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Old Dec 20, 2005, 09:39 AM
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Joined Dec 2003
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Curvy surfaces, and blended systems.

I have always liked the X-19 model I had, that was full of curved surfaces, the wings, body and such was almost hard to imagine flying. My question is how would I recreate this in a funtioning model. Not only a curvy shape to the wings foil area, but the drooping wing tips. The Movie "Stealth" had a UCAV with the same ideas, how would I go about trying to make these? I can make a basic wing with curved leading, trailing edges, and tips... but making the wing "Droop" is beyond me at this point. Thank you in advance for any and all help. -James
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Old Dec 20, 2005, 11:04 AM
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Palmdale, CA
Joined Oct 2000
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Figure how much depth the tips will be from the top of the plane, then get a block of foam and carve off everything that isn't X-19.
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Old Dec 23, 2005, 01:10 PM
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United States, TX, Fort Worth
Joined Jun 2000
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What Sparky said.

We have been doing some interesting stuff around here in foam. We are directly CNCing complex foam parts on a CNC machine and/or a CNC router table with some Z axis capability.

One model was a small EDF....did the fuse in two parts and CNCed in the perfect inlet and exhaust ducting shapes....Insert fan, wire it up and go. This made creating complexe inlet duct shapes EASY.

You might also check out "sparks" (Keith Sparks) book on building with foam. Some of his techniques could lead you to the type of shapes you are looking for.

Some have the eye to sculpt a pretty shape out of a foam block, some need a map to get there.
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Old Dec 23, 2005, 01:13 PM
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United States, TX, Fort Worth
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Last edited by Thomas B; Dec 23, 2005 at 01:14 PM. Reason: duplicate post...sorry
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Old Dec 25, 2005, 11:14 PM
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Colorado Springs, CO
Joined Oct 2004
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I've had to tackle the "curvy surface" problem in a completely different genre--1930's racers. (The most drop-dead gorgeous planes of all time, IMHO, but that's a discussion for another forum. ) I stack 1/8" balsa pieces of the appropriate cross section, CA them all together, then get out the sanding block.

It's labor-intensive, but the results are worthwhile, and the thing about stacking the sheets is that you get contour lines at the seams that help you make sure that the shape is right and, in the case of a cowl or something, symmetrical.

Good luck!
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Old Dec 26, 2005, 08:10 AM
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East Anglia, UK
Joined Sep 2002
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yup

The way the original aircraft were done was to build skeletons, and cover them with curved bits of plywood, or in the case of later aircraft, sheet them with curved bits of alloy.

It's doable today with things like ultra thin ply, balsa or depron.

Ultimately bits of abrasive paper, filler and 'bionic eyeballs' make it all come out right..enough....
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Old Dec 26, 2005, 02:34 PM
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Like that. That was a template cut from cardboard. When I liked the shapes, I traced them onto paper. To get the full figure , I made 2 of everything. The skeleton was then filled with foam and bondo to make a plug. Basically, think like a shipwright and study the forms and shape transitions in playboy.

Here is a look at the mold making in progress:

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Last edited by ElectroStorch; Dec 26, 2005 at 02:47 PM.
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