Author Topic: Model Heinrici Engine  (Read 9001 times)

Online Jo

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Re: Model Henirici Engine
« Reply #15 on: November 08, 2020, 07:29:27 PM »
This model is based on an original Heinrici engine which was owned by Mr H. A Taylor that was used to drive a roots blower for a petrol-air gas generator.

The engine was lost in September 1941 when the ME offices in Kingsway were bombed. However before this happened the engine was drawn up and the blue prints were later published in Model Engineer in Volume 83 (I do not have a copy of these  :wallbang: ) This original design of the Heinrici engine was mostly made of cast Iron and is still available from Reeves in the UK.

In 1964  :NotWorthy: Mr Edgar Westbury took the earlier design and modified it to make it easier to machine and so that the model makers could use Aluminium alloy that they could cast themselves in their back gardens. Aluminium was used for all the main parts except the working cylinders, where sliding wear is involved. Mr Westbury also modified some of the parts to make them easier to machine for the home machinist, while keeping the visual appearance of the engine. The Alyn Foundry castings for this model are thus true to Mr Westbury's intention for this later model in that it is made of Aluminium :)

Jo
« Last Edit: November 08, 2020, 09:19:32 PM by Jo »
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Offline Dave Otto

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Re: Model Henirici Engine
« Reply #16 on: November 08, 2020, 07:39:53 PM »
Thanks Jo

So if I understand correctly both your model and the Westbury one are from the same original engine? My castings are all iron except for the water jacket; the stand is fabricated from sheet steel.
It is still interesting me that you never see a photo of this style engine, i.e. Alpha style with a square water jacket;  if anyone has a link to one I would love to see it?
I purchased my castings from a friend many years ago, I'm not sure where he got them.

Dave

Online Jasonb

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Re: Model Henirici Engine
« Reply #17 on: November 08, 2020, 07:55:07 PM »
I think the square hopper ones are known as the "HA" type, see this one on Smokstak

https://www.smokstak.com/forum/threads/heinrici-hot-air-engines.160400/

Looks like Jo will be needing to stick some alphabetti spaghetti to here hopper. Also looks like it may have screws retaining the cylinder
« Last Edit: November 08, 2020, 07:59:57 PM by Jasonb »

Online Jo

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Offline Bob

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Re: Model Henirici Engine
« Reply #19 on: November 08, 2020, 08:02:58 PM »
This is a very interesting engine. Gerd Maier has very extensive documentation on Heinrici engines and thinks that Heinrici did not make any engines with square section cooling chambers as features in the Westbury engine. Gerd suggests that "A front view and a side view are not sufficient to determine the shape of an object; a top view is required to define if this body is round or square. It was in the 1990s when Heinrici two-cylinder «copies» (I call them «fakes») were made by the dozen in a small workshop in Southern England. I suppose that they were following the two drawings reprinted above. These were made by Edgar T. Westbury, based on an original 1.18" watercooled «HA» model lost during the war. Since there was no plan view, copies with an asymmetric and square engine baseplate (instead of a round one) were produced. Moreover, instead of the maker's name embossed on the cooling-jacket a square plaque HEINRICI /MOTOR was bolted onto an inappropriate cast-iron HL-type base. Other copies, embossed SCHURAT, are known" To quote from Gerd's CD on Heinrici prototypes.

I have always thought it a bit odd as at first glance it has the form of Heinrici's concentric (beta configuration) engines but it is in fact a gamma configuration engine. There seems to be a gap in the market for a medium size model of a Heinrici concentric engine that is somewhat closer to the prototype then ETW's engine.

Bob

Online Jasonb

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Re: Model Henirici Engine
« Reply #20 on: November 08, 2020, 08:12:06 PM »
I'm tempted to get the drawings for this one, he does not sell the castings anymore but drawings are supposed to be available

http://www.de.heinrici-heissluftmotor.de/assets/applets/Seiten_aus_mim_05_08.pdf

Online Jo

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Re: Model Henirici Engine
« Reply #21 on: November 08, 2020, 08:43:33 PM »
Since there was no plan view, copies with an asymmetric and square engine baseplate (instead of a round one) were produced.

There is a plan view but of course there is a platform above the cooling jacket which the two A frames mount onto so unless the shape was shown as hidden detail the fact it should have been round would have been lost. A round jacket could be turned up out of a piece of square Ali and the Water pipe bosses added after.

Jo
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Online Jasonb

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Re: Model Henirici Engine
« Reply #22 on: November 08, 2020, 08:47:18 PM »
Strange that the Smokstak link I posted is by Gerd where he shows a square HA yet the copied text by Bob seems to contradict that?

