Wes, thanks for getting this from Tom Burkland.
For the many of us who have only driven much
slower cars, it is awsome to read this account of
a run, then think about it while watching a video
tape from inside somebody's cockpit. You can not
only see and hear what's happening, but this
interview adds a dimension of knowing what the
driver is thinking and doing.
Dick J
.
--- Wester S Potter <wspotter@jps.net> wrote:
> 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
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