List,
You asked for it ... here it is. The opinion from inside the cockpit of the
Burkland's 411 car. I appreciate Tom taking the time to write this today.
Wes
----------
Subject: RE: Clarifying Wheel driven Records
Wes,
Thanks for your efforts in making this neat trophy happen. I
would hope that Jeff will continue his artistic renderings of other land
speed racing subjects. There are so many interesting people, projects,
and stories to apply his talents to.
Appreciate the positive comments from all your chat line
friends. After watching the video I'm not sure if it isn't just about as
much fun seeing it happen from the outside. That doesn't mean I would
give up the inside viewpoint though, because it's also quite a ride.
The questions about power and weight on our car require one of
those "it depends" type answers. The weight is 4250 lbs empty with 440
lbs of water, 438 lbs of fuel, and driver for a total of right at 5300
lbs leaving the starting line. The fuel burn will put the car at about
4980 lbs exiting the fifth mile. The power available is 2350 HP per
engine so with all in sync you have 4700 HP at full throttle and RPM.
The run at World of Speed used just over half throttle exiting the
timers with only 5800 RPM. The actual power produced at those conditions
is probably in the 2900 HP area. You'll surely ask, "why not use all of
the available power to go faster?" One of the most difficult problems
with operating one of these cars is the drivability factor of being able
to modulate delivered power to match the available traction
capabilities. If this is done correctly it will result in traction
limited acceleration for the entire distance. If it is not done well the
car will loose acceleration and distance from under power or loose
acceleration and distance from excessive wheel spin caused by over
power. All of this critical throttle application has to happen, along
with appropriate shifts, in a somewhat confined space that is in a
fairly severe vibration environment. Our combination has had much effort
dedicated to fuel delivery curve shape, throttle linkage geometry, gear
ratio selection, inlet configuration, engine torque curve shape, etc to
simplify the drivers task of applying enough power to slip the tires
without spinning them excessively.
This entire discussion should point out the huge amount of
excess power one of these cars must have at low speeds to be able to
reach the trap speeds required to be competitive. Remember that the
constant speed horsepower requirement for the car increases as the cube
of speed. If the acceleration rates required to actually reach the trap
speeds within realistic distances are factored in the power requirement
quickly exceeds the available traction. The approach we have taken is to
use as much of the excess power at low speed to accelerate the car
quickly before the aerodynamic drag starts to use up the majority of the
power. With today's limited race track lengths this relatively quick
acceleration is almost a requirement to reach record speeds.
Hope this helps with some of the questions.
Thanks
Tom Burkland
-----Original Message-----
From: Wester S Potter [mailto:wspotter@jps.net]
Sent: Tuesday, January 23, 2001 10:10 AM
To: Gene & Betty Burkland; Tom Burkland
Subject: FW: Clarifying Wheeldriven Records
----------
From: Dave Dahlgren <ddahlgren@snet.net>
Date: Tue, 23 Jan 2001 07:06:47 -0500
To: The Butters Family <bbutters@coldreams.com>
Cc: Wester S Potter <wspotter@jps.net>, Jonathan Amo
<webmaster@landracing.com>, Malcolm Pittwood <MPittwood@compuserve.com>,
LSR
List <land-speed@autox.team.net>
Subject: Re: Clarifying Wheeldriven Records
i was at the 4 when Tom went by on that 450 pass and he
looked mighty hooked up to me. I would think if there was a
500 mph car with a piston engine that is constructed today
he is the man. he went by like it was an easy test pass
going down the track and both engines where pulling very
nice. It did make all the right sounds, two very happy
engines with the tune up he had. When they are right you can
hear it , at least i can. I have spend over 30 years tuning
up race engines and they have a certain set of
characteristics in the way they sound under a load that says
a lot about how they are running. I am not sure I can
describe it but it does not matter 2 cylinder or 16 high rpm
or low. It is more about the spacing of the power pulses out
the exhaust and relative pitch from one pulse to another.
When you hear it and recognize it you won't forget it. Kind
of like a musical instrument that is in perfect tune is the
closest i can describe it. Toms car was making all those
noises. The only other way you can sense it is the car seems
to be moving effortlessly with nothing in the engine
straining to get the job done. When they are not right the
only way I can describe it is the engine sounds all pi&&ed
off.
Dave Dahlgren
( with obviously no passion for a well tuned engine and
racing in general)
The Butters Family wrote:
>
> The last issue of Bonneville racing news had an article on
designing
> a 500 mph wheel driven car. I had to think, it has already been
designed.
> Tom will rip up the course given the right conditions and we will
never
> forget that day or the sound of the run. Kvach: some things are just
to much
> fun not to do them again.
///
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