Thinking a little outside the box today.. I wonder if a spring and shock
arrangement on a rocker system would soften the hit of the chute.. If
you connect the chute line to a pull rod or rods and then go through a
rocker arrangement you could push on a spring and shock (coil over type)
and thereby take up the hit a lot softer. the same as driving with a
solid suspension everything breaks or cracks from all the instantaneous
loads. i see no reason why this could not work very effectively.. If
you know the speed and mass of the car and the square ft. of the chute i
would think that an appropriate spring rate and damping rate could be
calculated so the chute does not just bang open and tear things up.
Might even make some of the hard to handle cars a little smoother
too.... I am open for further discussion on this.
Dave Dahlgren
Wester S Potter wrote:
>
> Howard, List.
> The thing that disturbs me is that even after several years there are still
> tethers that can't handle the stress and snap so cleanly. I'm aware of the
> programming Deist does and the results have been impressive in stopping so
> many cars so many times, safely. What scares me is the fact that with the
> potental of eight or so 'liners capable of 400 mph speeds this next year.
> This should bring the probable result of two way record runs again. On the
> South end of the course there won't be mud for stopping. We don't need more
> "Breedlove stops" in a pond somewhere or someone running into a dike.
> As for a kevlar tether, the strength isn't necessarily longitudinal from
> what I have been able to read ... the impact resistance is based on a
> cushioning effect from the woven layers, of which there are several (and the
> friction between them is the shock absorbing quality), and the strength of
> the covering surfaces. Ballistic nylon is just that, ballistic, tough
> enough to slow the original hit
> What is needed is some strapping that will hold up under the shock of the
> chute deployment jerk. As an example, Polypropylene rope is stronger in
> some ways than nylon for the same number of strands and same thickness of
> strands. There must be some composite that could be core-spun or
> multi-fiber cording that could be manfactured to handle the load.
> Just brainstorming and I'm probably all wet but I'm very concerned about the
> potential for a dangerous situation.
> Wes
>
> PS ... We once towed a '50 Chev 2 door for thirty five miles on a very
> cold winter night using two strands of nylon shroud line from a parachute.
> The stuff is great until it gets a solid hit, as long as it can stretch a
> bit it's just fine.
>
> W
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