Homemade parachutes

[10fttall]

I want to make a nylon parachute for an upcoming rocket that will weigh in around 3lbs. All the calculators agree I'll need about 50" of parachute. All the sites I've been able to find describe some fancy patterns many multiple sectors.

Is there anything wrong with getting a big honking piece of nylon in a circle or octagon and rigging it up with 6 or 8 lines? Is there really any reason to have a fancy sewed together "quilt" as opposed to upscale the engineering and materials from LPR parachutes?

I see from the calculators that a flatter chute needs to be marginally bigger, but so what? When you're into the realm of pounds, I don't think it's going to make that much difference. And rockets needing that calibur of parachute aren't exactly going to be hurting for space to put a slightly bigger chute.

So, are there any other reasons I shouldn't save myself a ton of work and keep it simple?

 

[Sheri]

I've made numerous homemade chutes. That size sounds right for the size model you are talking about.
The light weight ripstop nylon from your fabric store works great and only costs about $4/ yard for a 60 inch width piece and comes in a lot of colors. There is a nice fold pattern to make the 6 and 8 sided chute where you only make one cut across a few layers of the fabric, it turns out perfect...I believe estes has it on their site, if I find the link Ill post it.....
For the risers, You can sew them on or I have used a hole punch to make a nice round hole, then put on those hole reinforcers that snap onto each side of the fabric. For the edges I fold it over twice and then double stitch around the outer edge on all sides.
My chutes have been burned dragged through cactus, pulled through mesquite trees and come out fine, I save the scraps for any repairs. I reuse these chutes and switch from model to model...

Hope this helps....SHeri

 

[Sheri]

Heres the link, look on page 5 of this document, lower right hand side

clicky

 

[wwattles]

Cheater version: Go to a thrift store or 99-cent store and buy a cheapo umbrella. Carefully remove the metal parts. Tie/sew your shrouds on and you're off to the races. It's not ripstop, it's not fireproof, but hey, it's a good hemispherical chute for very little dough.

(This idea courtesy of Brian Moulton, cheap rocketeer.)

WW

 

[Micromeister]

Hemi chutes catch 3 time the air of flat chutes of the same base diameter. My NCR Brighthawk with Nite flight gear and 5-D cluster mode is a few grams over 3 lbs. It recoverys very nicely on a 36" hemi.
So to answer your original question, Yes there is a very good reason for taking the time to layout Gores that will lead to the fabrication of Hemispherial rip stop chutes...Ya Don't need to make them Quite so BIG

 

[rocketguy101]

I found an interesting paper on the analysis of air flow around parachutes it is here

 

[lessgravity]

You might find this post on my blog useful:
Parachutes

 

[10fttall]

Thanks everybody, this has all been very helpful! I'm going to try that umbrella trick with some slightly smaller chutes. For this big one, I'm going to just cut a 51" octagon out of nylon and sew the edges. The way the components are looking, I might need to add weight to get the flight profile I want for a G80.

 

[Roman]

I use umbrellas as parachutes all the time... a normal one-person umbrella(usually 110cm in diameter) is just right for a 3lbs rocket.

Just add 6 or 8 (depends on the umbrella) lines and your chute is finished.

 

[Stefan_Jones]

For a while, "Dollar Tree" was selling a 21" diameter, red and white nylon kiddie umbrella.

I bought nearly a dozen and turned them into parachutes. The shrouds are braided (not twisted) bright green surveyor's cord.

They work really well. Probably a bit heavier than you'd expect for a parachute of that size, but nice and sturdy.

I have a few other, larger umbrellas waiting for the same treatment.