your right wing that is causing it to stall first. If your leading edge on your right wing is sharper than the left, that would do it. To make airplanes more stable in a stall the wing needs to stall at the root first then progress out to the tip. This can be faked by adding stallstrips (triangle stock) near the root on the leading edge, this will disrupt the airflown first and cause the root to stall first. If your wing is built up, it could be warped. If the angle of attack of your wingtip on your right wing is higher than the root, it will always stall first. I know it's a long answer but it's all I can think of at this time.

-Kelly
Old 03-22-2003, 08:44 PM
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Default 33% edge 540 snap problem

How heavy is the plane?
Old 03-23-2003, 12:56 AM
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Default 33% edge 540 snap problem

thanks kelly. the wing is an arf wing pre-built by areoworks. foam laminated balsa
Old 03-23-2003, 12:57 AM
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Default 33% edge 540 snap problem

flynbrian the plane weighs 27lbs wing span 105 inch
Old 04-07-2003, 10:00 PM
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Default 33% edge 540 snap problem

kelly has a good point but the simple suggestion would be to make sure you are pulling the stick straight back and not back and over

How many times have you tried this? Is there a chance wind had anything to do with it? I have the same plane so I am just trying to compare it to what I have experienced. When traveling at slower speed and harriers epecially it will rock in the wind. But not when it is calm. Does it do it at wide open throttle?
Old 04-07-2003, 10:09 PM
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Default 33% edge 540 snap problem

problem fixed, thanks everyone.

I sealed my huge gap i had on the ailerons,
added weight to right wing, left wing was heavy
added nose wieght was slightly tail heavy
and added a little of up thrust on engine mount..
it wont tip stall at all through all degrees of throw now..

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