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A simple question

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Ian S C17/03/2012 12:25:18
7468 forum posts
230 photos

Because. Ian S C

Terryd17/03/2012 12:34:55
1936 forum posts
179 photos

Why the Big Bang? Because it did!


AndyP17/03/2012 15:08:10
189 forum posts
30 photos

Google is your friend ! try this

Paul Boscott17/03/2012 15:47:26
99 forum posts
21 photos

May I rephrase the question to its more common form.

Why does a steam engine not work.

MichaelR17/03/2012 16:47:42
466 forum posts
74 photos

For that matter, Why does a IC engine work when it's trying to blow it'self to bits



Jeff Dayman17/03/2012 17:17:50
2221 forum posts
47 photos

"Why does a steam engine work ?"

'cause it has to feed the kids and pay the mortgage?

(That's the reason I work....)

Cheers JD

Richard Parsons17/03/2012 17:49:56
645 forum posts
33 photos

this is like the old conumdrum 'Why is a mouse when it spins' It is not a question it is a statement which defines a spinning mouse as 'WHY'

. I am off to feed the dogs an ger a beer or three



NJH17/03/2012 17:57:12
2314 forum posts
139 photos


No doubt on your return from the "beer or three" you will have an answer to the question - how authorative that may be is questionable! wink

I'm more concerned in the answer to the question " Why will MY ***!!!***!! vacuum engine not work!

( Google didn't help with that one!)

Anyone want to make an offer for a carefully and lovingly made doorstop!



Edited By NJH on 17/03/2012 18:01:24

wheeltapper17/03/2012 18:34:01
423 forum posts
98 photos

I'd like to make an offer but I've got so many doorstops I'm running out of bl**dy doors.embarrassed


Bazyle17/03/2012 18:54:57
6295 forum posts
222 photos

Norman. Picture? Published design?

Possibilities. Too hot to condense. Too cold and condensation too fast. Not enough volume at TDC for air content of charge. Flame not big enough to supply vapour charge.

Which came first the Mule or the Baby Mule? Well it is a simple question. And as you all know the answer why is there a problem with chickens and eggs.

Speedy Builder517/03/2012 18:56:42
2592 forum posts
207 photos

It could be the reason why windscreen wipers only break down in the rain. I guess your steam engine does not get steam in the right place at the right time. Like most engines - its a matter of timing.

Stub Mandrel17/03/2012 19:27:05
4315 forum posts
291 photos
1 articles

The interesting question is why does a steam engine work so differently on air to steam?


Terryd17/03/2012 20:26:36
1936 forum posts
179 photos
Posted by AndyP on 17/03/2012 15:08:10:

Google is your friend ! try this

That is HOW not WHY, said he, most mysteriously!!

Terryd17/03/2012 20:27:14
1936 forum posts
179 photos
Posted by Stub Mandrel on 17/03/2012 19:27:05:

The interesting question is why does a steam engine work so differently on air to steam?




Steve Withnell17/03/2012 20:50:29
843 forum posts
222 photos

How dare you accuse my steam engine of hysteria when running on air!

Nicholas Farr17/03/2012 22:18:45
3311 forum posts
1529 photos

Hi, maybe it is something to do with Newton's Third Law.

Regards Nick.

Robert Dodds17/03/2012 22:40:54
317 forum posts
59 photos


As an apprentice I took Heat Engines as part of my HNC. Didn't do particularly well at it but I'll never forget the " Steam Entropy Tables" that we had to resort to to work out the power output from steam engines, turbines etc.

Its somthing to do with the energy of the water molecules in addition to the energy from the compressed gas that makes performance on steam so different to performance on compressed air .

There's a lot written on Google about Entrpy of Steam and I still can't get my head round it!

Bob D

Steamshy19/03/2012 20:03:09
38 forum posts
2 photos


Steam engines have to be warmed through properly to run, I`m guessing that as things heat up, so they expand, not all materials or parts are the same thickness either,[ not counting dissimanal metals which heat at different rates]. So maybe friction may have a bearing on why a steam engine wont run on steam but air it`s ok. Once it runs ok on steam it usually does after quite well.

I know on Large turbines prior to running there is a steam chest warming sequence, which allows the control pistons and large mass of metal in the steam chest to expand correctly,


Stub Mandrel19/03/2012 21:07:21
4315 forum posts
291 photos
1 articles

The heat difference is the key.

A steam engine is a heat engine. It gains most of its power from the steam giving up its heat to do work in expanding, something that is further improved by superheat. Air going through a steam engine has far less energy stored in it and can do far less work for the same pressure.

A steam engine can be made more efficient by adding a cold condenser to create an exhaust vacuum. If you made an air engine create its own vacuum, it would take more energy than you got out, unless it was so cold it liquified the air.

It'sa fascinating subject that I'm only beginning to understand - the likes of Watt, Woolf etc. were very clever folk.


Ian S C20/03/2012 11:27:21
7468 forum posts
230 photos

Running a steam engine on air, could the exhaust be connected to the suction side of the compressor as well as the pressure side to the intake, would that have a similar effect to a condenser on a steam opperated engine? Ian S C

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