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Building Tips and technical articles. => 1/2 A building. => Topic started by: Larry Renger on November 02, 2008, 07:30:12 PM
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Here are photos of my recently completed Skyfire. It weighs 7 ounces. Power is a Tee Dee .049 running side port pressure, a Norvel plug and Kirn-Kraft needle system. Prop is an APC 6x2. Tank is 1 ounce. Wing area is 165 sq.in. The Cox folded foam wings have an added internal spar that punches the thickness up just a tad and keeps it there (they tend to collapse over time otherwise). It has a 3" bellcrank, and I use the RSM Ultimate handle to smooth out the level flight and round maneuvers.
I fly it currently on 42.5' .008 cable lines, and may try 45'. It is rock solid everywhere in the pattern, and a couple of expert fliers are interested in building one. I may draw up the plans with a built up wing, as the Cox wings are getting rare. Of course if one of you cottage-industry dudes learned how to mold Depron.....
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Larry,
Very nice! H^^
Bill
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Larry , very nice work!! I would like to do something similar this winter with a Hyper-Viper wing. Not familiar with the t-nut you had mentioned for the pressure nipple or the Kirn-Kraft needle assembly. I have a tee dee .049 that i would like to use on this project. Any info on the t-nut and needle would be appreciated. Ray
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Larry , very nice work!! I would like to do something similar this winter with a Hyper-Viper wing. Not familiar with the t-nut you had mentioned for the pressure nipple or the Kirn-Kraft needle assembly. I have a tee dee .049 that i would like to use on this project. Any info on the t-nut and needle would be appreciated. Ray
Ray - maybe you call it a "blind nut". A t-nut is the standard motor-mounting blind nut. I think that
(judging from the picture), the outer diameter is ground down into a "lip" that the pressure tubing will
not slip off of and then the nut is just screwed right onto the plastic nipple.
A kirn-kraft needle assembly is a fine-thread (128 thread/inch) needle valve that replaces the Cox
needle, which is usually too course a thread when trying to run pressure. Don't know WHERE you might
still be able to get a Kirn-Kraft needle - Ace RC used to have a similar unit, also.
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Right answers, Mike. Good show! y1
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You can get the fine thread needle assemblies from Texas Timers. I got a couple from there and they look like the KK ones I already had from my free flight days.
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Great tip! Thanks, I would like a couple more of them!!! y1
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Hi Larry,
Try http://www.texastimers.com/
The link to needle valves is on the left hand side under Accessories.
They also have needle valve assys that may be useful in other small engines.
Later,
Stan
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Thanks, Stan! I have put in an order.