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General control line discussion => Open Forum => Topic started by: Bootlegger on February 20, 2020, 09:03:15 AM
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Guy's I am thinking about reducing the Sig Twister by 25% from 48" to 36" to build a 1/2 A stunter, am I going in the right direction, and should I reduce everything the same percentage? Sure can use some help/advice and Thanks...
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I'd be cautious, changing a model's wing loading and length may not hold the same relationship. I did the same to a Tutor and was unhappy with the way it handled.
Steve
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I did exactly this to an Al Rabe 'Mustunt 1' - 48" down to 36", with an OS Max .15 for power. It was too heavy at 25 oz., but flew very well - so well, in fact, that I wore the old OS out with hundreds of flights. A word of advice: nothing with less power than one of the older glow .15s would have flown it successfully, even if I'd managed to build it to the planned weight of 22 oz.
Regards
John
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Shrinking it down to 36" basically puts it at the same size as the Akromaster, which is already a scaled down Twister (with a few minor differences), so why not just simply start there. SIG has the kits for $31.97 (extra for shipping). Really hard deal to beat.
Akromaster - $31.97
https://sigmfg.com/collections/control-line-kits/products/sig-akromaster-kit (https://sigmfg.com/collections/control-line-kits/products/sig-akromaster-kit)
(https://cdn.shopify.com/s/files/1/2281/6393/products/yy1SIGCL20New.jpg?v=1505085384)
VS
Twister kit - $61.71
https://sigmfg.com/collections/control-line-kits/products/sig-twister-kit (https://sigmfg.com/collections/control-line-kits/products/sig-twister-kit)
(https://cdn.shopify.com/s/files/1/2281/6393/products/yy1SIGCL22New.jpg?v=1505085522)
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Here's what my 36" Mustunt 1 looked like at its best - the changes I made were purely cosmetic, keeping tail unit areas the same. To save weight,the wing wasn't fully sheeted, but it was still much too heavy!
John
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Go for it, with all due attention paid to what's been said. If I did it I wouldn't expect to hit the ball out of the park on the first try -- usually my original designs are incremental changes from something that works, or if they're totally "fresh off the board" then I end up making a second or third revision.
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If I'm doing an "original" I also shamelessly copy details from other people. Heman Lee's very nice "Half-lite" stunter has a 31" wingspan and flies on a Norvel 049 or 061. I'm not sure whether or not a TD 049 could pull it (I don't know how they compare to Norvel 049s), but I'm sure a Medallion or a reedie couldn't pull it (unless you got the reedie from Paul Gibault -- then all bets are off). It's not just the size that matters -- different motors are going to have wildly different performance levels, here.
There's a half-a Shark that works well on the TD 049; you could hunt down those plans and use them as a guideline.
https://www.scribd.com/doc/24029397/Building-a-1-2a-Control-Line-Stunter
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Guy's I am thinking about reducing the Sig Twister by 25% from 48" to 36" to build a 1/2 A stunter, am I going in the right direction, and should I reduce everything the same percentage? Sure can use some help/advice and Thanks...
At 75% size, the Twister comes out at about 287 square inches, while the Akromaster is listed at 250 square inches.
Just for fun, here are comparative wing areas for some 1/2-A models:
Sig/Berkeley Mini-Zilch 95
Southwestern 1/2-A Snapper from the ‘50s 107
Consolidated Wowee from the ‘50s 150
Larry Renger Skyfire (profile, Cox foam wings) 165
Hunt Envoy (full fuselage) 210
Dick Mathis Pinto (full fuselage) 220
Cal Shumate Blackhawk (full fuselage, 2 Cox TeeDee .049s) 230
Keith Trostle Tercel (full fuselage) 246
Dennis
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I did a 60% Twister wing a few years ago. It was a exact copy of the wing down to the flaps. The wing span is right around 31". The fuse is the same numbers as the 1/2 a light that was talked about earlier. I built this in a rush to try it and it flies great. It will do the entire pattern with ease and do it slowly. It has a Norvel 061, APC 6x2 prop, and flies on 10 lb Power Pro lines at 42' if I remember right. I have done a few contests with this in advanced and have done well with it. I am planning on doing another with lighter wood and take a little more time on it I am not changing anything on the next one.
Rick
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And another
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What seems like a million years ago when I built the TwistMaster (Twister made to look like a Ringmaster) I, with a little help drew a complete set of plans in AutoCAD for the Twister showing the changes I made to resemble a Ringmaster. I still have the CAD file which could be scaled to whatever size one desires. If you would like to have the CAD file send me a PM with your email address and I will send it to you.