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The Belatrike Flies! But turns left...

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Foxflier View Drop Down
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  Quote Foxflier Quote  Post ReplyReply Direct Link To This Post Topic: The Belatrike Flies! But turns left...
    Posted: 06/Jan/2012 at 5:11am
Success today with my Belatrike.   

Three flights and she flies pretty good although I've got a left turning tendency I need to resolve.

I can see my biggest problem is launching. I've tried both rolling starts and hand launches and the probability of a poor launch seems about the same. I need some schooling on launching!

The left turning tendency has me a little stumped. I tried loosening the left brake an inch to no avail. I decided to try some right brake but didn't get a chance to test again. The only problem is the foil seems to fly better when it's turning left. When I hold right brake to go straight or to turn right the foil seems to become sluggish. Any ideas?? Could some AoA rigging difference from one side to the other cause this?

All in all it's a blast and definately a different flying experience. I've been flying fixed wing and some helis for many years but this is altogether different. Most difficult thing is relying on the throttle to control ascent / descent. Many of the videos I've seen with folks having trouble appears they're suffering from either not enough throttle control and / or not reacting to their foil's bad rigging and turning tendency soon enough.

Thanks for a great Trike!

Ted
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  Quote dodgemcopter Quote  Post ReplyReply Direct Link To This Post Posted: 06/Jan/2012 at 3:03pm
Look at too high KV motor (1000kv max) or too high prop pitch (6inch max) Its very hard to give helpful advise as there are so many variables but video's help us help you for sure
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  Quote Foxflier Quote  Post ReplyReply Direct Link To This Post Posted: 06/Jan/2012 at 11:02pm
Thanks. I'll have to try to get some video next time.

I really have the right side brake of the chute pulled down to try to correct the turn. I got to looking and I'm really wondering about P-factor as that would induce a left turn tendency on the trike. I'm running an 840kv setup on 4S with a 12x6 E-prop (regular prop reversed). Weighs 1.7kg. Plenty of thrust.

Does P-factor tend to be pronounced with trikes?

Regards
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  Quote Foxflier Quote  Post ReplyReply Direct Link To This Post Posted: 07/Jan/2012 at 4:37am
The more I think about it and look at the foil the more I believe the turn may be caused by an AoA difference...ie, less AoA on the left (or more on the right) that's causing more lift on the right side and inducing the left roll. I just can't believe P factor could result in such a pronounced left roll tendency.

Not enough AoA on the left would explain why when I hold right brake to compensate the chute seems sluggish whereas when I release the brake and do a left roll it seems to speed up. Am I thinking about this right? I'm assuming it doesn't take much change in the D-rings to cause a pretty good change in AoA. I'm thinking about moving up my forward two D rings to induce some additional AoA on the left side of the foil and see what that does.

Please tell me if I'm smoking something here!
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  Quote Kansas Scott Quote  Post ReplyReply Direct Link To This Post Posted: 07/Jan/2012 at 9:37am
Your left and right AOA are different.

I had the same problem as well as the AOA being to high. At launch with medium RPM, the kite would descent slowly with a slow right turn, I applied 10% more power and the kite nosed up to a stall and rolled hard right.

I lowered that 4th D ring (leading edge)and made sure thay were even on both sides. I hope the canopy strings are reasonably the same lengths.

I hope to test it soon.



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  Quote Foxflier Quote  Post ReplyReply Direct Link To This Post Posted: 07/Jan/2012 at 12:17pm
Yep, I readjusted adding a little more AoA to the left side by moving the A&B rings further up the bridle and I'm going to try it and see. I'm not so sure the risers are exactly the same length but I haven't measured them. Although it seems hand popping the chute up is only valuable to an extent it seems it may have helped. I'll find out and advise.
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  Quote Kansas Scott Quote  Post ReplyReply Direct Link To This Post Posted: 08/Jan/2012 at 7:53am
I lowered my AOA and adjusted my CG to a more flat trike.

After a few test popups and control line adjustments, I thru it.

It headed into a 5 to 8 knot wind, but was level and holding it's own.
I goosed up the power and it moved up and forwared nicely. I gave it some left and it turned and headed down wind in a hurry loosing altitude.
I slowly increased the power until it leveled out, then gave it a little more, and the prop blew up. Gravity took care of the rest.

I'm running the 35-36 1400kv motor with a 11X6 APC prop.

After straighting all the bent sheetmetal and replacing the prop I went back and tried again, This time on lauch, I ran the throttle up and again the prop blew up. A forensic evaluation showed that the prop hit the lower part of the tower. Partly the result of a bent motor mount.

My other theory is that the prop is flexing forward when I apply a quick burst of power.

What's a recommended prop to be sure that it's not flexing?

I'm already beefing up the motor mount.
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  Quote Svoboda92 Quote  Post ReplyReply Direct Link To This Post Posted: 08/Jan/2012 at 5:11pm
hi!

it could be caused too by torque reaction of the motor/propeller.


Edited by Svoboda92 - 08/Jan/2012 at 5:11pm
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  Quote Foxflier Quote  Post ReplyReply Direct Link To This Post Posted: 08/Jan/2012 at 9:47pm
If you're using the sheet metal motor mount supplied with the kit you'll need to reinforce it. I had terrible harmonic vibration with mine until I chucked that mount and bent a solid mount out of .063 6061. Worked perfect. No more flexing or vibe.

I did a lot of testing and launches yesterday and found that mine is an AoA problem. And I've found that you can't count on the risers being the same length across the foil. The right and left sides may be a little different. I think I may have mine close now. There seems to be a point where it doesn't take more than a few mm of movement of the D rings on the bridles to have a pronounced effect on the foil's performance. Particularly those forward rings.

Got more props on order so it'll be a few days for me. Seems like every kiss with the ground is a prop!   
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  Quote alphapilot Quote  Post ReplyReply Direct Link To This Post Posted: 05/Feb/2012 at 4:16pm
Believe it or not, P-factor IS a factor on these trikes, a huge one even. Depending on the angle of your trike(and your prop) compared to the flight direction(read relative wind) this might lead to uncontrolled flight. A way to reduce the effect is to add weight to the front of the trike so that it's hanging level instead of backwards. This will make the trike fly a bit faster as the thrust is now level instead of slightly up but this doesn't add up to the gained advantage in control. Hope this helps somebody out!

Grtz,

Edited by alphapilot - 05/Feb/2012 at 4:21pm
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