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General control line discussion => Open Forum => Topic started by: Dick Sarpolus on January 18, 2007, 06:25:20 PM
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Here's a not serious experiment with Side Force Generators, or how to waste some time. Baseline airplane design was a half-a size 250 sq. ins. electric powered mostly foam airplane, I know, not serious stuff. But this setup, on 40' of .008 cables, will fly through all the pattern maneuvers. No, not on a serious competition level, but it will fly, on a fun basis, through all the pattern maneuvers.
So I built one with SFGs, top and bottom of both wings, similar to the arrangement that works on R/C aircraft. Flew the plane a few times, said hey this thing stays out on overhead 8s, flies through the clover, it does okay. Then I thought about it and realized it flew exactly the same way without the SFGs. Further thought, on an R/C ship where you roll the wings vertical with ailerons and put in top rudder for knife edge flight, yeah, the SFGs provide additional side area to help with knife edge maneuvering. But on C/L, our airplanes already stay out on the end of the lines through all the maneuvers, so who needs SFGs.
But it's fun to try stuff.
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Well personally, I will admit to thinking about SFGs myself. The advantage I percieve is the gain in line tension you could get with slower lap times. I beleive the physics have already been displayed and I am not that adapt at calling up formulas, but line tension is basically a result of airspeed and weight. If you slow the plane down, you begin to lose tension. by having effective SFGs you could regain some of this tension while flying at a slower airspeed. This of course allowing more time to "fly" the manuevers. of course, more drag hence a need for more power,,, the cycle continues
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SFGs provide the force relative to airspeed just like any other serodynamic device. They would increase the line pull at ALL times, not just when flying slowly. And of course, the drag would also increase.
But why not go for it? They look kind of cool.
don Burke
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Two Fierce Arrows a 400 and a 600 with side force generators.
Willis ;D
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Maybe they should be made to move like a Rabe rudder?
RO
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YEAH! now were talking Rabe style SFGs,, another trim thingie to play with way to cool.
Don of course you are correct, they would change the force generated with speed, my point being that if you could reliably generate some additional side force you would be able to slow the airspeed down some and still maintain reasonable line tension
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There is something to be said about side area. I was flying my modified Time Machine when I hit my own wake in the triangles. Just missed splat, but it knocked off the rudder,all that was left was the little piece of vertical stab.I then tried to fly it a couple of more times and it would not do the overhead maneuvers. This was interesting to me. That was my experiment.
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I have also thought for a long time that the SFG could also double as flow straighteners. One of the things that causes you plane to be so disturbed flying in still air is the wing tip vortex that it produces. I am building a new plane with half a dozen or so thought processes 'outside the box' of stuntisms. One of the things that makes this event fun!
RO