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Re: Parachute

To: "Wester S Potter" <wspotter@jps.net>, "Keith Turk" <kturk@ala.net>,
Subject: Re: Parachute
From: "The Backus's" <34ford@email.msn.com>
Date: Sun, 5 Nov 2000 07:37:23 -0500
Wester, in the 70's most of us had the tether mount a bit too high (behind
the drivers shoulders on a "front motor" car) and it would often try to lift
the front wheels when the chute opened. It makes sense to me to have it as
low as practical to put weight on all 4 wheels, sort of like the "tractor
pull" trucks used to have the pull line attached almost in the middle of the
truck near the transmission. Not that I suggest that for LSR vehicles, but I
just think lower is better and in line with the center mass of the car
(probably at the cam height) is best.

John (309 A/F) Backus


----- Original Message -----
From: "Wester S Potter" <wspotter@jps.net>
To: "Keith Turk" <kturk@ala.net>; <land-speed@autox.team.net>
Sent: Saturday, November 04, 2000 9:14 PM
Subject: Re: Parachute


> List,
>
> This braking parachute question always leaves me wondering why the drag
> racers can slow from 300 mph passes with a parachute time after time
without
> very many incidents.  What is the big difference in slowing from 300 at a
> drag strip and slowing from 380 or so on the salt?  I'm sure I'm missing
the
> point here somewhere but something is at work on tethers and chute design
> for land-speed applications that is primarily solved in drag racing.  The
> discussion early this year on how to find the optimum point for placing a
> tether connection made sense as I read it.  The cars that have problems on
> the salt are primarily placing that connection in the wrong place and
> disturbing the balance of the car at speed.  I realize that drag cars
differ
> so little that once someone gets it right it's easy for everyone to do the
> same thing.  Not so with land-speed cars.  The basilc ability of getting
the
> parachute to deploy and do it's job seems to be the same however.  The
> tether straps are able to handle the same loads on dragsters, ribbon
chutes
> and the cross panel chutes hold up, what is so different on the salt?  The
> Burkland's car certainly had enough thought in the design area  for
braking
> but now Tom has gone back to the drawing board to see what he missed.
> Obviously the deployment of the chutes was at speeds higher than he had
> intended.  What's the answer?
>
> Wes

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