Is that called thinking from UNDER the Box? K
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> From: Chris R Harris <yesford@clear.net.nz>
> To: John Beckett <landspeedracer@email.msn.com>; Glen Barrett
<speedtimer@earthlink.net>; DOUG ODOM <popms@thegrid.net>
> Cc: Wester S Potter <wspotter@jps.net>; land-speed@autox.team.net;
Jonathan Amo <webmaster@amoproductions.com>; Keith Turk <kturk@ala.net>
> Subject: Re: Parachute
> Date: Wednesday, November 08, 2000 3:24 PM
>
> Easily fixed John, put the Mustang body back on !!
>
> Cheers,
> Chris Harris New Zealand.
>
> ----- Original Message -----
> From: "John Beckett" <landspeedracer@email.msn.com>
> To: "Glen Barrett" <speedtimer@earthlink.net>; "DOUG ODOM"
> <popms@thegrid.net>
> Cc: "Wester S Potter" <wspotter@jps.net>; <land-speed@autox.team.net>;
> "Jonathan Amo" <webmaster@amoproductions.com>; "Keith Turk"
<kturk@ala.net>
> Sent: Wednesday, November 08, 2000 4:53 AM
> Subject: Re: Parachute
>
>
> > OK guys, since my car was the reason to re-start this thread let me
give
> you
> > all some background. This is a very complicated situation. And requires
> some
> > experimentation in order to sort thing out.
> >
> > As some of you have mentioned LSR cars are different that Drag cars and
> > there are many reason why what works on one does not work on the other.
My
> > personal belief is that weight and aerodynamics plays the major role in
> > this. Our cars are usually more aerodynamic and much heavier. Here's my
> long
> > story, and I'm open to suggestions.
> >
> > My car was originally built with a Mustang II body as a chopped top
Comp
> > Coupe. Using a Simpson 12' crossform drag chute, standard tether line.
> > Everything was fine, safe and secure after repeated 200+ MPH runs. The
> > problem came up after I changed the body to a Chevette, same chassis.
Now,
> > for what ever reason, probably an aero issue, using the chute at high
> speeds
> > caused the car to turn left and slide until the chute drag would pull
it
> > straight again. It was later reported that the chute goes up in the air
at
> > about a 45 deg angle, which probably unloaded the rear off the car.
> Remember
> > the ONLY thing changed here was the body.
> >
> > Here's what I tried to solve the problem after discussions with various
> > manufactures and racers:
> > Raised spoiler angle to create turbulence, no change.
> > Tried Stroud drag chute, approximately 10' diameter, no change.
> > 12' tether line extension, no change.
> > Smaller 8' crossform chute, now sometimes whips back and forth.
> > 30' tether line extension, better chute angle, about 30 degrees
now,
> no
> > whipping, but still have problem.
> > Raised chute mount (as per Jim Diest) by 12". Problem is now worse
as
> > the car pulls right and won't pull back when the chute is open.
> >
> > With this particular car "everybody" is guessing. Obviously the air
behind
> > the new body is going up in the back and taking the chute with it.
Would
> > love to see that in a wind tunnel. Must be a ton of drag. How much
faster
> > would this car be if the air came together smoother?
> >
> > We had made the decision to go for a longer tether, 60' to 80', along
with
> > lowering the mounting point back to the original location, when Joe
made
> his
> > off road excursion. I personally feel this will solve the problem. We
need
> > to get the chute to deploy well beyond the weird air behind the car. I
> don't
> > see any other solution. As Joe mentioned we are also going to be
working
> > with Bob Stroud to solve the problem and will keep you all posted on
> > results.
> >
> > Another part of the problem here, is the time it takes to experiment.
I've
> > learned that each and every car is different in LSR. Bonneville is a
> > relatively safe place to experiment with these issues (wide open
space),
> but
> > the time (typically once a year) and the seat time factor is a problem.
If
> > we raced more frequently (as typical drag racers do) we could sort
these
> > problems out much sooner and our collective (LSR) learning curve would
be
> > quicker. Maxton offers us Easterners six time a year to experiment, but
> due
> > to other engine problems we were dealing with we didn't get the time to
> > investigate the chute problem as we should have. Obviously we should
have
> > addressed the chute issue first, but with a typical racers mentality we
> > concentrated on going fast instead. In retrospect a poor decision.
> >
> > So that's the story.
> >
> > John Beckett
> >
> > ----- Original Message -----
> > From: "Glen Barrett" <speedtimer@earthlink.net>
> > To: "DOUG ODOM" <popms@thegrid.net>
> > Cc: "Wester S Potter" <wspotter@jps.net>; <land-speed@autox.team.net>;
> > "Jonathan Amo" <webmaster@amoproductions.com>; "Keith Turk"
> <kturk@ala.net>;
> > "John Beckett" <landspeedracer@email.msn.com>
> > Sent: Sunday, November 05, 2000 11:18 AM
> > Subject: Re: Parachute
> >
> >
> > > Hi List
> > > Last tuesday night this drag chute issue came up again on the chat
line.