Gerd's website http://www.stirlingmaier.com/dcomp.htm

Offline Dave Otto

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Re: Model Heinrici Engine
« Reply #23 on: November 09, 2020, 12:35:23 AM »
Thanks for all the information guys, interesting topic.
Bob, I guess I have my alpha and gamma engine configuration backwards.

Dave

Online Jo

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Re: Model Heinrici Engine
« Reply #24 on: November 09, 2020, 10:08:17 AM »
Having reviewed the cooling jacket casting this morning I can confirm that the core is circular rather than as I feared square. This means that it would be possible to machine the jacket round if sufficient information was available to be able to define the correct shape (diameter and the water bosses).

Because the jacket is separate from the base it would still need a square flange at the bottom which would correspond with the raised square area on the platform in order to bolt it down. A square flange at the top could be left to bolt the cover and the A frames down to it.

Jo
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Online Jasonb

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Re: Model Heinrici Engine
« Reply #25 on: November 09, 2020, 10:28:36 AM »
If you went with a round jacket would you also go for a completely different stand? Looking at the line up Dave posted yesterday the only one with the cylinder at the side is the smallest and that has a different type of stand, unless an image can be found of one with the square stand.

Do we know if Westbury made it to a specific scale or is it 1:1 ? what is the bore of his?

Online Jo

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Re: Model Heinrici Engine
« Reply #26 on: November 09, 2020, 11:09:20 AM »
I am not currently intending on rounding the jacket as I believe Andy Spooner would have aimed to make a good reproduction as he was a collector of Stirling Engines. The fact that Andy put so much time and trouble into the patterns/cores for the base tells me he was determined to get that right so there is no reason to assume any of the remainder is wrong.

Do we know if Westbury made it to a specific scale or is it 1:1 ? what is the bore of his?

It is full sized: it has a 30mm bore same as the original Heinrici engine.

Jo
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Offline Alyn Foundry

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Re: Model Heinrici Engine
« Reply #27 on: November 09, 2020, 11:29:22 AM »
Good morning All.

I'm attempting to contact Andy later as an old collector friend is still in touch. We might as well get it from the " horses mouth " so to speak.

Cheers Graham.

PS. This photo is from a Dutch collector who recently posted it on the Small power ( Facebook ) engine group.
« Last Edit: November 09, 2020, 11:32:49 AM by Alyn Foundry »

Online Jo

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Re: Model Heinrici Engine
« Reply #28 on: November 09, 2020, 12:23:33 PM »
If you are talking to Andy, Graham maybe you could see if he would tell you the history of this set of his/your castings. I would also like to know how well his ran with the Ali flywheels. And if he has a pic of his original that would be the icing on the cake  :embarassed:

Jo
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Offline Bob

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Re: Model Heinrici Engine
« Reply #29 on: November 09, 2020, 05:07:01 PM »
Hi Dave

People get quite confused by the alpha, beta and gamma configurations of Stirling engines. I am not sure if the terminology is very helpful but I suppose using Greek letters adds an air of academic respectability. The gamma configuration has separate power cylinder and displacer chamber that are linked by a tube. This configuration gives a lot of flexibility for the linkage so for example the power cylinder and the displacer chamber can be at 90 degrees to one another and both work from a single crank pin (As the Stirling 90 described by Anthony Mount in Historic Engines worth Modelling Vol 1) or the two chambers can be parallel to one another and the linkage uses two crank pins 90 degrees apart (Typical of Heinrici HA) or by the use of a bell crank linkage (as used by T E Haynes in his engine described in Model Engineering for Schools Book 2 Incidentally this engine has been described by others  in the model engineering world but without giving Mr Haynes his due recognition) The downside of the gamma configuration is the dead space due to the air in the transfer pipe and possible restriction of the pressure pulse between the displacer chamber where it is generated and the power cylinder.

The beta configuration has the power cylinder coaxial with the displacer chamber and in the best designs the stroke of the power piston overlaps with the swept volume of the displacer. There are lots of engines that work like this such as the Rider Ericsson pumping engine and the Heinrici HL type. From my observations at Stirling rallies and exhibition stands beta engines outperform gamma engines and I have always attributed this to the reduction in dead volume and the free flow of air between the working cylinder in the displacer chamber.

The enigma is the alpha engine. These should be the best engines in terms of specific power output and the ones that have been well documented do indeed run very well and produce a lot of power for their size. That being the case why in over 10 years of exhibiting Stirling engines at model engineering shows and rallies have I only ever seen one alpha engine running? The alpha has two pistons set 90 degrees apart and the cylinders are connected by a transfer pipe that often incorporates a regenerator. In full size the Haywood Tyler engine is an example of an alpha engine. I suspect some Haywood Tyler models are actually gamma configuration engines rather than true alpha engines.

Rather contentiously, is an alpha engine just a gamma engine with a big fat displacer rod the same diameter as the bore of the displacer chamber??

Bob