Author Topic: Robinson Hot Air Engine.  (Read 85910 times)

Offline Dean W

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Re: Robinson Hot Air Engine.
« Reply #50 on: November 10, 2010, 07:23:09 PM »
Ran quite well in the second vid, David.  Nice and smooth.  The first vid kind of made me smile.  Not laughing at you,
but at the stirling engine that gave off an exhaust gas cloud! 
Dean W.

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Offline Bogstandard

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Re: Robinson Hot Air Engine.
« Reply #51 on: November 11, 2010, 02:39:57 AM »
David,

I don't know much about this type of Stirling engine, but could you rig up an external 'tin can' radiator to keep it well supplied with cooling water. It could be a semi sealed system, with only the tin can having an open top.

The circulation should be automatic, by convection.

I have shown the water level as being below the top plate, but if it didn't caused any internal engine leaks, it could be above.


John
« Last Edit: November 11, 2010, 02:41:41 AM by bogstandard »
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Offline madjackghengis

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Re: Robinson Hot Air Engine.
« Reply #52 on: November 11, 2010, 10:16:11 AM »
Hi David, in watching your two videos, I've concluded I will have to end up duplicating that engine sometime in the not too distant future.  As you, I like an engine that does something interesting and that one is among the more interesting I've seen and makes a fine "table engine", even a wife could find acceptable, maybe.  I hope to see it running with coolant soon, and the system closed up properly as it was originally intended to.  I expect you will get a bit more speed, and a bit more longer running that way, and it will be worth the extra work to set it all to right I expect.  Very well done. :thumbup: mad jack

Offline Stilldrillin

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Re: Robinson Hot Air Engine.
« Reply #53 on: November 11, 2010, 03:49:35 PM »
Thanks for all your comments Chaps!  :thumbup:

Stripped it again, this afternoon.
The only problem with a forum, your failures are public, as well as occasional triumphs.  :doh:

John, that is the way I intend to cool it. When/ if I get it sorted......   ::)

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline Bogstandard

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Re: Robinson Hot Air Engine.
« Reply #54 on: November 11, 2010, 04:06:04 PM »
Forget the failures David. We can't have perfection all the time.

It is the doing that counts.

John
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Offline Stilldrillin

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Re: Robinson Hot Air Engine.
« Reply #55 on: November 12, 2010, 12:20:05 PM »
Bitten the bullet!  ::)

Screwed a piece of screwed rod into my carefully tapped plug threads. Gripped in the vice, and beat L out of it with me lead tup....  :thumbup:

The ring had a drill dimple/ false start at it's inner edge. Got a blade under and levered it out....  :thumbup: (again).





Now, we're at rock bottom..... The only way is up, perhaps!

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline madjackghengis

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Re: Robinson Hot Air Engine.
« Reply #56 on: November 12, 2010, 12:34:05 PM »
Hi David, it looks like you've got to the bottom of all of it, and now there is no way but up.  I expect you will have a much better running engine now that you are fixing it from before the screwup of the previous owner, and not having to contend with his errors any more.  It's good to see the pipe removed, and the prospect of having a fully sealed system allowing full cooling, and full engine pressure.  Sometimes there's just no substitute for a heavy hammer well applied. :poke: :bugeye: Looking forward to the return of the parts properly, to their appropriate place, and the video of it running like a scalded dog.  :lol: mad jack

Offline Bluechip

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Re: Robinson Hot Air Engine.
« Reply #57 on: November 12, 2010, 12:37:56 PM »
Well Done that man ....  :thumbup:  :thumbup:

I had every confidence in you ...

Onward and Upward ...

Dave BC
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline sbwhart

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Re: Robinson Hot Air Engine.
« Reply #58 on: November 12, 2010, 02:55:18 PM »
Well Done Dave

You can't beat a good wellying wif a big ammer.

Now you'll get it sorted proper.

Stew
« Last Edit: November 12, 2010, 05:16:59 PM by sbwhart »
A little bit of clearance never got in the road
 :wave:

Location:- Crewe Cheshire

Offline Dean W

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Re: Robinson Hot Air Engine.
« Reply #59 on: November 12, 2010, 06:21:50 PM »
There ya go, David.  "Don't force it... just get a bigger hammer!"
And, "If it ain't broke, you're not hitting it hard enough".
Dean W.

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Offline NickG

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Re: Robinson Hot Air Engine.
« Reply #60 on: November 12, 2010, 06:24:04 PM »
Well done David, now just don't try taking it to bits any further now  :lol:

You'll definitely sort it once and for all now, just like the builder should of. To be fair, I think he's done  a better job on it than I could though!

Nick
Location: County Durham (North East England)

Offline Stilldrillin

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Re: Robinson Hot Air Engine.
« Reply #61 on: November 15, 2010, 03:49:11 PM »
Well, the ascent has started.  :thumbup:

Some months ago, I bought meself a couple of pieces of cast iron, 1 each, at a flea market. I was thinking flywheels, at the time. :scratch:

Looks just the ticket.....




