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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