OT Air vs. Steam ?

Caryc

Well-known Member
I was watching an artist show this morning. This artist and wife were at the "Miracle of America" museum in Polsen Montana.

They had a treasure trove of old equipment there. They showed his wife riding on one of those old huge steam tractors, except they said the correct name was a steam traction engine. The artist later painted a picture of this machine.

The big tractor was towing something behind it that I couldn't figure out as far as what it was. Anyway, the driver of the tractor later explained that for safety reasons they don't run those old machines on steam. They run them on compressed air. That explains what the tractor was towing behind it. It was a very old looking rust colored air compressor.

They guy said that any steam engine can be run on compressed air. That thought just never entered my mind before. While the big tractor was running, they showed the face of a very large gauge which I figured to be the steam pressure. But that must have been the air pressure. It read 90 pounds if I remember correctly.

I just wonder what all they had to do to get that thing to run on air like that? I didn't realize until they explained that the thing was running on compressed air that while the thing was running I didn't see any steam exhaust even when they blew the whistle!

I wonder about the power difference between running on steam and running on air?
 

https://en.wikipedia.org/wiki/High-pressure_steam_locomotive

A high-pressure steam locomotive is a steam locomotive with a boiler that operates at pressures well above what would be considered normal. In the later years of steam, boiler pressures were typically 200 to 250 psi (1.38 to 1.72 MPa). High-pressure locomotives can be considered to start at 350 psi (2.41 MPa), when special construction techniques become necessary, but some had boilers that operated at over 1,500 psi (10.34 MPa).

Abner Doble, whose motto was: "the best isn't good enough" made incredible steam cars in the 30's. 100,000 mile guarantee, flash tube boiler, Murphy custom body, 1000 ft. pounds torque at ONE RPM! Howard Hughes said he wouldn't drive anything but a doble.

Kind of like today's Tesla.
 
(quoted from post at 11:25:16 11/02/14)
https://en.wikipedia.org/wiki/High-pressure_steam_locomotive

A high-pressure steam locomotive is a steam locomotive with a boiler that operates at pressures well above what would be considered normal. In the later years of steam, boiler pressures were typically 200 to 250 psi (1.38 to 1.72 MPa). High-pressure locomotives can be considered to start at 350 psi (2.41 MPa), when special construction techniques become necessary, but some had boilers that operated at over 1,500 psi (10.34 MPa).

Abner Doble, whose motto was: "the best isn't good enough" made incredible steam cars in the 30's. 100,000 mile guarantee, flash tube boiler, Murphy custom body, 1000 ft. pounds torque at ONE RPM! [b:c997ea93c8][color=red:c997ea93c8]Howard Hughes said he wouldn't drive anything but a doble[/color:c997ea93c8].[/b:c997ea93c8]

Kind of like today's Tesla.

Howard Huges also built a huge flying boat that was like an albatross around his neck. :wink:
 
Looks like Tall T is up to snuff on steam power. There is a program on the tube called Ultimate Restoration- Last week they were restoring the Sierra #3 Locomotive one of five still in existence built around 1897. It was used in a lot of movies and tv shows. A team was restoring it, a very good show. There are bits and pieces of the restoration on youtube if your interested.
 
Even a colossal failure, doesn't make an enterprising inventor a fool.

Hughes also came up with his own version of a steam car where he put the steam generators in the doors. But they said he should have just duplicated what Doble had already done and then added a few refinements to solve the freeze up problem. Doble put a little alcohol in the water as antifreeze.

What looked like beautiful nickle plated rads up front on Doble's Model E steamers, were actually his recondensing systems.

Thanks WW2N, I'll check it out.
 

Thanks but you all seem to have missed my point. My point was that they had that huge steam tractor running on compressed air.

I was wondering about the logistics and what all had to be done to get one to run on compressed air like that.

I'm just as amazed at the old steam powered machines as you guys but it sure seems a lot safer to run one on compressed air for show purposes.
 

Sorry . . .

I've been curious about air driven engines too but know next to nothing on that score.
 
