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Junkyard Dog Tip Stalls

Old 04-06-2007, 10:17 AM
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Default Junkyard Dog Tip Stalls

I built a junkyard dog, her name is "Peace". I had considered naming her POS which stands for "Piece of Salvation" but changed my mind for obvious reasons. "Peace" is a fuse from what I think was a Gentle Lady that I wrecked and a wing that remained from an Easy-Glider Electric that I turned into crumbs. She has a 2410-09 motor with a 1800 mAh 3 cell Li-Po installed and a prop that is entirely too small for the moment. She glides amazingly well as long as she is flat, but tip stalls fiercely at the slightest turn. How can I correct this? Also, what would be the largest prop I could use for "Peace" without burning up the motor?

Thanks!

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Old 04-06-2007, 11:14 AM
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Default RE: Junkyard Dog Tip Stalls

Well, you may have a number of problems causing this.

First, are you coordinating your turns well? Do you push rudder into the turn?

What bank angle are you using? The most spin prone turn angle is between 10 and 20 degrees. This a turn of this bank, you have the largest differential of speed between the inside and outside wing tips. If you are flying near stall, this turn angle will make this tendancy more apparent plus the extra wingloading from the turn may put you over the top of a stall. As the angle steepens further and the turn is properly coordinated, the nose drops and it picks up speed keeping a stall from happening. This is good and bad. It prevents stall but can put you in a spirial dive. This can overstress the wings of some gliders.

How fast are you flying? Are you just above stall speed? I think many people have a tendancy to fly gliders too slow trying to reduce sink. If you can get a visual estimate of the stall speed, add 50% more speed and that will probably be a good pace for you.

No input on your prop question.
Old 04-06-2007, 11:55 AM
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Default RE: Junkyard Dog Tip Stalls

This ship has no ailerons so bank angle is much less controllable unless I want to make long sweeping turns. I have several sailplanes and I do not have tip stall issues with them, even the ones with no ailerons. After reading up on tip stalls, I am leaning toward the tapered wing tips along with slight washout as being the culprit. I am going to see if the local hobby shop has any EPP foam I can use to modify the Easy-Glider wing to have better washout and blunt wing tips. I will report as to whether or not this fixes the issue.

Cheers!

A

Old 04-06-2007, 12:43 PM
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Default RE: Junkyard Dog Tip Stalls

It is true that tapered wing are prone to tip stalling more than square wings. Some washout can help this too. Mabe 1 degree would be nice depending on taper.

Does the rudder not let you have a steeper roll angle? Is the wing loading higher with the GL fuse than it was with the stock fuse? You also may need to reduce your elevator throw if the plane is heavier.

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