Make a parachute

[Rocketbegg]

B.F.R.A

Stands for "Bruce Family Rocketry adventures". There isn't a whole lot of stuff on there as yet, but I keep adding videos here and there. When I'm done with my current projects, I'll make a parachute tutorial.

https://www.youtube.com/channel/UC2OjQvVKT3iNx0-Tj4dZY0w?view_as=subscriber

OK! best wishes in your project!

 

[Rocketbegg]

As @ep29030 said, there are several things to consider when deciding upon an ideal parachute design. Personally, my rocket fleet is mostly a mix of hexagonal chutes cut from heavy duty trash bags or multi-gore ripstop nylon elliptical parachutes (I usually go for 20 gores because I like that look, see below)

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When you say 100cm diameter, that's a bit bigger than a lot of parachutes for mid power rockets. How much do you expect your final rocket to weigh? Also, have you determined the exact dimensions of each gore yet? If so, stitching them together is pretty easy. The method I use is to lay one gore on top of another with a thin strip of newspaper underneath. The paper is there to allow the sewing machine to actually grip the fabric and move it along since ripstop nylon can be a bit too slippery against the metal parts.

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From there I stitch the edge, tie the ends, cut off the excess thread and rip the paper out. Then I move on to the next gore.

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Once all the gores are in place and the canopy is complete, I attach my shroud lines (I like to use 0.5mm nylon) by stitching it in place BACKWARDS (going from the edge toward the inside) for one inch, turning it around and then stitching it back down so there are two inches worth of anchored shroud line at every point. Each shroud line is made twice as long as necessary so for a 20 gore parachute, I end up with 10 loops. I finish off with a metal S-hook holding the whole bundle and a piece of heat shrink to keep them from slipping around.

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This is just my way of doing it, but there are lots of little tweaks and variations out there. I hope this gives you some ideas on where to go with your project. Keep us posted on your progress!

I like sewing my parachutes too; personally like the strength and finished look of the French feld seems... I use zero porosity 1.1oz nylon from paragear.com.

I make them hemispherical scottbryce.com is sooo helpful [emoji4].

Use the tip of a wire wrapped around my soldering iron to cut the fabric and ironing the seems before pinning makes it easier to form the feld.

My machine only straight stitches so I sew them twice. Hem the bottom of the skirt, lay a binding tape made from bias cut fabric around the spill hole.

Some pics as example

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They’re definitely a test of my patience and take some time - estimate 6 hours or so.

Blue skies,

Craig

So much thanks!!! Your chute is AWSOME!!! Great JOB!

 

[SRB]

I was wondering if anyone had any suggestions on how to calculate a Cd for a parachute. My team is trying to build the drogue and main for our high power rocket. The rocket will be around 96lb and be going 10k. The Cd we where hoping to achieve is more then .98 so hopefully something around 1-2.2 I know that is high but if anyone has any suggestions on resources I would really appreciate it! Thank you!

 

[SolarYellow]

Lots and lots of posts here. Search button is your friend. It may be more efficient to use Google to search the site.

I guarantee you nobody who could point you to a particular thread is going to be able to find what they point you to without using the same search you'd use to find it.

 

[Handeman]

I was wondering if anyone had any suggestions on how to calculate a Cd for a parachute. My team is trying to build the drogue and main for our high power rocket. The rocket will be around 96lb and be going 10k. The Cd we where hoping to achieve is more then .98 so hopefully something around 1-2.2 I know that is high but if anyone has any suggestions on resources I would really appreciate it! Thank you!

I suggest you download and go through the Parachute Recovery Systems Design Manual from the Defense Technical Information Center. It's old, but there aren't many questions about parachutes that can't be answered by reading that.

 

[sriegel]

I was wondering if anyone had any suggestions on how to calculate a Cd for a parachute. My team is trying to build the drogue and main for our high power rocket. The rocket will be around 96lb and be going 10k. The Cd we where hoping to achieve is more then .98 so hopefully something around 1-2.2 I know that is high but if anyone has any suggestions on resources I would really appreciate it! Thank you!

A hemispherical or elliptical chute will both come in at 1.5 for Cd if you use the open area at the skirt as your reference area. A flat sheet is 0.75 based on the area of the sheet.

Shoot me a message if you would like some help on the math for weight, chute size, Cd, and descent rate.

Steve