Author Topic: Our Heinrici resto….  (Read 914 times)

Offline Alyn Foundry

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Re: Our Heinrici resto….
« Reply #15 on: December 28, 2022, 12:18:10 PM »
To conclude this article.

I know there have been many failures with this engine over the years but a couple of modifications can make a mountain of difference. If any readers are contemplating a build, don’t hesitate, go for it…. The castings are available from Reeves of Birmingham.

Find a suitable aerosol deodorant can to make the displacer piston from. Either Steel or Aluminium. The Steel is much slower in heat conduction but a little heavier in weight. The hot end material chosen is the other major factor. In the original ME text it suggests Copper or Nickel alloy. Both these are good conductors of heat, sadly in the wrong direction. We need a concentrated spot, right at the bottom end but with poor conduction via the material. As stated above worn out shock absorbers make ideal hot ends with no risk of leaking air.

There’s two methods of fixing the hot end described in the ME text. The screw on method is the least desirable. Any heat will be directly conducted into the cold end. The use of a flange with studs and nuts with a nice thick juicy Silicone or Viton O ring between will greatly reduce heat transfer. And why so many studs, in the original text? I would suggest a maximum of 3, the smaller the better. It’s not a racing engine, an injured Gnat develops more power. No need for all those extra fixtures.

Many of the smaller, original Heinrici engines were actually air cooled. The cold end being just a tubular Iron casting. They worked very well. Because the replica cold end is made from Aluminium it will tend to absorb heat much more quickly so this is why a water jacket is essential.

 :cheers:  Graham.

Offline Jasonb

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Re: Our Heinrici resto….
« Reply #16 on: December 28, 2022, 01:11:37 PM »
Graham, what would you suggest for the likes of Dave who have an all aluminium cylinder? I would be inclined to bore it out an fit an iron one much like the current offering from Reeves combined with a lapped iron piston.

Interesting thought about the screwed attachment as I think the original engines used a threaded flange, concentric ones certainly did.

Offline Alyn Foundry

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Re: Our Heinrici resto….
« Reply #17 on: December 28, 2022, 01:40:54 PM »
Graham, what would you suggest for the likes of Dave who have an all aluminium cylinder? I would be inclined to bore it out an fit an iron one much like the current offering from Reeves combined with a lapped iron piston.

Interesting thought about the screwed attachment as I think the original engines used a threaded flange, concentric ones certainly did.

It was me that started that confusion Jason. Dave does have all the components in Iron, apart from the cold end.
If the power cylinder had been done in Aluminium then yes, I would definitely sleeve it and lap finish. The cold end doesn’t need any fastidious work as it’s a clearance fit to the displacer piston.

The real problem is stopping the heat being transferred up to the cold end and this is why I suggested the stud and nut method. With a decent gasket between the two halves the heat can only travel through the fixings.

 :cheers:  Graham.

Offline Admiral_dk

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Re: Our Heinrici resto….
« Reply #18 on: December 28, 2022, 05:16:19 PM »
OK - so it is an photo illiusion that made me think it was much bigger  ;D

I suggest using Stainless-Steel for the Studs - as it is a poor heat-conductor .... unless someone claims that this will result in corrosion of the other parts ....

Per

Offline scalemodel

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Re: Our Heinrici resto….
« Reply #19 on: December 28, 2022, 07:37:27 PM »
You made a lovely job of that graham I know where to come when I can't get my rider running lol

Jonathan

Offline Brendon M

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Re: Our Heinrici resto….
« Reply #20 on: December 29, 2022, 12:46:37 AM »
Great engine, thank you for sharing :)
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Offline Alyn Foundry

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Re: Our Heinrici resto….
« Reply #21 on: December 29, 2022, 02:02:34 PM »
8)

Must find some time to have another flick over of mine  :-X

Jo

Indeed you should Jo….

Here’s a link to your thread.  https://www.modelenginemaker.com/index.php/topic,10005.0.html

Blimey 2 years ago now. :o

Having re read, you left it after finding the air leak between system and cooling water. Did you try to fix the problem at all?

These engines are amongst the safest to play with IMO even solo. I’m looking forward to the conclusion.

 :cheers:  Graham.

 

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