> > As a
> > > person that see's every run on the dry lakes and at Bonneville from
my
> > seat in the
> > > timing trailer I would once again say a couple of things.
> > >
> > > When the chutes first started coming out in the early sixties on the
> salt
> > it was a
> > > guessing game as to size, mounting, weather to pull it under power,
or
> > during
> > > decelaration, how long the tow line should be etc.
> > >
> > > Jim Deist has more experience then anyone on high speed chutes. He
was
> the
> > key
> > > player for a lot of the pioneers on the salt and the lakes. The drag
> > racing scene
> > > is a whole different world. The cars are basically the same by class
> > design, and
> > > are under different course conditions. Our courses are 1 3/10 long on
> the
> > dry lake
> > > to 13 miles long on the salt.
> > >
> > > The winds can very from a cross wind to a tail wine from one run to
the
> > next on
> > > the dry lake. At Bonneville along the long course from start to turn
out
> 7
> > miles
> > > down the course the wind, depending where you are can be blowing
> different
> > > directions as you make the run
> > >
> > > Other then the typcal questions and many answers about chute
mounting,
> tow
> > line
> > > length, size, type of canopy the other thing that is a critical
factor
> is
> > taking
> > > proper care of the chute during and after the exent.
> > >
> > > The conditions we run under are far different than drag racing. So
> forget
> > about
> > > drag racing. At El Mirage and Muroc we run under two differnt kinds
of
> > desert
> > > dirt. The dirt at El Mirage is more gritty and at Muroc a fine talcum
> > powder like
> > > base. Muroc is more dificult to get rid of on anything. El Mirage is
> dirty
> > but can
> > > be cleaned a lot easier.
> > >
> > > Now Bonneville is a different story all together as far as chutes.
There
> > are
> > > vehicles that only run on the salt and the chutes and maintaing them
are
> a
> > little
> > > different. The salt can be very dry as the this year or wet as past
> years.
> > > Regardless the chute must be clean, dry and properly packed to
function
> > well.
> > >
> > > We in the tower see some very scarry chute deployments and some
picture
> > perfect
> > > ones. Some come out in a blob and bounce along the course, others fly
> high
> > and
> > > whip or lift the back of the car off the ground, some spin and choke
the
> > canopy
> > > down, and some simpley drop the pilot chute out and nothing happens.
A
> lot
> > of
> > > times a small burr on the release cable will not pull through the
nylon
> > loop,
> > > other times the chute pack is dirty, wet or starched with salt and
let
> dry
> > in this
> > > condition.
> > >
> > > Simply rinsing out the chute will not always assure the chute is
going
> to
> > work. I
> > > have seen on several occasions chute panels rip and cause the car to
> veer
> > off
> > > course. he main reason is the panels when folded are not dry and the
> seams
> > or fold
> > > with the starch effect allows the tear to start a little easier.
> > >
> > > At El Mirage because the events are smaller and closer to everything
as
> > well as
> > > almost every run on video tape the drivers can see whats going on
with
> > their car.
> > > We in the tower make note of anything unusual and then notify the
crew
> in
> > the push
> > > truck and the inspectors. There have been several cases that we could
> see
> > daylight
> > > under all four wheels on cars. Short tow line, mounted to low, canopy
to
> > large for
> > > vehicle, it goes on and on.
> > >
> > > The driver don't always know whats going on as he is busy getting
things
> > shut down
> > > ond trying to turn out. The point here is there is never going to be
a
> > perfect
> > > answer to how to mount, size, tow line length etc. But we try to help
> from
> > our
> > > standpoint in the timing stand to let everyone know when we see a
> problem.
> > > everything is critical at speed, everything is critical on how well
it's
> > > maintained.
> > >
> > > If you are not sure what the vehicle send a crew member down the
return
> > road and
> > > have them watch the car during shut off. Get a better idea what the
car
> is
> > doing.
> > > Don't just put on a surplus chute and think it will work in a
emergency.
> > It won't.
> > >
> > > Get used to using the chute every run as some time you might need it
> when
> > the
> > > car,cockpit is filled with dust or smoke. Having to look for
something
> > like the
> > > chute release is poor under these conditions. It should be automatic
as
> is
> > using
> > > the brakes. It could save a lot of problems.
> > >
> > > If you still have questions, ask the racers who over the years worked
> with
> > the
> > > experts and found thie chute can be your best friend or your worst
night
> > mare if
> > > not correct for the vehicle. This site can get you a wealth of
> information
> > or
> > > where to go for it.
> > >
> > > Glen Barrett
> > > Chief Timer SCTA / BNI
> > >
> > > DOUG ODOM wrote:
> > >
> > > > 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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