(quoted from post at 13:17:14 11/02/14)
Sorry . . .

I've been curious about air driven engines too but know next to nothing on that score.

I kind of figured that among the old codgers (including me) here that someone might know something about converting one to air power. But maybe it's not really that common, after all, I never heard of it being done until I saw that show this morning.
 
(quoted from post at 16:00:46 11/02/14)
Thanks but you all seem to have missed my point. My point was that they had that huge steam tractor running on compressed air.

I was wondering about the logistics and what all had to be done to get one to run on compressed air like that.

I'm just as amazed at the old steam powered machines as you guys but it sure seems a lot safer to run one on compressed air for show purposes.

I would guess they plumb the compressed air supply into the steam outlet from the boiler. Boiler is probably the most likely point of pressure failure in an old steam engine.

TOH
 
Steam traction engines are a regular feature at Midwest "Threshing Festivals." Awesome machines in size and power. I believe their plow pulling capacity was measured in tens of bottoms. Prairie Busters.

I've only seen them operate as originally built...with steam generated from a wood or coal-fired boiler.

Colin, MN
 
If im not mistaken a steam engine has to be pressure tested fot
use in a public event. Boiler explosions are very ugly things. A
steam engine can be run on air easily by putting a t in between
the outlet of the boiler, as long as it has a check valve, and the
inlet of the engine. It works ok and is safer but you would need
an air compressor the size of a car to give you enough CFM to
power it I would think. Ive only seen it done with a model of a
stationary engine that was about 6" tall. From what I saw it
would be so inefficient it would be to costly even for a hobby.
 
(quoted from post at 14:31:49 11/02/14) If im not mistaken a steam engine has to be pressure tested fot
use in a public event. Boiler explosions are very ugly things. A
steam engine can be run on air easily by putting a t in between
the outlet of the boiler, as long as it has a check valve, and the
inlet of the engine. It works ok and is safer but you would need
an air compressor the size of a car to give you enough CFM to
power it I would think. Ive only seen it done with a model of a
stationary engine that was about 6" tall. From what I saw it
would be so inefficient it would be to costly even for a hobby.

The compressor that the thing was towing to power it was about the size of a regular two wheeled compressor you'd see being towed by a pick up truck today. Maybe just a might smaller.

It seemed to give all the power needed to power the machine for just running on it's own. Power to pull something would probably be a whole other story. When the driver pulled the lever for power forward, it gave one heck of a lurch. The lady passenger was holding on to one of the uprights holding up the canopy and it's a good thing she was holding on well.
 

Since steam engines run by directing the steam from the steam jacket that surrounds the fire box on most sides. I can't see that you would have to do anything more than build up air pressure in the steam jacket. Of course you would have to have a source of compressed air on wheels with it. most likely any one of many gas or diesel powered mobile compressors.
 
A steam engine is valved to direct steam pressure to the piston. The steam pressure pushes the piston down the cylinder to generate power. At the bottom of the cylinder the inlet valve closes off the steam and the exhaust valve opens to vent the steam. Once the piston returns to the top of the cylinder the steam valve again opens to let steam in pushing the piston down the cylinder...and so forth. The engine will run with steam pressure, air pressure, pressure from a CO2 tank, etc. It only needs pressure, the valve timing takes care of the rest.

As others have posted the air pressure is likely used since many states required the boilers to be tested/certified which can be costly. If you plumb the air pressure directly to the engine, then the boiler will see no pressure. So the only change is a simple plumbing connection.

It is interesting to note the Stanley Steamer (car) did not carry steam in the boiler but rather in the tubes within the boiler. Since the steam pressure was in many small tubes a leak/rupture in a tube would simply put steam into the boiler putting out the fire - much less chance of an explosion.
 
No need to have the boiler or the "steam box" as you call it in the circuit or pressurized.

That's the whole reason for running the engine on air... that the boiler can't be certified as a pressure vessel.

Simply pipe the compressed air directly to the throttle valve/governor and the steam engine will run happily on compressed air.
 

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