List,
Obviously there are many factors that determine what is needed in a
parachute. My first chute was a military surplus 16 ft. ring slot.
Worked real well on our roadster at speeds from 150 to 200 MPH. It's
mounting height was at the bottom of the body. It saved my butt during
a spin. I have a picture of the car facing a fully deployed chute. When
it came out it turned the car and we coasted to a stop.
Like many other issues that are put on the table for discussion, we tend
to get things too complicated. Glenn's suggestion of talking to Deist is
good advice. The weight of the car, the speed, the aerodynamics all play
a part. And Glenn's advice about care of the chute is primary. I have
had chute failure, even when it was clean, if it had been packed too
long.
Glenn spoke of high flying chutes, again an aerodynamic condition that
we have experienced, but that is not a problem if the tow line is long
enough. I don't believe that cross winds are a problem in chute
deployment either. If you are traveling 200 MPH, a 20 MPH crosswind will
have little affect until the car slows.
DOUG ODOM wrote:
>
> Jim; Would that system (reefed) work on a LSR vehicle? If so why is it
> not being used? Doug
>
> Jim Dincau wrote:
> >
> > Doug,
> > The chute when it blossoms is in a "reefed" condition. A line holds the
> > shroud lines close together where they connect to the canopy. After a delay
> > this line is cut and the chute opens fully. This technique is used in a lot
> > of instances when dealing with heavy loads.
> > Jim in Palmdale , who once worked at a place that manufactured "reefer
> > cutter" charges.
> >
> > ----- Original Message -----
> > From: DOUG ODOM <popms@thegrid.net>
> > To: Wester S Potter <wspotter@jps.net>
> > Cc: <land-speed@autox.team.net>
> > Sent: Sunday, November 05, 2000 7:16 AM
> > Subject: Re: Parachute
> >
> > > Wes; My $.02 worth. The big difference between drag cars and LSR cars
> > > is the size of the tire you have on the ground and the weight of the
> > > car. I don't know of many drag cars that run 7 or 8 hundred pounds of
> > > ballast. On the really fast LSR cars I would think they would copy the
> > > Air Force or space shuttle type of parachute deployment. The other day
> > > on TV I saw the space shuttle land and the chute was out before the
> > > wheels touched the ground but it looked like it was rolled up so it
> > > unfurled and got bigger the longer it was out. Is this a way to soften
> > > the hit?
> > > Doug Odom in big ditch
> > >
> > > Wester S Potter wrote:
> > > >
> > > > 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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