Bryan;
It's all about energy; a material with little "stretch" will generate
very high peak loads for a very short time. A "stretchy" material like
nylon allows the load to be generated over a much longer time, greatly
lowering the peak load. Energy = power X time.
It's like towing another car with a chain-- take up the slack and BANG,
it breaks. A nylon tow strap simply stretches as the towed car gradually
gains speed. Ditto for parachutes.
Regards, Neil Tucson, AZ
-----Original Message-----
From: owner-land-speed@autox.team.net
[mailto:owner-land-speed@autox.team.net] On Behalf Of Bryan Savage
Sent: Monday, July 12, 2004 11:17 PM
To: Ed Van Scoy
Cc: John Beckett; Land Speed
Subject: Re: Chute Forces (1)
Were back to understanding the forces at work here.
I think you could put 5 turns of standard (cheep) duct tape on the
shroud
lines and it would slow the opening by 200 - 400 milliseconds.
They tried some 20,000 lb kevlar on Danny Boy and it snapped. Driver
felt a slight tug. About 310 mph.
3,300 lb 40% stretch nylon worked fine.
It sure made a believer out of me.
Bryan
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