looking for some advice on 1st engine

Discussion on Stirling or "hot air" engines (all types)
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tapkoote
Posts: 13
Joined: Fri May 17, 2013 12:04 pm
Location: Washington State USA

looking for some advice on 1st engine

Post by tapkoote » Fri May 31, 2013 10:39 pm

Seem to be getting nowhere with this tin can engine.
The working piston is brass tube, filled w/ high temp RTV
With a finger over the hole it won't slide down, but drops out easily.
I wonder since it's inside the top, if it's not cooled enough.
I even added a little water to help cool.
I've done the displacer 3 times finally ended up
with one full of green foam. Maybe it's too heavy. The pictures are at the end of the video.
Maybe the whole rotating mass is too much weight.
It's fairly well balanced.
I redid the hole for the displacer rod, it's a slip fit. (string wouldn't work)
Maybe some one could look at the video and point to the right direction.
Thanks Pat
If the hammer didn't work
you have an electrical problem

Ian S C
Posts: 2221
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: looking for some advice on 1st engine

Post by Ian S C » Sat Jun 01, 2013 3:39 am

Hi Pat, I'm not an expert on tin can motors, but I'll see if I can help. Displacer, does the foam withstand the heat? It should not touch the sides. The wire coming out of the can should have a joint, so that the displacer stays straight, while the con rod moves sideways.
Are you trying to start the motor in the right direction, the displacer should lead the power piston by 90*.
I'll have another look at the video on Monday when I can get on broadband(on dial up now).
These motors can sometimes take a while to get going, keep at it. Ian S C

Junkie
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Location: England
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Re: looking for some advice on 1st engine

Post by Junkie » Sat Jun 01, 2013 5:49 am

So far as I can tell it looks as though the hole where the displacer rod enters the can is much to big.
Is there any kind of bushing around the displacer rod ? I can't see one in the video, although it isn't
perfectly clear.

As well as that, there's no bendable linkage between the displacer rod and the crankshaft,
so it's wobbling quite a lot, and probably creating quite a lot of friction as well as continuously
widening the hole where the displacer rod enters the can. You can get away without the bearing
in the displacer rod linkage, but the wire has to be very thin.

Hope that helps,
http://www.scraptopower.co.uk My web site, Stirling engines and AE stuff.

tapkoote
Posts: 13
Joined: Fri May 17, 2013 12:04 pm
Location: Washington State USA

Re: looking for some advice on 1st engine

Post by tapkoote » Sat Jun 01, 2013 10:06 am

Thanks guys
This version has no linkage in the displacer rod.
So it's swing like a pendulum. On the long version of the vid
the camera picked up a clicking noise I couldn't hear.
I put the can to my ear and could hear the piston scraping the side. ::eek:
I'm going for a lighter displacer w/linkage.
Back to work.
Pat
PS the displacer hole has a repair on the bottom
no gland
If the hammer didn't work
you have an electrical problem

fullofhotair
Posts: 265
Joined: Sun Aug 05, 2012 6:28 am

Re: looking for some advice on 1st engine

Post by fullofhotair » Sat Jun 01, 2013 11:41 pm

After the engine heats up there should be resistance when you turn it over. Similar to a lawn mower when you pull the rope. Your engine shows no compression resistance. The engine just spins freely. You have an air leak .Soapy water is a good way to find the leak. Just don't heat it up to run after you find the leak(air bubbles).If it sucked in water ,steam buildup will blowup your engine .So let it dry out.

Ian S C
Posts: 2221
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: looking for some advice on 1st engine

Post by Ian S C » Sun Jun 02, 2013 1:51 am

The displacer rod should be fitted through a a bush of some sort, a bit of brass tube, or a brass bolt with a hole drill down its length. The original motor had, I think a string of some sort, maybe nylon fishing line. As I said before, and others have said, the wire must have a joint. Get that sorted, report back, and if it does not go, we can have another look at it. Ian S C

tapkoote
Posts: 13
Joined: Fri May 17, 2013 12:04 pm
Location: Washington State USA

Re: looking for some advice on 1st engine

Post by tapkoote » Tue Jun 25, 2013 12:23 pm

Just an update
The rod one the displacer was leaking , tried a brass bush, no luck.
I think this type engine needs thin wire of fish line.
I put it aside, I've got other things to finish.
When i start again, I'll use darryl Boyd's plans for the beam engine.
Thanks for the help guys.
Pat
If the hammer didn't work
you have an electrical problem

Ian S C
Posts: 2221
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: looking for some advice on 1st engine

Post by Ian S C » Wed Jun 26, 2013 3:57 am

Hi Pat, perhaps you need a bigger hammer :laugh: Come back with your next attempt, and we'll try and help.
Ian S C

vamoose
Posts: 275
Joined: Tue Jul 03, 2012 12:16 am
Location: Australia

Re: looking for some advice on 1st engine

Post by vamoose » Wed Jun 26, 2013 4:53 am

There is a hammer at my work that you can borrow,
We call him "Mr Painless"

Image

He is mighty persuasive..
vamoose

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