Parachute patterns

The Rocketry Forum

Help Support The Rocketry Forum:

slohand

Well-Known Member
Joined
Dec 2, 2018
Messages
68
Reaction score
37
image.jpeg
image.jpeg
image.jpeg
Okay, first thing is, no funny stuff but I like sewing ..... Now that that is out of the way I've been looking for some good parachute patterns. I've made Richard Nakkas parachutes, and they are beautiful but man do they ever take up a lot of space. I'd really like to make something with less shroud lines. I've seen the simple eight line square panel designs but there's got to be more options and I just can't seem to find simple patterns.

Any help would be appreciated. Above is one of my Nakka 100 cm chutes.
 

Attachments

JohnCoker

Well-Known Member
Joined
Apr 13, 2013
Messages
1,674
Reaction score
315
X-form parachutes are common. They have only four shroud lines so they tangle less and are easier to pack.
 

boatgeek

Well-Known Member
Joined
Dec 27, 2014
Messages
2,585
Reaction score
1,018
I tend to make 6- and 8-gore semi-elliptical chutes with a spill hole. I don't really see more gores being really helpful. I'll try to get PDF patterns for these two (30" 6-gore, 36" 8-gore) up in the next couple of days. I make the patterns in Rhino and then plot them out and cut out the patterns.
IMG_1901.JPG IMG_1871.JPG

The 8-gore one was the first one I've used French fell seams on. I like that approach, but it was a bit more work.
 

slohand

Well-Known Member
Joined
Dec 2, 2018
Messages
68
Reaction score
37
X-form parachutes are common. They have only four shroud lines so they tangle less and are easier to pack.
Thanks John, is there an online calculator for sizes for payloads for these shapes?
 

slohand

Well-Known Member
Joined
Dec 2, 2018
Messages
68
Reaction score
37
Thanks all for your input. I'm going to try an 8 gore next. In the meantime I made this xform. Each panel is 35mm square. From the research you folks have guided me to this should be plenty of surface area for a soft landing of a 650 gram rocket. Has lots of good reinforcement too.
20190327_074203.jpg

20190327_074138.jpg
 

Tobor

Get your peanuts....
TRF Supporter
Joined
Oct 8, 2016
Messages
1,582
Reaction score
332
Nice work there.
 

slohand

Well-Known Member
Joined
Dec 2, 2018
Messages
68
Reaction score
37
Thanks Tobor, my wife is a quilter so I have a good coach
 

Thundercloud

Well-Known Member
Joined
Jul 7, 2017
Messages
159
Reaction score
12
I never got the hang of how to design for, and sew, a French Felled seam. How much extra material do you leave on each side?
 

Thundercloud

Well-Known Member
Joined
Jul 7, 2017
Messages
159
Reaction score
12
That was a good video, and other good videos followed. I learned that there is a French felled seam and a flat felled seam (but probably no such thing as a French Felled seam). I think the goal for parachutes is the strongest seam with the least amount of fabric or "allowance." From my extensive 10 minutes of video training, I am guessing the flat felled seam would be the winner for both the least fabric and most strength.
 
Joined
Mar 3, 2019
Messages
24
Reaction score
16
That was a good video, and other good videos followed. I learned that there is a French felled seam and a flat felled seam (but probably no such thing as a French Felled seam). I think the goal for parachutes is the strongest seam with the least amount of fabric or "allowance." From my extensive 10 minutes of video training, I am guessing the flat felled seam would be the winner for both the least fabric and most strength.
The French fell has proven to be the most efficient parachute seam for radials. Both seams can use the same amount of allowance for the seams. It is really up to you on how much allowance you put in. A true french fell uses 2 loaded stitch rows where a flat fell only uses one. There are videos on how to do a true french fell for parachutes on youtube, might take a little searching but you can find them.
 

