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  #11  
Old 06-07-2020, 08:41 PM
RobVG RobVG is offline
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New parachute under construction.

I'll probably sound like one of those new guys who thinks they're an expert but I'm really happy with the way I came up with to lay it out.

The first time, I drew a circle and drew cords the length of the radius. Something was off a little bit and I had to play with the length of the cord to get it to fit evenly.

This time I cut an equilateral triangle 15" on a side for a pattern and ran it around a pin in the carpet and marked the corners.

From the center of one side to the opposite point is 13". Accounting for a 1/2" hem, This gives a 25" parachute.
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  #12  
Old 07-16-2020, 11:17 AM
RobVG RobVG is offline
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Mostly done. Maybe a few more stickers.
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  #13  
Old 07-16-2020, 11:48 AM
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ghrocketman ghrocketman is offline
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Looks interesting.
What size power ? 24 or 29mm ?
What is your intended engine for the initial flight ?
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When in doubt, WHACK the GAS and DITCH the brake !!!

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  #14  
Old 07-16-2020, 12:08 PM
RobVG RobVG is offline
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I flew it before painting it. Tried to post a video but it was too large.

24mm. D12-5. Too long of a delay. Looked like it was going to slam into the ground. Just bought some D12-3's.
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  #15  
Old 07-16-2020, 12:16 PM
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ghrocketman ghrocketman is offline
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Try an E12-4 or an E30-4.
I was afraid you were going to say D12-5 and would have predicted that delay far too long.
Many of the Aerotech RMS24 offerings would be better too starting with the D15-4T.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't !

Failure may not be an OPTION, but it is ALWAYS a POSSIBILITY.
ALL systems are GO for MAYHEM, CHAOS, and HAVOC !
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  #16  
Old 07-16-2020, 12:23 PM
RobVG RobVG is offline
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I'll try the E's, if I can find a larger field
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  #17  
Old 07-16-2020, 12:50 PM
SCooke123 SCooke123 is offline
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Quote:
Originally Posted by Tau Zero
(nostalgic sigh) Ah, yes, windbreakers. I wore one regularly in the early 1970s...

G. Harry and Bill Stine in the Handbook of Model Rocketry, 7th Ed., say,

"My experience indicates that the shroud lines should never be shorter than the major dimensions of the parachute canopy. Thus, a 12-inch parachute should have shroud lines at least 12 inches long. I have also used shroud lines one and one-half times the major dimension of the canopy and won a few Parachute Duration contests with these." (pp. 182, 3)

So there's your minimum length. Other rocketeers have suggested 2 to 3 times the diameter of the chute.

Anybody else want to chime in here?


Our own Chris Michielssen (hcmbanjo) suggests the following method for avoiding tangled shroud lines (also see the excerpted diagram below):

https://www.apogeerockets.com/educa...wsletter368.pdf


More good tips from Chris:

http://modelrocketbuilding.blogspot...arachute+shroud

.



Those were some pretty good tips - thanks for the links!
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