Parachute patterns

[Handeman]

I think that's a large part of my problem. The bottom edge of corrugated cardboard actually sticks out slightly, and the hot knife is welding the nylon to that edge.

I think the other issue is that unlike the hard board, the cardboard has fibers that stick out and end up inside the melted nylon and you actually have to break the fibers to get the nylon off. With the hardboard, it might stick, but it is just surface contact.

 

[Dane Ronnow]

I would sand the edges to have a small radius

Using your idea, I beveled the edge of the cardboard with an X-Acto knife, then wrapped it in a 1-inch strip of aluminum foil, and it works great. The bevel moves the bottom edge of the cardboard almost an eighth of an inch away from the hot knife cut, and the foil keeps the edge from burning, so I can cut a little slower.

Anyway, your idea saved hot-knife cutting of gores for me. Thanks!

 

[Dane Ronnow]

the cardboard has fibers that stick out and end up inside the melted nylon and you actually have to break the fibers to get the nylon off.

Exactly. See my solution above. Works great.

 

[Greg Furtman]

Using your idea, I beveled the edge of the cardboard with an X-Acto knife, then wrapped it in a 1-inch strip of aluminum foil, and it works great. The bevel moves the bottom edge of the cardboard almost an eighth of an inch away from the hot knife cut, and the foil keeps the edge from burning, so I can cut a little slower.

Anyway, your idea saved hot-knife cutting of gores for me. Thanks!

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You could probably also the aluminum tape they use to seal ductwork joints.

 

[Blast it Tom!]

You could probably also the aluminum tape they use to seal ductwork joints.

Absolutely. I save my aluminum foil strictly for making hats!

 

[icyclops]

Hey, me too!

 

[Yukon@K-9 Rocket Tech]

I notice you use a loom or line separator on that design. I'd thought of that as well, though for low power it might be a bit of overkill.

I tend to over engineer

 

[camilacunha]

Hello, excuse the old thread ressurection but wondered if you all might be interested in this online design tool for annular parachutes that we've just put online.. image is of the first one we made using these calculations based on the T. W. Knacke book maths. https://www.openresearchrocketry.co.uk/projects/annular-parachute-calculator
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Hey, I'm from Brazil and I can't have access to the calculator. Is the link down or restricted for my country?

 

[Greg Furtman]

Hey, I'm from Brazil and I can't have access to the calculator. Is the link down or restricted for my country?

It doesn't work for me either.

 

[boomtube-mk2]

Parachutes? Only Whimps use parachutes.

 

[sriegel]

Here's a cool design, and it's now on Mars!
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I could not do 80 gores but this is my version in 36. 8' polyconic. Codes the same in 5-bit binary.