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- Jan 27, 2009
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I was doing some cleaning and found some spare 2.6" tubing and a nose cone. I did some number crunching/simulations, took a spare wing from one of my Hypersonic kits and made an approximation of a Jayhawk. Wing area is not scale of course so that it would have a hope of rc gliding. I played with the simulations of length and CG/wing location and wingtip sizes to make sure my lateral stability was ok.
I used some styrene sheet and made some small non-scale canards slotted into the nose cone, enough to look the part but not so big to impact my CG location much. I added a laminated depron foam conduit strip on the bottom for mounting some landing skids and rail buttons, and that helped get the body off the ground further to allow an almost symmetric wing tip design. It still isn't symmetric becuase the lower tips would drag on the ground if it were, but it is all painted and waiting for some stickershock vinyl. No nose weight needed, 20" wingspan, 36" long, 11.25oz rtf.
If I had had an uncut 28" length of bt-80 I could have saved 5/8 oz of coupler weight, since the coupler is only about 6" ahead of the cg I have to add back about 1/8 to 1/4 ounce of weight back into the tip of the nose to keep the cg, so maybe would save 1/2 ounce total to the rtf weight. The 2.6" tubing is pretty ideal because it is very light and the nose cone that sirrius carries weighs only 1 5/8 oz. Tube/cone weight is 4.25 oz. If I switched to 3" tubing it would be closer to 6-7 ounces, if I went with bt-101 the tubing would be 3.5 ounces but the lightest nose cone 4" is way too heavy.
Frank
I used some styrene sheet and made some small non-scale canards slotted into the nose cone, enough to look the part but not so big to impact my CG location much. I added a laminated depron foam conduit strip on the bottom for mounting some landing skids and rail buttons, and that helped get the body off the ground further to allow an almost symmetric wing tip design. It still isn't symmetric becuase the lower tips would drag on the ground if it were, but it is all painted and waiting for some stickershock vinyl. No nose weight needed, 20" wingspan, 36" long, 11.25oz rtf.
If I had had an uncut 28" length of bt-80 I could have saved 5/8 oz of coupler weight, since the coupler is only about 6" ahead of the cg I have to add back about 1/8 to 1/4 ounce of weight back into the tip of the nose to keep the cg, so maybe would save 1/2 ounce total to the rtf weight. The 2.6" tubing is pretty ideal because it is very light and the nose cone that sirrius carries weighs only 1 5/8 oz. Tube/cone weight is 4.25 oz. If I switched to 3" tubing it would be closer to 6-7 ounces, if I went with bt-101 the tubing would be 3.5 ounces but the lightest nose cone 4" is way too heavy.
Frank
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