stunthanger.com
General control line discussion => Open Forum => Topic started by: Russell Shaffer on November 26, 2016, 10:55:16 AM
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This has probably been tried so rather than repeat mistakes or re-invent the wheel, does it work to add tip weight to both wing tips? My thinking is that on a light 35 sized plane that weight added equally on both tips (at the CG) would add inertia and resistance to rolling without seriously harming the turning capability. For my 37 ounce Fancher Medic, perhaps 1 ounce on each tip? Hopefully Ted will chime in here. (I just went up and changed the thread title to attract him.)
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Don't put the weight at the wingtips, mount it somewhere close to the CG on the fuselage. But if the plane is having trouble on real windy days, go to shorter lines.
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Simply adding weight would not benefit you and in fact could cause more problem than you were trying to solve. (Ted may have different ideas about his ship but in general) Overall larger airplanes do better as a sum of weight, power and scale but it's not the same to just add weight. Sometimes just a touch of added tip weight- maybe up to 1/4 ounce and moving the leadouts back a tiny amount helps in wind if it was trimmed well in light air. Flying a bit faster by the needle, prop pitch or shorter lines will accomplish more. Some times the better part of valor is to just leave the plane in the car unless it's a must-do competition flight.
Dave
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If I remember right I think he talked about adding 6 ounces to the CG.. That was a long time ago on SSW. Just message him and ask.
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We all fight hard to remove weight from our stunters!
Ballast is for big gliders.
Floyd
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We all fight hard to remove weight from our stunters!
Ballast is for big gliders.
Floyd
I know this and you know this but I was dressed down over it.
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This has probably been tried so rather than repeat mistakes or re-invent the wheel, does it work to add tip weight to both wing tips? My thinking is that on a light 35 sized plane that weight added equally on both tips (at the CG) would add inertia and resistance to rolling without seriously harming the turning capability. For my 37 ounce Fancher Medic, perhaps 1 ounce on each tip? Hopefully Ted will chime in here. (I just went up and changed the thread title to attract him.)
That's possibly true, however, the previous discussion (where he added 8 ounces to the CG of a Tucker Special for tremendously improved performance) involved increasing the line tension without increasing the control loads to give more margin over the Netzeband wall. That very likely doesn't apply to the Medic, since the control loads are not likely to be anywhere near the edge of the capability (unless you have something very strange in the control setup). 37 ounces isn't particularly light even for a good engine, if it has a 4-2 break engine, then it's not at all light. Bob Hazle's Medic was much less prone to roll/yaw in turbulence than the original Doctor, precisely because it was "denser" and once we got it trimmed it flew very well.
I would guess there is some other trim issue, rather than just "too light".
If you want to try it, put some hinge=sealing tape over the finish, clean it off with acetone, then use stick-on weights over the tape, right up against the fuselage on both sides, top and bottom. I wouldn't recommend putting it at the tips because while it will slow down the rolling motion, it will also take much longer to die away. Adding weight at the CG will increase the line tension and permit more roll stability from the lines. the Hinge sealing tape will come off - the stick-on weights will leave the residue behind.
In this case, it would surprise me if it helped any, but don't let that stop you from experimenting.
Brett
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Thanks, Brett and all. I should have said turbulence rather than wind. I was trying to come up with a simple way to cut down on wing rocking and I didn't consider that while the roll might be slowed down it would also take longer to stop. The wind conditions I was trying to fly in were severe enough to make many people pass on second flights so the Medic wasn't actually doing poorly at all. I don't believe the airplane has any real trim issues - other people have commented that it looks good in flight. I don't plan to pile on lead just to increase the weight, that wasn't my intent. Power is an LA25 with an APC 9-4 and the gaps are sealed so I guess I'll just learn to fly better.
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Thanks, Brett and all. I should have said turbulence rather than wind. I was trying to come up with a simple way to cut down on wing rocking and I didn't consider that while the roll might be slowed down it would also take longer to stop. The wind conditions I was trying to fly in were severe enough to make many people pass on second flights so the Medic wasn't actually doing poorly at all. I don't believe the airplane has any real trim issues - other people have commented that it looks good in flight. I don't plan to pile on lead just to increase the weight, that wasn't my intent. Power is an LA25 with an APC 9-4 and the gaps are sealed so I guess I'll just learn to fly better.
I had assumed that it was an issue in turbulence. Airplanes with constant-chord wings are more prone to that than tapered wings and this was an issue with the originals, although you could always get through the corners.
With adequate power, which you have, I think it would be worth a few ounces at the CG just to see what happens. You can always take it back off if it doesn't help.
Brett
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It seems to me that some designs just fly more stabily in turbulent air. I recall watching Reuben MacBride and his son, Steven, flying at Brodaks years ago (I think I was judging their flights). Reuben had a profile Pathfinder that seemed to be rolling quite a bit in the turbulent air. Steven's Evo flew like it was on rails in the same air. I've also noticed that Twisters seem to bounce around a lot. Is it the flat tip-plates?
Scott
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I once saw a stock Ringmaster fly very well in really poor conditions. Thin tapered wing and a LA25 and placed midway in Advanced. It looked good and cut through the turbulence well.