Turned a spigot on both ends. Time to bore out......




Largest drill I've got, 16mm......




At knock off. After some time spent boring through at .020" a pass, the hole is now around 1"+.

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline shoey51

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Re: Robinson Hot Air Engine.
« Reply #62 on: November 16, 2010, 01:46:43 AM »
doing a grand job there mate keep up the great work :clap:

Offline Stilldrillin

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Re: Robinson Hot Air Engine.
« Reply #63 on: November 16, 2010, 12:40:29 PM »
Thanks Graham!  :thumbup:

Three sessions today..... Had to keep resting the motor, as I could smell hot paint, or summat!  ::)

This project has made me realise the pifflin' power output of a 7x12.

Started off at 20thou passes. Finished, only just managing to pull 10thou, though things were a little hot......  :bugeye:




Got the bore roughed, 2.25 (-1/32")




Hope the o/d is a little easier. Don't like overloading things!


David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline Bluechip

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Re: Robinson Hot Air Engine.
« Reply #64 on: November 16, 2010, 02:00:29 PM »
Dave

Oooh Dear .... you might do well to strip that motor   :(

Is it anything like 600w as per a Chester Conquest (20?) Mill, 'cos someone I know had a stinky motor after being used a lot on one of those, and we just saved it I think.

Briefly, he said the motor pongs and it's a bit stiff to turn, but it does turn. Not the mill spindle, 'cos it turns freely in neutral.
Not good sez I.
You may have got it so hot that it's taken up the end clearance on the armature. Give it a good hour or so to cool, see if it's freed off.
No, did not.
Will it free with use ?
No. Take it off. See whats really happened.

Some little black bits fell out, what are they?
Dunno. but not normal. Leccy motors never need a de-coke...

OK. Strip it. Take the brushes out. Remove the tie bolts.

It appears that there is some soft white jollop to take up clearance in the winding slots. This had got hot, melted, and run between the magnets and armature. There to carbonise with friction.

So, told him to very carefully remove any white bits that looked out of place, clean out the motor , re-assemble and give it a go.

Success. Motor free ..

Just tried to phone him, but he's away in Denmark. But his wife says she thinks 'he fixed the motor, and it's still OK'

He ??? I spent about 2 hrs on the phone, and sent some 5 e-mails with sketches ... spoon feeding the twerp ... Grrrrrr


May not be any relevance to your motor Dave, but ... if it saves one ..

Dave BC












« Last Edit: November 16, 2010, 02:08:50 PM by Bluechip »
I have a few modest talents. Knowing what I'm doing isn't one of them.

Offline Bogstandard

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Re: Robinson Hot Air Engine.
« Reply #65 on: November 16, 2010, 02:46:31 PM »
For goodness sake Stilldave, if it starts smoking, grab the vacuum and suck up all the smoke and save it in a jar. If you lose that, you will never get the motor running again.

Bogs

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Offline NickG

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Re: Robinson Hot Air Engine.
« Reply #66 on: November 16, 2010, 03:33:30 PM »
For goodness sake Stilldave, if it starts smoking, grab the vacuum and suck up all the smoke and save it in a jar. If you lose that, you will never get the motor running again.

Bogs



 :lol:

I'm surprised you managed to drill 16mm to be honest!  Good work David, what's going to be different between this and the old one and how are you going to make the flange?

Nick
Location: County Durham (North East England)

Offline Stilldrillin

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Re: Robinson Hot Air Engine.
« Reply #67 on: November 16, 2010, 04:01:29 PM »
Dave, John.
Thanks for the concern, and smiles Lads!  :thumbup: :clap:

I don't think there will be a problem..... Probably!  ::)

Frankly, it smelt of hot paint after some 15 mins of ploughing. So, each time, I went and did something else for an hour or so.

At knock off, I shovelled out the black dust, and oiled round. Realised the headstock wasn't even aired, so I nipped the taper bearings a little, then ran it free for a few mins.

All ok, I reckon!  :thumbup:


Nick.
Essentially, I intend to face off the 6BA screw holes, including the part thread. Reduce the wall thickness by half, back to the neck, behind the small dia cover flange.

The counter bored new piece will slip over, held with some high temp sleeve lock, now on it's way from America.

I will then bore and turn to correct dimensions, with a larger dia cover plate flange, fitting into a thicker (3mm) steel cover plate. (Cos that area leaked as well).


Well..... That's the plan...... Probably!  :scratch:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline NickG

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Re: Robinson Hot Air Engine.
« Reply #68 on: November 16, 2010, 04:05:45 PM »
Ahh, I see now... good plan, I think  :scratch:  :lol:

Nick
Location: County Durham (North East England)

Offline sbwhart

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Re: Robinson Hot Air Engine.
« Reply #69 on: November 17, 2010, 01:47:28 AM »
Looks like you've bin whipping them horses Dave

 :whip: :whip: :whip: :whip: :whip:

You can't beat making your kit work for a living.

