List,
I sent some comments on the 411 car to Tom Burkland. This is his reply to
one of the postings.
Wes
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Date: Wed, 7 Feb 2001 06:46:09 -0700
To: wspotter@jps.net
Subject: RE: going fast
Wes,
As for John's comments on the challenger, The front and rear
axles/engine pairs were not connected except for the traction on the
ground and the throttle rigging. The left and right pairs were connected
through the axles which had two ring and pinion sets on the common
center shaft, one for each engine/transmission combination. Another
point of interest was the use of cyclone overdrive gearsets outboard of
the quickchange center sections to get the required overall final drive
ratios.
For the record any of these cars with record potential will be
slipping all tires under power and some means of controlling all wheel
speeds must be provided. The B&N rhino car, Thunderbird turbine, and
Mickey's Autolite car are examples of using the ground to connect the
two powertrains. Since the basic axle weights are hard enough to match,
let alone the dynamic transfer and aerodynamic applied loads, the
traction will never be completely matched between the two axles. Throw
into this mix the difficulty of matching the power delivery of two
drivetrain combinations (the Autolite car even had different engines,
one blown and one injected) through out the operating rpm range and the
driver has an impossible task. This could potentially be managed by some
sort of throttle by wire traction control system if the engines tolerate
the rapid throttle cycles produced by this type of arrangement. The
other very real difficulty comes from the rough track situation were not
all wheels or axles may be on the ground at any given instant. The
ability of the car to distribute power to the wheels that have traction
and prevent engine overspeed is important during these events.
Hope this helps clarify the design requirements.
Thanks
Tom Burkland
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