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Re: Parachute lines

To: kturk@ala.net, Dave <ddahlgren@snet.net>,
Subject: Re: Parachute lines
From: Dick J <lsr_man@yahoo.com>
Date: Tue, 7 Nov 2000 11:07:03 -0800 (PST)
Keith, it came out OK in E-mail.  You could also
move the fulcrum to the center and run the shock
the other way so that the entire assembly
wouldn't all be mounted so far back in the car.

Dick J 


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--- Keith Turk <kturk@ala.net> wrote:
> Dave I think I finally caught on to what you
> were saying... Try this....
> 
> FIXED mounting point of one end of the Rod....
> Shock at the upper end with
> a second rod hanging out the back... when you
> pull aft on the second
> Parachute attaching rod you are pulling down on
> the Shock.....
> 
> don't know if that made a lick of sense but I
> understood it perfectly.... 
> 
> o------------  ------------ O
>              s               I
>              h               I
>              o               I
>              c               I
>              k               I
>                               I
>                               I
>                               O
>                      parachute
> 
> now I wonder how that will come out on an
> E-mail
> 
> K
> ----------
> > From: Dick J <lsr_man@yahoo.com>
> > To: Dave <ddahlgren@snet.net>; Wester S
> Potter <wspotter@jps.net>
> > Cc: Nafzger <nafzger@vtc.net>;
> land-speed@autox.team.net
> > Subject: Parachute lines
> > Date: Tuesday, November 07, 2000 12:47 PM
> > 
> > It would seem like a vintage 125 dirt bike
> shock
> > would be just the thing for that.  They have
> nice
> > long travel and a good progressive rate
> beginning
> > the first inch or so of compression with
> about
> > twenty pounds and increasing to 500+ pounds
> > before they bottom out. Use a 2:1 arm and it
> > should never reach bottom-out.  Migth be a
> good
> > engineering experiment coming out of this.
> > 
> > Dick J
> > 
> > 
> > --- Dave <ddahlgren@snet.net> wrote:
> > > 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
> > 
> > 
> > =====
> > * * * * * * * * * * * * * *
> > *         Dick J          * 
> > *    (In East Texas)      *
> > *         # 729           *
> > * C/GRS   C/FRS    D/STR  *
> > * * * * * * * * * * * * * *
> > 
> >
>
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