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Speed,Combat,Scale,Racing => Rat Racing and Team Racing => Topic started by: Dwayne on March 19, 2017, 07:26:17 PM
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The Balsa Beavers Club in Toronto are starting a new event, LA 15 sport scale racing using either a Sig Buster or Shoestring, sounds like fun so I'm going to give it a go, I've chosen the Shoestring. There will be 2 prelims off 100 laps with two pit stops and the final will be 200 laps and 4 pit stops. I'm going to need a shutoff and from what I've been told the one from Brodak would be to big and heavy for a 15, anyone have one for a 15 size plane?
Thanks
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A piece of music wire and a 1/2 A control horn. Light, simple, bullet proof. H^^
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Right. Easy enough to make one. The Brodak unit wasn't all the reliable from what I saw. Just about anybody can make a contraption with piano wire, wheel collars and a compression spring.
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A piece of music wire and a 1/2 A control horn. Light, simple, bullet proof. H^^
So you make a spring doohickey from piano wire and then connect a wire to the pushrod at the bellcrank? So when you give full up it pulls the doohickey out of the 1/2a horn and pinches the fuel line. Genius. y1 H^^
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No, you pull full down.
MM
Right, down, please where did you hook up the trip wire?
Thanks
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shut off on the up line is an accident looking for a place to happen, flew a Barten B tr and as hard as I tried I continuously hit the shut off on take off. not fun
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if u have your control horn on to of the elav u can attatch shut off wire to the push rod ,or add another small control horn to the elav
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Here's the one I was looking for. Simple, reliable. About an hour's work.
The only thing a little tricky is grinding a square-edge notch in the plunger wire. You need to cut the plunger about half way through to give the trigger enough bite.
Also, be sure to have the control horn on top. That way the pushrod will buckle a little and not have the nose move much when you trigger it.
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Here's a picture showing the installation. If you build your Shoestring with the bellcrank on the inboard side (per the plans) just install a control horn on the top side of the outboard elevator, and run a cable to the shutoff. Small cotter pins stuck into the fuselage make good cable guides as required.
I recommend you check out my Sportsman Goodyear construction article "Margaret June" on modelaircraft.org. For space reasons, only the introductory paragraphs made it into the print magazine, but the entire construction article is available on line. You might be able to get some ideas.
Bill Bischoff
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Thank you so much for all the help, I'll be sure to post pics when i build it, I ordered the kit through my LHS should be here next week.
y1 H^^ ;D ; ~> #^
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I've used the 1/16th music wire and 1/2 A control horn for 3 of my Sportsman Goodyear racers like Bill is showing in his plans. They are very effective and easy to make and easy to adjust.
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True.
And the reset procedure of a simple shutoff may not be optimum in a race.
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They say you can never make something foolproof... Anyway, we've had no problems or incidents locally. I suppose it's all a matter of what you're used to.
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Dwayne, Make sure you put a little shape on the bottom of the wing if not almost symmetrical. The Shoe has a big wing and you don't need all that lift. Flat bottom wing Shoestrings fly nose down and they hunt.
Hope that helps,
MM
Thank you for this, the Shoestring wing comes flat and needs to be shaped and the plans show a flat bottom as you state so I sent a e-mail off to our club pres and asked for a clarification, can we shape a symmetrical wing and received a reply that after much debate the rules will be changed to allow what ever shape we want as long as the size of the wing remains stock and we can't change the thickness.
Thank you again this is a new event for us so there will be much tweaking involved.
H^^ y1
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For your next club build consider Bill's Boo-Ray design. Use the details off his Margaret June plans. Not any harder to build than the Sig kits as it uses the pre-shaped wing from the Brodak Flite-Streak Trainer (ordered separately). Mine is close to being finished, fun project. ;D
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In our part of the country if you start flipping the prop before the go signal means a no start/go signal or you have to shut down and restart.
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I won a lot of races with these. 8)
Al