Boy Glen,
Words of wisdom on this subject at just the right time. I'm one of those
guys that had a chute NOT deploy one time, during my entry into the spin out
club. Probably pretty lucky. The failure mode was one that was not
previously mentioned. It was 93 WOS, a really wet meet after Speed Week had
been rained out. Earlier my chute was wet and salty. The nylon loop became
incrusted in salt and when the release was pulled the loop did not pull thru
the grommet. It was Starched larger than the diameter of the opening and
the Deist pilot would not overcome that "STARCH"
NEVER AGAIN. Actually I'm probably lucky that it didn't deploy, but the
spin was so slow that I could think, OK if I pull it now, it will be
straight down the course when the canopy blossoms. Yeah right.....
I have to second Glens comments about Jim Deist and his people. I spent
some time with one of Jims engineers doing the system for my Merkur. This
was in 1989 when the car was in the building stages. Given vehicle weight,
general aerodynamics and proposed speeds, (I'm sure he thought I was crazy
thinking an F P/S car would go beyond 200) he had recommendations and
directions about how to calculate mounting points. My system is a 12' pro
stock type of canopy with 21' shroud lines and an additional 40' of tow
strap to lessen the jerk. Joe explained how to triangulate from the canopy
back to the CG of the car, and where the point pierces the rear panel that
is where the mount should go. This is with a 4260# wet with ballast and
pilot. Pulling the chute at 208 was no problem. I realize this is
particularly slow for chute requirements, but the point is that help is as
near as the phone, and they have been doing it for a long time.
When after 8 years of use, Deist & Co, repaired, reworked for faster speeds.
(They believed) for nominal charges. The thing is on the car now, because I
just can't give my son Jim less safety than I had even though he is only
going 174. I do predict he will be a legitimate long course car next year.
I know that the dynamics of 300 and 400 MPH cars is dramatically different,
but a lot of things have been tried and I'll bet that the Salt Bear has been
involved with 80% of it. His engineers can discuss the jerk of deployment
and know how to make it less. Speeds of 400+ MPH though is still relatively
unknown except for a few.
I am sure though the failure of Burklands chutes at 450 MPH was a
surprise. His system does look to be well thought out. As mentioned earlier
I'm sure he is reevaluating and redesigning. Boy I'd like to see it go that
fast again. I was honored to be a witness. I saw video of what occurred at
the 11 mile and all I could think was What a ride it must have been.
It also shows me that I need to rethink everything I know as I plan on going
faster.
I have an aero guy and a computational fluids guy just chomping at the bit
for me to do a liner so they can address just these kind of issues, but you
can bet there will be some practical experience of Jim or one of his guys
included.
Cept the aero guy wants the car to be 5 sq ft.
He hears my comments/plans about a 4 cylinder lakester and just cringes but
at the same time does not volunteer to be the main sponsor.
Rick Byrnes
We have enough youth...........How about a fountain of smart
www.rbmotorsports.com
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