Author Topic: Rocker V Stirling Engine  (Read 9043 times)

Offline Ian S C

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Re: Rocker V Stirling Engine
« Reply #30 on: October 11, 2017, 03:48:08 AM »
You could drop an e-mail to Andy Ross in the states, he's been there and done that as far as coatings and anodizing of cylinders and pistons.
I just keep away from aluminium on these parts, and try to stick to cast iron for both bore and piston, although if the size is right I use the tube from inside a shock absorber, because this is round, parallel, and highly polished.
Ian S C

Offline Plani

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Re: Rocker V Stirling Engine
« Reply #31 on: October 11, 2017, 08:13:29 PM »
Thank you for the input Pete. I'm aware or this fact, actually I had to specify the thickness of the oxide layer (in micrometers :o) to the company who is doing this. So I think this will be done quite accurately. And also for this reason I will fit the piston to the cylinder, so it doesn't really matter if the bore is a little bit smaller.

Ian, I was in touch with  Andy Ross. He provided the articles he wrote about these engines.

Plani

Online 10KPete

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Re: Rocker V Stirling Engine
« Reply #32 on: October 11, 2017, 10:48:36 PM »
 :ThumbsUp: :ThumbsUp:

Pete
Craftsman, Tinkerer, Curious Person.
Retired, finally!
SB 10K lathe, Benchmaster mill. And stuff.

Offline Plani

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Re: Rocker V Stirling Engine
« Reply #33 on: October 24, 2017, 02:23:00 PM »
This time I made the ring to which the hot cap will be soldered later.

Some mild steel was faced and drilled:


The hole was then opened up, including the step for the hot cap:


Then the other side was faced and the diameter turned as well as a groove for the O-ring:


Finally the part was taken to the mill to drill the holes for the bolts:


Done:


Plani
« Last Edit: May 02, 2018, 06:01:03 AM by Plani »

Offline Plani

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Re: Rocker V Stirling Engine
« Reply #34 on: November 04, 2017, 04:24:09 PM »
Just a very brief update. That's what the cylinder looks like hard coat anodized. I actually think, it looks ok.


Plani
« Last Edit: May 02, 2018, 06:01:20 AM by Plani »

Offline b.lindsey

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Re: Rocker V Stirling Engine
« Reply #35 on: November 04, 2017, 05:01:49 PM »
Looks cert good to me plani. Did you have it done commercially?

Bill

Offline crueby

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Re: Rocker V Stirling Engine
« Reply #36 on: November 04, 2017, 05:27:44 PM »
That looks fantastic. Does the anodizing hold up on the interior of the cylinder okay? (is that the 'hard coat' part of the name? )

Offline Plani

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Re: Rocker V Stirling Engine
« Reply #37 on: November 05, 2017, 08:43:58 AM »
Bill, as far as I know there are some nasty chemicals involved in this process as well as very high electrical currents. Therefore I had the anodizing done by a specalized company.

crueby, time will tell....although I'm optimistic since half of the aluminum oxide layer grows into the surface and the other half is added on top of the surface. So this should hold up quite well. But we will see once the engine is running...

Plani

Offline yogi

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Re: Rocker V Stirling Engine
« Reply #38 on: November 05, 2017, 09:10:23 PM »
Beautiful looking part Plani!!!  :ThumbsUp: :ThumbsUp: :ThumbsUp:

Offline Plani

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Re: Rocker V Stirling Engine
« Reply #39 on: December 17, 2017, 04:39:02 PM »
Thank you Yogi  :cheers:

With the cylinders finished I could now move on to the Pistons. I usually do it in this order, because it's easier to fit the piston to the cylinder than the other way around.
The compression piston on this engine consists of three parts. I started with the body of the piston:


After turning the first side, the part was left on the stock and a slot was cut for the bell crank:


Then the first side was faced, the hole for the pin was drilled and reamed and the outer contour was milled:


In order to get the second side square to the others, a parallel was stuck into the slot and indicated:


The part was then cut off the stock and the second side was machined using a square collet:


Piston body completed:


To hold the lip seal on the body a disc was turned:


Then the lip seal was made. For this I used IGUS W300 which is a plastic bearing material which is supposed to have a little coefficient of friction and also little wear:


I first turned the outside diameter of the seal cylindrical and 0.05mm bigger than the bore. Then a 8 taper was machined on the inside and the outside with a wall thickness of 0.25mm. And finally the seal was parted off:


The assembled compression Piston:


By sticking it into the cylinder and moving it by hand, it seems to be a little "stiff". Maybe the 0.05mm oversize was a bit much. I will reevaluate this once the whole mechanism is in place an I can see how it runs.

Plani
« Last Edit: May 02, 2018, 06:02:17 AM by Plani »

Offline yogi

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Re: Rocker V Stirling Engine
« Reply #40 on: December 20, 2017, 04:12:52 AM »
Fascinating!!!
This is so cool! Looking forward to see your next installment...  :ThumbsUp: :ThumbsUp: :ThumbsUp:

Offline b.lindsey

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Re: Rocker V Stirling Engine
« Reply #41 on: December 20, 2017, 11:56:05 AM »
Still following along as well Plani. The piston assembly looks great  :ThumbsUp:

Bill

Offline Plani

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Re: Rocker V Stirling Engine
« Reply #42 on: January 10, 2018, 08:21:53 PM »
Thank you for the kind comments Yogi and Bill  :cheers:

Next I made the bearing posts. Therefore some aluminum stock was cut off:


The parts were milled to a T-shape:


Then the inner contour was milled:


And finally the parts were bolted to some scrap aluminum bar to mill the outer contour:


Done:


Plani
« Last Edit: May 02, 2018, 06:02:52 AM by Plani »

Offline PJPickard

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Re: Rocker V Stirling Engine
« Reply #43 on: January 11, 2018, 10:54:15 AM »
Excellent work on this and yes Mr. Ross knows his Stirling engines! He has a couple on youtube that I would love to get the plans for.

Offline Perry

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Re: Rocker V Stirling Engine
« Reply #44 on: January 13, 2018, 08:31:45 PM »
Very interesting engine and build log, I especially like the lip seal type piston. Lots of inspiration  :ThumbsUp: