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Author Topic: Hi start advice  (Read 143 times)
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billdennis747
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« on: January 05, 2020, 05:14:58 PM »

Hi, can anyone help a friend of mine who is building a KK Chief 60" vintage glider for RC. What kind of home-made hi-start would work, or is a commercial one better? Nothing too powerful
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NormF
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« Reply #1 on: January 05, 2020, 06:03:00 PM »

Hi-starts are pretty simple and for a 60” converted FF?, you could use, say 25’ of 1/4” rubber and 50’ of 10# braided fish line. Use a metal ring and a piece of silk or plastic as drag. For more zip, and an idea of the basic components, see: http://www.dynaflite.com/accys/gpmp8015.html
If the plane is of FF construction (balsa spars) go easy on the tension. Also make sure the towhook is forward of the wing CG, 20 degree angle is very safe and launch with basically an assisted hang glide. If OK, you can add more tension and move the hook back.

Norm
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DavidOWade
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« Reply #2 on: January 05, 2020, 08:41:16 PM »

FWIW, recently I have been playing with hi-start for free flight. My model is a 60" span F1H style plane (227 sqin of flying surfaces like an old A-1, but heavier). It weighs 230 or so grams. I am using 25 grams of single strand 3/32" rubber (about 25') and 150 feet of 10# braided fishing line. Others, flying lighter planes of similar wing area, are successful with a single strand of of 1/16" rubber. A bulkier plane that is harder to push through the air may require thicker rubber that we are using. We are stretching the rubber to six or seven times its original length. Start slow and work your way up. David
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Re: Hi start advice
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billdennis747
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« Reply #3 on: January 06, 2020, 03:15:35 AM »

Thanks both - I'll pass it on.
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lincoln
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« Reply #4 on: January 06, 2020, 05:25:41 PM »

You may be able to find some very small latex tubing, which might be more durable than model airplane,rubber. But I bet it costs more, too, and I don't know how whether the appropriate cross sectional area is the same. i've had good luck with black latex tubing, and,with some natural colored latex. Other natural colored latex turned to gummi worms in short order.
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