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Building Tips and technical articles. => 1/2 A building. => Topic started by: Mark Mc on September 25, 2020, 09:44:01 AM
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I was just reading the Gremlin 1/2A pattern plane article in the May ’75 issue of Model Builder by Tom Dixon, and it says the plane flies on a Cox “stunt special” engine. The “stunt special” is a TD .049 with a Babe Bee piston/cylinder and a low compression glow head, a Kirn-Kraft NVA, and turning a Cox 6x4 prop on 5% nitro fuel from a Perfect wedge tank. Tom says this pulls the 12 ounce model through the entire stunt pattern. The KK fine needle would be the only thing I would have associated with “performance”. A low compression head topping a single bypass/no boost cylinder with SPI doesn’t scream “performance”. 5% nitro on a 1/2A doesn’t scream “performance”. A TD on suction from a standard plumbed wedge tank doesn’t scream performance. And a Cox 6x4 doesn’t scream “performance” (unless you’re propping for torque). And we all know Cox TD engines were made to scream.
What exactly am I missing on this?
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Sound all wrong to me! I went the other way with a Medallion bottom end and Tee Dee top. 15% Nitro. Great runs!
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Sound all wrong to me! I went the other way with a Medallion bottom end and Tee Dee top. 15% Nitro. Great runs!
This is what I’d do.
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Oh, why did I see this? This plane is cute. Now I want to build one! For all the concern about tail weight, I wonder how it would be scaled up about 5-8%, and flying a Norvel Big Mig .061.
Thanks for the tease.
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Go with it as is and just fly on longer lines. You’l love it.
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Sound all wrong to me! I went the other way with a Medallion bottom end and Tee Dee top. 15% Nitro. Great runs!
Indeed, your method sounds a lot more plausible, the last things you want is to lower the compression or run the TD intake system
Brett
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Nothing wrong with the Tee Dee in take system, it is the wild Tee Dee crank timing! A Tee Dee with a Medallion crank shoUld run just fine as a stunt engine, it is just easier to grab the entire Medallion bottom end. (Especially if you work in the factory 🤭)