Thundercloud

Well-Known Member
Joined
Jul 7, 2017
Messages
159
Reaction score
12
Thanks, that is good to know. When I was working on large rear ejection rockets, I was trying to make chutes that would pack small but be very strong. The radial seams gave me trouble. I had a woman that sewed wedding dresses do the actual sewing. I had left unequal allowance on the mating pieces, which was incorrect and confused her. She ended up making many passes over the seam (because I told her I needed it really strong) which caused enough puckering to shorten the seams significantly and change the final shape.
 

Banzai88

Lvl 1,Wallet....Destroyed
Joined
Jul 15, 2015
Messages
1,964
Reaction score
246
I've used flat/french seams, takes some getting used to designing seam allowances for, but once you get it, it's second nature. Lately everything I've been doing has been simple serged seams. $100 wal mart serger works just fine. I have YET to have a failure of any type of stitching.

In every off optimal deployment that I've ever seen, seen the aftermath of, or personally endured, it's ALWAYS results in a failure of the fabric way before even stressing any of the stitching. That includes shroud line attachment points. And when I say off optimal, I mean something as catastrophic as no apogee deployment, followed by a ballistic trajectory, followed by a planned main deployment at full speed!!! Ouch!
 

Thundercloud

Well-Known Member
Joined
Jul 7, 2017
Messages
159
Reaction score
12
As far as patterns go, the X-form is about the easiest, as you have discovered. It is also very strong and very stable. It can in theory tangle and/or spin, but I have had excellent luck with them, especially for drogues. I haven't had the need to make my own main chute in quite a while, but if I did, I would try a disc-gap-band chute like they used on some Mars missions. It looks like a very simple but good design.
 

Thundercloud

Well-Known Member
Joined
Jul 7, 2017
Messages
159
Reaction score
12
As far as Sergers go, I never heard of such a thing! If it makes sewing seams and finishing edges easy, then I'll keep that in mind for my next project.
 

JERRYR708

Well-Known Member
TRF Supporter
Joined
Apr 29, 2015
Messages
575
Reaction score
45
Location
Apple Valley, Ca
Awesome job on the parachute! I learned to sew to make a sail on a medieval model ship I built. A man just needs the right incentive and he can sew...:) Now my wife has me sewing curtains with rolls of fabric from HL..:-(
 
Joined
Mar 3, 2019
Messages
24
Reaction score
16
As far as patterns go, the X-form is about the easiest, as you have discovered. It is also very strong and very stable. It can in theory tangle and/or spin, but I have had excellent luck with them, especially for drogues. I haven't had the need to make my own main chute in quite a while, but if I did, I would try a disc-gap-band chute like they used on some Mars missions. It looks like a very simple but good design.
If you need a spreadsheet for the Viking DGB ratios, let me know. Very simple to make.
 

Chris_H

Well-Known Member
Joined
Sep 13, 2017
Messages
476
Reaction score
71
I think a serger is not a good idea for ripstop. If the edges are heat cut, then the seam might hold up better.

I use a felled seam, not sure if it is French or not, but it is the standard seam for ripstop.
 

Chris_H

Well-Known Member
Joined
Sep 13, 2017
Messages
476
Reaction score
71
A serged seam in ripstop will last a while, but it will fail long before a felled seam. Heat cut edges help add longevity, also.

I have a serger, and would not think of using it for parachute seams.
 

Banzai88

Lvl 1,Wallet....Destroyed
Joined
Jul 15, 2015
Messages
1,964
Reaction score
246
5 years now, not 1 failure of a seam. Try it before you discount it out of hand.
 

AfterBurners

Well-Known Member
Joined
May 8, 2012
Messages
7,432
Reaction score
316
Location
Dallas Texas
If any you decide to make flat hex shaped parachutes, take the time and sew the shroud lines across from each other. Doing so will keep the lines from tangling. Every flat hex chute I've seen always has their lines crossed.
 

JonathanOtt

Well-Known Member
Joined
Jun 13, 2015
Messages
307
Reaction score
54
Location
Fayetteville, NC
2
Top