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General control line discussion => Open Forum => Topic started by: Paul Taylor on March 09, 2017, 09:02:00 PM
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If the plane gets light on the lines at the top of overhead 8 will moving LO forward help?
What is the side effect?
Thanks
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I would first want to know what your power system is, does it get light anywhere else in the pattern?
The overheads will show up a power system that is lacking In my experience..
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Paul, Mark has a lot of it- power can cure or cover many things. Don't know your airspeed but if you are too slow you might step it up a tad. To your question moving the leadouts forward may help if they were too far back to start with. Otherwise you might move them back in small steps to see what happens. When the plane gets light overhead either the whole airplane is trying to sideslip down with gravity (speed vs weight) or the nose is turning inward. That is aggravated if the airplane is nose heavy. Moving the CG back some and narrowing the handle line spacing if need be will help. Another factor in that particular spot in the pattern is fuselage/rudder side area behind the CG. It can act to weathervain in the head-on wind right there and the top of the vertical eight or hourglass. Here's where the extra power and a little engine offset is helpful. Don't give thought to rudder offset. While it might help get you through at this spot, it creates a bunch of other trim problems elsewhere. Clean flying lines also help. Reduce drag and friction when she IS a little light up top. Moving leadouts forward will help if they were too far back causing the ship to crab outwards slowing it down going over the top then reacting even worse as a weathervain. Hope this helps.
Dave
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Another way to check if it is the leadouts is to do some tight loops down low. If the leadouts are too far back(as to being slightly far back) the plane will show you the outboard wing tip whether its and inside loop or an outside loop.
If it doesn't roll on low loops it won't if they are up high. Then, as Dave T. says, it's more likely the CG-leadout positions. If you get the leadouts too far forward for the CG location the plane will also get light up high but not so much down low.
A little extra speed and/or making sure the engine is delivering more power up high(4-2 break) will also help a lot. Most stunters fly 52-55mph. At that speed if the air is moving fast enough to make a normal flag standout without flapping it's just on the borderline of anyone having a good time flying.
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Could be line length too.
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How about slightly more tip weight??
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Any of the above! I improved mine, some with tipweight and some by adding pitch to the last 1.5" of the prop blades. D>K Steve
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How about slightly more tip weight??
Maybe, but leadouts or power are more likely culprits. I'd do the leadout thing first, as it's the easiest thing to try (assuming you have adjustable leadouts). Theh problem you're seeing can be caused by the leadouts too far forward or too far back, so try moving them one way and if it makes it worse try moving them the other.
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so, are you going to share what the plane is, what lap time it is running when it gets light, are you sure you are doing the manuever in the proper place with respect to the wing, are you confident you are not making the loops to small, do you have confidence the power system is delivering power properly
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And don't move the lead outs more than 1/8" at a time..