Some years ago, I was involved in the design and build of a Allison 250
turbine engine sprint car [dirt track]. The engine used for that car came
from the residual engines from the Indy car. It came as a pallet of parts
and tech manuals.

The car was configured as a 4 wheel drive sprint car, turbine engine
powered. Double radical design.

It ran successfully in competition with way more power than it needed,
however because it was built around a direct drive connection [at the
owners insistence despite my strong advice otherwise] the car was simply
not manageable in the short dirt track.
To make the corners at full power and speed off the straights it required
massive brakes to slow down against the engine at peak power..

After only a couple laps, the massive 4 wheel double caliper brakes were
glowing red hot... a couple more laps and the tires caught on fire from
brake heat.. serious energy management problem, to say the least.

Several fixes were tried, all within the owners [check writers] fixation
with direct drive coupling.. None worked... other than spend more of the
owners money.

I came forward with a modification of the compressor surge valve which
would dump compressor air, connected to a foot throttle.. so the driver
controlled not the fuel but the air available for combustion. This would
allow a needed reduction of power going into the turns with an almost
instant return to full power upon closing the modified surge valve.
Since this device played on the combustion can pressure wave front, if not
handled carefully, it could cause the engine to flame out, or to "Surge",
which is a condition where the flame front travels from the burner can
forward in the flow path and out through the compressor section ..
potentially with violence enough to destroy the compressor blades, so
driver has to know what to do to manage the engine.

The race season finished while the modification was being worked out, the
owner/check writer decided he had lost enough money pursuing his "pet car"
and the sponsors weren't impressed with it's poor showing on the circuit,
thus it got rolled into the back of the warehouse to be sold off for race
parts and who knows where it is now..

Power to weight ratio was really fantastic. The engine put out a constant
1,200 HP in a car that weighed 1,400 lbs, so the potential was there.. just
couldn't manage the power in the environment effectively.

On Sat, Sep 12, 2015 at 9:34 AM, Rich Thomas via Mercedes <
mercedes@okiebenz.com> wrote:

> cool.  I didn't read the earlier posts but figured someone must have
> remembered that.  Us Hoosiers I guess...
>
> I have this idea that there should be an "unlimited" race series, let the
> drivers assess the risk and have at it.  It would generate all kinds of
> interesting engineering and vehicles and perhaps safety innovations too.
> Enough of all the wimpy rules and restrictions.
>
> --R
>
>
>
> On 9/12/15 12:05 PM, Dan Penoff via Mercedes wrote:
>
>> I mentioned this early in the thread.
>>
>> I saw the car run twice (actually more than that if you include time
>> trials and carburetion day) and it was amazing.
>>
>> Yes, it dropped out with eight laps to go, not due to an engine issue but
>> a bearing failure in the transmission.
>>
>> The following year it was wrecked and never driven again.
>>
>> And of course USAC pretty much ruled it out of competition by mandating
>> an inlet opening that limited the top speed.
>>
>> Dan
>>
>> Sent from my iPad
>>
>> On Sep 12, 2015, at 11:09 AM, Rich Thomas via Mercedes <
>>> mercedes@okiebenz.com> wrote:
>>>
>>> Hey, y'all remember Parnelli Jones's turbine car at the Indy 500,
>>> right?  Mid-late 60s?  I think he ran it 2 years and it was cleaning up the
>>> first time until a transmission bearing broke.  I forget what happened the
>>> next year, maybe a crash?  Then the race organizers banned turbines.  I
>>> don't remember much about it, I was fairly young, but I am assuming the
>>> turbine just ran at some fairly constant RPM and the tranny handled the
>>> speed aspect.  I think the advantage was it had high torque that let him
>>> sprint out of the turns.  I should study that some.
>>>
>>> --R
>>>
>>>
>>>
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>
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