Chutes...what sizes?

[phaar]

My bro, friend, and I went to a fabric store after school yesterday and bought some nylon (rip-stop, I think, gotta look at it again) for some chutes we can make to sell at Underdog Rockets. We also bought some nylon material cord for the shroud lines. I need to know what size chutes would be most popular. I know probably a 24 and an 18. What do you guys think? Any shapes besides circular we should consider? Any tips on making chutes?

 

[Justin Horne]

Maybe even a 30 or 36 for the bigger ones...
As for tips, all I can say is make them strong... Shrouds up >3 inches, strong lines, strong attatchment points, etc. You probably 'could' make hemispherical chutes, but it probably wouldn't be cost effective with all the time.

 

[GL-P]

a) try a 36 inch chute when you get good

b) don't tie knots in the shroudline where it meets the canopy because it adds to the bulk

c) Try hemisphericals. That make nicer shapes and are more efficient when inflated.

Good luck. Post pics!!!

 

[lalligood]

There's a resonably good looking tutorial on building parachutes for rockets here: https://www.vatsaas.org/rtv/systems/Parachutes/Chute.aspx

You also don't want to cut rip-stop nylon with scissors because it frays badly. There are parachute vendors online (the URLs escape me right now) that sell "heat cutters" (total brain f@rt now) that allows you to "melt" a clean seam in the fabric... They run about $20.

HTH,

 

[GL-P]

I wish I knew that!

I remember now, try https://www.nakka-rocketry.net/xchute1.html and https://members.aol.com/ricnakk/paracon.html

The gore pattern on his chutes are nice. I only do 8 or less panels.

 

[phaar]

I saw in the other thread with those parachute guys at target. Do you think that could actually work on a bigger chute. I mean I know it would add quite a bit to the weight, but if it was between losing a rocket in a tree or not going as high then I would definately choose the first. What is everyone's opinion. Would you buy one?

 

[edwardw]

I have tried the mesh shroud line on a couple of my parachutes. Needless to say it adds up quickly in weight and bulk. It's hard to beat the weight of 3 continiuos shroud lines that weigh 20 grams vs a heavy mesh. Also, I found it a little frustrating making the fabric into a cone of the right size for the parachute. It took a couple trial and error sessions with a lot of pins before I got something that had the right depth and width when deployed. It was a fun experience, but I won't be doing it on any of my other parachutes.

As for tips - make sure you have a sewing machine that runs nice and smooth - ripstop is slick and sometimes bunches if your presser foot doesn't grab it. Rotary cutters are great also, but watch the fingers - they get cut really easily. Also, dont try to use too heavy a thread for your needle - it will bunch up and be a pain. Just some things I found useful when starting making mine.

Edward

 

[DynaSoar]

Originally posted by phaar
My bro, friend, and I went to a fabric store after school yesterday and bought some nylon (rip-stop, I think, gotta look at it again) for some chutes we can make to sell at Underdog Rockets. We also bought some nylon material cord for the shroud lines. I need to know what size chutes would be most popular. I know probably a 24 and an 18. What do you guys think? Any shapes besides circular we should consider? Any tips on making chutes?

X-form chutes. Less drift. I think they fold much nicer and easier too. Draw an octagon, and cut out the diagonals to right angles pointing in. Make one, and a regular chute, and compare. Keep in mind an X-chute will only have 78% the area of an octagon of the same side length.

 

[rocketsonly]

Originally posted by DynaSoar
X-form chutes. Less drift. I think they fold much nicer and easier too. Draw an octagon, and cut out the diagonals to right angles pointing in. Make one, and a regular chute, and compare. Keep in mind an X-chute will only have 78% the area of an octagon of the same side length.

You can compare descent rates between different types of parachutes here:
https://www.rocketreviews.com/tool_descent_rate.shtml