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Unread 05-02-2010, 01:06
vamfun vamfun is offline
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Re: Bungy and Surgical tubing

Quote:
Originally Posted by Ether View Post
I did a rough calculation to check this.


21.63 work done on load, joules

272 velocity of load at end of kick, inches/sec



If vamfun or MattH are reading this thread I welcome your criticism.

* http://forums.usfirst.org/showthread.php?t=14218


~
I did a quick check against my excel dynamic piston model and I get
23 joules and 231 in/sec so you are in the ball park with me.

I have the valves and a piping modeled and some approx to the dead volumes of the pistons. If I add a piping factor of .5 *Cv these drop to
22 joules and 219 in/sec.


Hmmmm: I must fess up to the 20in/s that I reported in this post:

http://www.chiefdelphi.com/forums/sh...90&postcount=1

Piston hammering was my concern and I'm in the camp that requires hard stops to prevent it for safety concerns. Foot speeds of over 300 in/s are required for long kicks and teams with pistons stopping the foot (even with a 10 to 1 lever arm are still reaching over 30 in/s).

As for rationale: I think LaFleur was spot on here. http://www.chiefdelphi.com/forums/sh...7&postcount=31

Last edited by vamfun : 05-02-2010 at 01:12.