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Old 06-07-2019, 08:19 AM
joeteresi is offline
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Help!
Hanger 9 RV 4

I have been working on my RV 4 for several flights now. The plane climbs as soon as the throttle is increased. I have CG in the dead center of recommendation. I have also tipped engine down one washer thickness to try and compensate with no improvement. Can someone give me some ideas as to what may be wrong with this plane.
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Old 06-07-2019, 10:45 AM
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Could be stab incidence

It's a fat, flat bottom airfoil that produces a lot of lift and the more power you give it the more lift it creates.
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Old 06-07-2019, 03:45 PM
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I have the Saito 61cc on mine and with the nose weight of that engine it flies really nice... try some nose weight..
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Old 06-07-2019, 04:02 PM
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Yea, I forgot, its been a while since I fooled with mine.

The CG in the manual is too far aft, might work fine with AS3X but it flew a lot better after we put some weight up front.
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Old 06-08-2019, 07:26 AM
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Thanks for the suggestions. I'll give it a try with some more weight up front. I have a 40 twin in it so you would think that's enough weight. Batteries are just behind fuel tank. This thing is driving me crazy.
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Old 06-12-2019, 05:41 PM
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I relocated both batteries to just next to fuel tank. Fly's the same just keeps on climbing. CG is way in front of where it should be now and still has the problem.
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Old 06-12-2019, 06:16 PM
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What's your elevator trim showing after set for level flight? How's it fly inverted?
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Old 06-12-2019, 08:26 PM
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wrongwayfeldman
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I think you need to take that washer out from the bottom and add to the top
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Old 06-13-2019, 09:01 AM
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Quote:
Originally Posted by ponyboy082662 View Post
I think you need to take that washer out from the bottom and add to the top
Washers are at the top to drive thrust down. Thanks
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Old 06-13-2019, 10:56 AM
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wrongwayfeldman
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Quote:
Originally Posted by joeteresi View Post
Washers are at the top to drive thrust down. Thanks
I miss spoke....if you add washers to the top it causes the thrust to appear downward but it presents the wing angle up which is why your plane climbs. I had this issue on a bipe. It flew like crap and On landing if you blipped the throttle at all it immediately climbed. I put a thin washer under the bottom 2 standoffs and it flew great after that....give it a try ...if it's better then go a bit more till it's not
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Old 06-15-2019, 09:15 AM
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Thanks to all for the input
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Old 06-15-2019, 06:27 PM
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Quote:
Originally Posted by nappyroots2182 View Post
What's your elevator trim showing after set for level flight? How's it fly inverted?
Tim at level flight is elevator down many clicks. The way it flies I wouldn't go inverted.
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Old 06-15-2019, 07:51 PM
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Try more nose weight
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Old 06-15-2019, 08:47 PM
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Excessive down trim is a sign of a tail heavy plane
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Old 06-15-2019, 08:51 PM
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wrongwayfeldman
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It could be totally wrong but I believe it's your engine thrust angle. In level flight your engine is what's actually flying level not the plane. With too much downward thrust it changes the wing angle upward which is why your plane wants to go up and also why you need downward elevator trim to compensate for it. Like I said before I had the same problems your having and altho it sounds counterintuitive ....a little up thrust is what fixed mine. Not being there to examine it for my self means I may be in left field. Hope you get it figured out and good luck
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