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Steam dragster clutch

Posted by john fehn 
Steam dragster clutch
November 12, 2006 01:14AM
Steam dragster clutch

One problem I have when trying to design my steam project is how to arrange a clutch into the system. As we all know, the standard automobile clutch is incorporated into the so called 'bell housing' on the engine block. The only completely separate clutch I happen to know of is a Harley-Davidson hog clutch.

But looking at this picture of the Chuk Williams steam dragster,

there seems to be a separate clutch unit. It looks suspiciously like a brake drum. Could someone please give me the details on that unit? Thank you very much.

Budapest John
Re: Steam dragster clutch
November 15, 2006 11:38PM

"Suspiciously like a brake drum"--well, it is a modified
brake drum!! Designed and built by one of the team members-Jim
Tangeman, it works very well. Too well, actually..We recently
replaced it with a conventional clutch from a Ford Mustang. What I
mean by working too well--upon engagement it locks up very quickly,
and that was causing the engine to bog down a bit on take-off. The
new Mustang clutch slips just the right amount to let the engine
RPM stay around 1000-which keeps the feedpump doing its thing...
The brake drum clutch wasn't that easy to build-the shaft
is hollow with an O-ring joint to carry the fluid, and the master
cylinder had to be designed to work in a reverse fashion-not that
easily done!
For normal usage, I would recommend using a good conventional
clutch-keeping in mind the high torque that a steam engine can
generate at very low rpm. The Mustang clutch we used is bolted up
to the matching Mustang flywheel with a mechanical release mechanism
-is pretty clean and works very well.
If you want I can send you a photo of the newer clutch installation.

Cheers--Chuk Williams
Re: Steam dragster clutch
November 16, 2006 02:43PM
Chuk - years ago I had an IC engined round the pole model racing car. It had a centrifugal clutch with the shoes disposed on the flywheel just like your "brake clutch" with springs holding the shoes off the drum. The shoes trailed relative to the drum but obviously would bite more as the revs went up - was centrifugal force part of your problem?

Re: Steam dragster clutch
November 16, 2006 05:27PM
Sounds like a 1907 Packard model 30 clutch,,,At hi rpm [1400] it would not release,,as you wanted to shift,,,back off throttle an ease it to neutral,,revs go down in nutral,,clutch releases,,and now shift to high,,,It was an enternal expanding affair,,It had other clever tricks to keep your attention too,,,,nice car tho Cheers Ben
Re: Steam dragster clutch
November 16, 2006 07:44PM
Salsbury makes centrifigual clutches just for your purpose. The only thing to ask about is if they will fully engage at very low rpm.
Re: Steam dragster clutch
November 16, 2006 09:18PM
Thanks-everyone-for the suggestions. The clutch we have in the vehicle
now does the job very well-until I build a bigger boiler and really max out
the engine!! Then we may have to come up with a new heavier-duty one.

Yes I think that part of the problem was the centirfugal aspect,
but also a big part of it was the reverse mechanism that had to be
used to operate the "Brake Clutch". Keep in mind that when you depress the
clutch pedal with a normal hydraulic clutch, the master cylinder pumps
fluid into the slave cylinder which releases the clutch. We couldn't do that
with this one..because of the way a brake is designed. It is built to engage
when you put pressure to the slave cylinder...We had a set up whereby the
clutch pedal operated a spring-loaded lever. When you depressed the clutch pedal, the
lever released pressure on the master which released pressure on the slave
which...I'm sure you can take it from there.
Anyway, all this complicated linkage was very troublesome and required
constant adjustment..that's why I'm very happy with the Mustang clutch..


Edited 1 time(s). Last edit at 11/16/2006 09:19PM by chuk williams.
Re: Steam dragster clutch
November 17, 2006 10:15AM
Hi Chuk: yes, any pictures you have would be helpful. I can't imagine how you make that work without the Mustang engine block, bell housing, crank shaft, etc.

John Féhn in Budapest
Re: Steam dragster clutch
November 19, 2006 09:34PM

I've been gone all weekend, and just arrived back home...so I'll
get a photo posted tomorrow--OK?

Re: Steam dragster clutch
November 20, 2006 05:56PM

Sorry mate-I'd completely forgotten that I left the clutch-along
with the engine-at Art Gardiner's, and so it's not here to be photographed.
I actually went out to the shop with camera in hand, only to realize it
was still with the engine. We had problems with it at this years' Time
Trials, and so Art has been rebuilding the exhaust cam-which caused the
problems. I will be picking up the engine in a few months time, and if
you still need a pic-I'll do it then.
The clutch is a standard Mustang clutch, to fit the 2.3L engine...
and is bolted up to the stock flywheel with the teeth taken off and lightened
up a bit. I built a mechanical linkage to actuate it...pretty simple really.
The only problem I see with using one of these clutches-be sure you use a
heavy duty one, because they're built to take the relatively low torque
of their stock application.

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