Fix looks good.

Stew

A little bit of clearance never got in the road
 :wave:

Location:- Crewe Cheshire

Offline shoey51

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Re: Robinson Hot Air Engine.
« Reply #70 on: November 19, 2010, 02:01:23 PM »
Looks like you've bin whipping them horses Dave

 :whip: :whip: :whip: :whip: :whip:

You can't beat making your kit work for a living.

Fix looks good.

Stew



im still confused but thats me generaly  :scratch: :coffee:

Offline Stilldrillin

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Re: Robinson Hot Air Engine.
« Reply #71 on: November 19, 2010, 03:59:27 PM »
You're confused Graham??  

By 'ek lad...... Yer aught to try it from up close & personal!  :scratch:


No machining time today, but got a few minutes to sort through the box of parts... The bloody displacer is wobbling on it's shaft!! :bugeye: :bang: :bang:

The silver soldering has let go! It's only been in the box with the other parts....... Sigh........

Still, I've got all winter to sort it. And, I guess that will open up a new discussion on how to make the best displacer.  :thumbup:

David D
David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!

Offline Bogstandard

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Re: Robinson Hot Air Engine.
« Reply #72 on: November 20, 2010, 12:48:22 AM »
Dave,

I know exactly how you are feeling.

I used to restore or fix badly made or worn out engines, and things made by other people never seem to come up to your own expectations of how it should be done.

I think in your case, by the amount of fiddling and tweaking you have had to do, it would have been easier to make one from scratch.


John
If you don't try it, you will never know if you can do it.

Location - Crewe, Cheshire

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Offline madjackghengis

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Re: Robinson Hot Air Engine.
« Reply #73 on: November 20, 2010, 09:24:28 AM »
Hi Dave, I'm not confused, just seeing what I'm used to seeing in my own shop, in someone else's :bang:  Being on medical retirement from the Marines, I tend to be the recipient of other's junk and garage clean out, as that tends to be in my price range.  I think you're idea will work fine, I know you'll get a much better performance when the parts are all up to your own standards, and until then, you won't be happy.  Given you're going to have to do something with the displacer, I'd recommend you use a stainless steel can for it, if you can find one that is a fairly close fit, with little excess space.  I've got two cans I cut out of used fuel filters for fuel injected cars with the medium pressure pump in the tank, requiring sturdy filters in between.  Right now, I haven't found the suitable sized container/body to run them in, but if you go to a repair shop, it's quite possible you can find a filter can that matches your diplacer cylinder bore minus the necessary clearance, in their trash can.  Both my cans came out of cars I had to replace the filter in.  I'm looking for a tempered glass chamber close to the size, so the displacer can be watched, but that's a different story.  The less heat the can conducts north, the more efficient the displacer acts in its part of the whole heat cycle, and a brass one conducts too much heat if you can find a replacement.
   All that cast iron work looks good, and I like the fact you're doing a bang up job of cleaning up a mess left by someone else, and think it will make a great improvement in your engine, and won't be a niggling thing left in the back of your mind all the time.  As you can probably tell, I wish very much that had happened to be left on my own doorstep, but I won't be greedy.  It's enough to see you doing the good job.  Now I'm really looking forward to seeing it finished and running. I've copied pictures so I can try to fabricate something that cobles together to look close enough to get the cast iron charm and antique look that engine has.  If you needed to, you could even take a sheet of stainless steel ten or fifteen thousandths thick, roll it in a tube and silver solder it, and solder a top and bottom to it, to get a right sized can if you can't find one.  What's the actual i.d. of the dispacer bore, if you don't mind my asking?  I might be able to find something of the right size and either send you one, or send you looking in the right place to find one.  I'd be right proud to help a cousin across the pond, particularly one who has done such careful work on a cock up. :nrocks:  It'd be the least I could do, frankly. :headbang: mad jack

Offline Stilldrillin

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Re: Robinson Hot Air Engine.
« Reply #74 on: November 20, 2010, 12:34:43 PM »

Dave,
I know exactly how you are feeling.

I used to restore or fix badly made or worn out engines, and things made by other people never seem to come up to your own expectations of how it should be done.

I think in your case, by the amount of fiddling and tweaking you have had to do, it would have been easier to make one from scratch.
John

Yer right John!
But, where would be the fun in that? I've always enjoyed "sorting things out", if I could......  :smart:

I am having fun..... Aren't I?   :thumbup:

Am I?  :scratch:

David D


David.

Still drilling holes... Sometimes, in the right place!

Still modifying bits of metal... Occasionally, making an improvement!