Stirling Engine Rally

Usual heads-up for this event at Kew bridge steam museum this coming Sunday

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Personally I felt it was a little down on interest last year, but it may just be that having gone every year since it started I am actually beginning to remember things I've seen before!

Nick H

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Nick H
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Nick,

Due to the magical word "overtime" I wont see you Sunday, I'm driving to Edinburgh Sunday ready for a job Monday and Tuesday then coming back to Lancaster for Wednesday and home then going back to Edinburgh on the Friday to work the weekend returning home on the Monday. If anybody wants stuff fetching email off NG.

Martin P

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Reply to
campingstoveman

What is this word "overtime"?, you mean you are not doing it for the sheer fun of it.

Never mind it should buy you a few gallons extra for the Rover.

Regards

Andy M

Reply to
andyengine

Andy,

The nature of my job means that "Overtime" is a very rare thing as our customers do not work weekends unless for exceptional reasons so when it is offered I grab with both hands :-)) plus none of the other engineers want to do it.

Reply to
campingstoveman

Only joking, I was told that the others at work could work overtime but because I was classed as an overhead I was not allowed to do it. Things have changed a bit now but there is not enough work in our department to do overtime.

Andy M

Reply to
andyengine

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I'm not sure whether it was down on numbers or not, but definitely seemed a bit 'quiet'. Still some interesting stuff to see though - there are a lot of people beavering away in their sheds trying to develop a practical Stirling engine and the fruits of their labours are always worth looking at.

Not too much on the vintage side; the usual 6" Ericsson was there and very pretty too, but the only thing I don't recall having seen before was a nice Ky-Ko fan.

Adrian of The Engineer's Emporium was there with a running example of the new Robinson model he has been advertising in SEM - didn't ask the price - and Kontax were there with a 'show special' on their jewel-like low temperature differential engines at only £60 in kit form or £65 built, I was tempted but managed to resist. I did however snap up a slightly damaged copy of Allan Organ's book "The Regenerator and the Stirling Engine" being sold for £20 in aid of museum funds - a good bedtime read!

All in still a worthwhile day out, but perhaps getting to be a rally I wouldn't travel too far for.

Nick H

Reply to
Nick H

I was disappointed to only see 3 people I knew and chat with only one for any length of time.

I had wanted to engage in conversation with one of the grand experts about why the heat engine with a single piston and stationary wire "displacer" worked at all!

Speaking of practical stirling engines I did learn that british gas, or whatever they are now called, are not supporting the stirling-in-the-kitchen 800W(e) chp system any longer, what went wrong?

I also didn't note the youtube url for the pressurised boat motor that was on display. After the first few exhibits of models my interest wanes and it's the more practical things like the Eriksson (1898?) that draw me. Mind the little 5bhp steam turbine genset in the standard display is a beauty.

I didn't stay long because it was a lovely day and the Henry Moore exhibition at Kew Garden was more of a draw to me.

Andrew Heggie

Reply to
AJH

"AJH" wrote (snip):-

Beats me - where is the asymmetry?

I believe the problems were economic rather than technical - eg the governement grants dried up. It was tragic to see all the kit from the UK sub-contractor up for auction when BG pulled the plug.

This is the only youtube ref I saw -

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- but I don't think that one's pressurised.

Nick H

Reply to
Nick H

Pass.

It was a horizontal piston/cylinder driving a crank and flywheel with no other connections. The "cylinder head" was a fixed horizontal test tube with the further most half (closed end) filled with what looked like stainless steel wool. The flame was applied at the junction of the wool and free air. I could only assume that an oscillation was set up and the air passing in and out of the wire wool transferred energy to the cold end and caused an oscillation, like those steam putt putt boats. tractor up for auction when BG pulled the plug.

OK I found it now though it is running un pressurised, previously I'd chatted with him but his stand was unattended when I was there. He describes the unit as one man power, it's rhombic drive and ptfe piston with no lubrication, he previously had it in a boat. On his stand it said he used spark erosion to get enough surface area for the hot side.

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Andrew Heggie

Reply to
AJH

"AJH" wrote (snip)

In order to run, the average temperature of the air inside a hot air engine must be higher during the expansion stroke that it is during compression (assymetry). This is normally achieved by two pistons (alpha configuration) or a moving displacer (beta and gamma) shuttling a portion of the air between the hot and cold spaces. In these single piston engines there is no immediately apparent reason why the temperature of the air should change with the direction of piston travel (other than due to the effect of compression and expansion itself, which of course acts in the opposite sense to that required for an engine). I have seen them described as 'thermo-acoustic' engines implying that the assymetry is introduced by some sort of resonant effect in the tube, I don't find this credible as even without doing any calculation it is evident that the speed of operation is far to low. Another name is 'thermal lag' engine which may be more revealing - is there perhaps a difference in the rate of temperature change of the air as it moves first in one direction through the wire wool and then back the other way?

Nick H

Reply to
Nick H

Another youtube clip to prove the damn things do work - though the comments do rather indicate a lack of understanding of why!

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Nick H

Reply to
Nick H

Actually I wonder if one of the comments does give a clue, that is that the piston end is a cold sink. So this engine has two cold sinks and air passes through the stationary regenerator and the volume expands and contracts but...

AJH

Reply to
AJH

See:-

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Nick H

Reply to
NHH

Bit late in the day but I tripped over this while looking for something else:-

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Nick H

Reply to
Nick H

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