Gore pattern help

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AtomicStorm

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Just wondering if anyone had a Gore pattern they could lend me for an elliptical parachute. Let me know what you have, im looking to make a 18"-36"
 

AtomicStorm

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AtomicStorm

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Ok so im a little stumped here. I printed off the pattern and the seem allowance is exactly 1" and that is correct but the length of the gore is 14.5". Which i think is wrong. It suposed to be a 32" chute with a 20" dia. Spillhole, so shouldn't the gore only be 6" and not 14.5"??
 

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Handeman

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You have to define your terms. It seems every manufacture has a different way to measure chute diameter.

If you are making a 32" inflated diameter chute and it's an elliptical design, I would expect the gore to be about 20 to 22 long, depending on diameter of the spill hole.

With 32" diameter, the distance up and over the top and back down the other side should be about 40 to 44 inches. A 32" diameter spherical chute would have a side to side distance across the top of the chute of 1/2 * pi * 2* r . or half the circumference of the sphere (pi * r) or about 50".

If your definition of diameter is the distance from side to side of the chute material when laid flat, which is used sometimes, then 14.5" would be about right, but the inflated diameter would probably be less then 32".

The same holds true for flat chutes. Some manufactures define diameter as the distance when laid flat from one straight edge to the other. Other manufactures use the point to point distance as the diameter.

The bottom line is, saying a 32" diameter chute doesn't mean much. It could be completely different sizes, Cd, and decent rates, depending on the manufacture's or designers definition of diameter and the shape or manufacturing method used to make the chute.

In your case, a 32" diameter elliptical with a 20" diameter spill hole, 14.5, minus 2" seam allowance (1" per end) leaves about 12.5" of mostly vertical chute material that curves upward toward the spill hole. That sounds about right to me.
 

AtomicStorm

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So it took me having to make them too small to relize that instead of making a 2d circle im making a 3d half sphere where the diameter is 32" . I realized the gores are alot longer then the diameter and now i understand why they work so well. Its because theres so much surface area in a small space. Chute, im starting to unterstand everything now. 🧐
 

AtomicStorm

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I got my gore patterns done and have cut out the 4 orange gores, tomorrow i will trace and cut out the 4 black ones. Waiting for the shroud lines and seam tape to come in the mail.
 
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