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Old Oct 19, 2014, 07:29 PM
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addictedtoplanes's Avatar
Canada, ON, Guelph
Joined Jun 2012
699 Posts
Help!
Problems with tomhe Mig-29

I recently scaled down the tomhe Mig29 by 50%, for UMX Sbach (no as3x) guts. I am using the stock motor, with a GWS 4040 with 0.5 cm off of the tips, spinning clockwise. After launch, all it will do is fly a tight counter-clockwise circle. I have tried right, left and center thrust, with no result. Any ideas?!?!?! Other than the turning, it flies great, and I would like to keep it.
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Old Oct 19, 2014, 09:56 PM
Registered User
Hampton, VA
Joined Mar 2009
1,288 Posts
Kwel!!! Another Half Pint. If I'm not mistaken, GWS props should spin counter-clockwise (CCW), unless you're using a counter rotating prop. You should have the lettering on the prop, facing the front of the plane. Another thing to watch out for, is the lateral balance. Since your prop is spinning CCW, you should have your heaviest components on the right hand side of the plane, when viewing from the rear. I generally have my receiver on the left, ESC on the right, and if the batt has to favor one side, it'll be the same side as the ESC. This helps counter act torque. Also, verify that the vert fuse pieces are straight and your rudders are squared with the vert fuse. The same applies to the belly pan pieces.

Check and make sure your tailerons are not flexing on ya, along with the push rods. I build my half pints with 3mm or 2mm depron. Sometimes I'll use 2mm CF rods or spilt a 3mm x 1mm CF flat, to help support control surfaces.

What's the specs on your build? Here's a trick I do sometimes with Half Pints. I mod the spacing of the rudders and belly pan to fit a 40xx size prop. Go to Attachments in my blog. You'll find a bunch of Half Pints.

Ksqm
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Old Oct 20, 2014, 02:07 AM
Fremont, CA
United States, CA, Fremont
Joined Jan 2009
1,687 Posts
A CCW prop will exert a CW torque on the plane, so the heavy components should be on the left (if I'm not mistaken).
Sometimes a hard-to-control plane is tail heavy. Try making it a bit nose heavy and see if it helps.
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Old Oct 20, 2014, 08:35 AM
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addictedtoplanes's Avatar
Canada, ON, Guelph
Joined Jun 2012
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Just a clarification, the prop spins clockwise when viewed from the rear. The receiver is directly on the centerline but the battery is on the right side of the plane. The prop is also oriented correctly. It has a 14" wingspan, is 19" long and weighs 50 grams. The tailerons may be flexing a little.
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Old Oct 20, 2014, 11:50 AM
Fremont, CA
United States, CA, Fremont
Joined Jan 2009
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Could you show a top view of the plane and your current CG?
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Old Oct 20, 2014, 03:47 PM
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Canada, ON, Guelph
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Here's the CG
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Old Oct 20, 2014, 06:32 PM
Fremont, CA
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Looks OK to me, but shift the batteries 1/2" forward and see how that changes authority.
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Old Oct 20, 2014, 07:19 PM
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I will give that a shot.
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Old Oct 20, 2014, 07:45 PM
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I just gave her a toss in the front yard, and the forward CG really helped. I also found that it is extremely sensitive to the batteries lateral position. Put it on the left side of the plane, and it yaws left, and vice versa. I will put the battery in the center for now, and give it some trim. Thanks for the help!!
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Old Oct 21, 2014, 02:19 AM
Fremont, CA
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Great! Glad it helped. A tail heavy plane is a real bummer :-(
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