This article is based on an email conversation with This email address is being protected from spambots. You need JavaScript enabled to view it.">Brad Soward who was answering a series of questions sent to me from This email address is being protected from spambots. You need JavaScript enabled to view it.">Andrew Alkemade. The words are Andrew's and Brad's. The photos of Andrew's engine are his, and the photos of the engine at Brad's place are mine. Andrew and Brad have both given their permission to reproduce their discussion in the interest of helping other Heinrici restorers.

Andew's words and pictures are © Copyright 2003 Andrew Alkemade
Brad's words are © Copyright 2003 Brad Soward
My pictures are © Copyright 2003 Paul Pavlinovich

Andrew's request for assistance...

Paul
Hope you can help.

I have a Heinrici motor that was passed down by my father and his father.  The motor was used in a mineral water bottling operation that the Alkemade family ran around WW1.

The motor I have is a later model with a 2" bore and central displacer. (see photos).
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I am very interested in talking with anyone that has one as mine has a problem which I would dearly like to fix.

As it was missing its original stand it had never been used to my knowledge until a few weeks ago when I finally got around to building one and got hold of an old kero blow lamp as a heat source.

After a 5 mins or so after a far bit of oil and assistance it finally started to run by itself. It lasted about 5 mins and started to slow down then it stopped.

I found that the arm that works the central piston had come loose from it shaft. Looks as if the locating pin had sheared some time ago and the rust has started to let go. Tried to fix it by drilling out the pin but that was less than perfect.  It worked for a while and was particularly good one very cold night.  The first time it ran it was lucky to do 150 RPM but on that night was probably closer to 300.

Since then the pin has worked loose again and the timing has slipped significantly to a point where it will barely run. Before I dismantle it to rebuild the shaft and create further problems for myself I have few questions if you can point me to someone who can help.
  1. Heat source is the kero blow lamp a suitable heat source or is it likely to be too hot and do damage.  How important is the water cooling if running it for short periods
  2. Timing. Should the central arm work exactly in parallel with the external arm attached to the fly wheel or at some other orientation. Does anyone have a description of the timing between the mail piston and the central one.
  3. Oil..should normal engine oil be placed in the "petroleum" cylinder and is there any special operation of the internal rod. I presume it provides lubricant to the central piston and the main piston.
  4. If I dismantle the main piston is there any special tricks I need to be aware of.
  5. Are you aware of anyone close to Melbourne that has one on going condition that might be able to help.
Regards
Andrew.

Calling on the wealth of friends...

As I had very little knowledge about the Heinrici, but remembered seeing one at Brad Soward's house when I visited him in Nimbin only a few days before I forwarded Andew's message to Brad who was able to provide some assistance...

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Brad's reply...

G'day Andrew
Your message to Paul Pavlinovich has been forwarded on to me as I currently have a Heinrici style hot air engine here on loan. I am by no means an authority on these things, but I will try to help as best I can. The maker of this engine, while originally thought to be a genuine Heinrici, is now in some doubt and it is most likely some sort of copy. Its design follows the pattern of an early Heinrici Beta type fairly closely though, so I hope it will be close enough to be of help. There are two styles of these Heinrici, and from your description you appear to have one of the earlier types, made by Louis Heinrici between the 1880's and about 1920. They are distinguished by the displacer crank mechanism driven off the outside of one flywheel. Ernst Heinrici brought out an improved design around 1920 that used a compound crank and dispensed with the outside linkage. Moving on to your specific questions.

<As it was missing its original stand it had never been used to my knowledge until a few weeks ago when I finally got around to building one and got hold of an old kero blow lamp as a heat source.After a 5 mins or so after a far bit of oil and assistance it finally started to run by itself. It lasted about 5 mins and started to slow down then it stopped.>

Have you made sure that the hot and cold ends of the displacer cylinder are well insulated? The whole principle of these things relies on the difference in temperature of the two ends of this cylinder, so insulating them from each other and eliminating air leaks are crucial to getting good performance. On the engine I have here, which is larger than yours (103mm bore) the thermal barrier in the top of the stand is asbestos rope and fireclay about 30mm thick. Without something like this in place the metal
frame eventually heats throughout, equalizing the temperature, and the engine then stops and won't run until it all cools down again. It is absolutely essential that there are no air leaks and minimal friction as these atmospheric engines have a very low power output. Even using too heavy an oil can be enough to prevent them from running. :-( My little flame licker model can only use powdered graphite!

<It worked for a while and was particularly good one very cold night. The first time it ran it was lucky to do 150 RPM but on that night was probably closer to 300.>

This is a good demonstration of how the more temperature differential you can maintain, the more efficient the engine will be. This is the primary reason for the water cooling jacket. I have also played with a model Heinrici that is a little smaller than your engine and its cylinder was air cooled. Still worked well.

<Is the kero blow lamp a suitable heat source or is it likely to be too hot and do damage. How important is the water cooling if running it for short periods.>

Both the engines I have been exposed to use small LP gas burners in the base, and they both will operate quite well with the burners turned right down. I would be a little concerned with the blow lamp if the hot end of the displacer cylinder is brass, but if it is cast iron then it shouldn't do damage. What I would be more concerned with is heat soak, in that the blow lamp is probably heating up a lot more of the engine frame than it needs to or should. The more direct targeting of the small gas ring seems to be a
more efficient and easier solution. The larger engine I have here just has a small gas ring off a stove mounted in the base, while the one in the model is about the size of a small bunsen burner. Remember, the point of the exercise is to heat the parcel of air in the displacer cylinder, not the whole thing. I can run both engines with these turned down to the point of the flame being barely visible. Bigger flame = more rpm. As I run these all day at two day shows and I am not trying to drive anything with them, I can
live with a few less revs in the interests of fuel economy. A 2kg cylinder will run the model for about a week! :-)

<Timing..Should the central arm work exactly in parallel with the external arm attached to the fly wheel or at some other orientation. Does anyone have a description of the timing between the main piston and the central one.>

Now here is where I hope I will not give you a bum steer. The 'central piston' is known as the displacer piston, while the 'main' piston (the one at the top of the bore) is the power piston. In the engine I have here, the displacer 'leads' the power piston by 30 degrees and the displacer crankpin is 60 degrees 'ahead' of the big end. This figure can vary somewhat over different engine designs, so I hope this is somewhere near what you are looking at. The linkages for the displacer form a 'V' and are fixed about 20
degrees apart on the layshaft at the side. The 'hairpin' shaped connecting rod is attached to the power piston, with the displacer rod passing through the power piston in the middle. This displacer is a loose fit in the cylinder to allow the air to pass around it, while the power piston is an airtight fit in the cylinder and where the displacer rod passes through it.

<Oil...should normal engine oil be placed in the "petroleum" cylinder and is there any special operation of the internal rod. I presume it provides lubricant to the central piston and the main piston.>

I can't help you with this one as neither of the engines here have a 'petroleum cylinder'. Both use oiler cups on the big end and main bearings, with oil holes on all other moving linkages. The displacer piston does not need lubricating as it is not in contact with the cylinder walls. I just apply a little light machine oil, such as sewing machine oil, to the power piston bore and connecting rods before starting up.

<If I dismantle the main piston is there any special tricks I need to be aware of.>

Shouldn't be any tricks, other than to be careful to avoid damaging anything, particularly seals and sealing surfaces.

I hope this has been of some help to you and I wish you well with your project. I don't know if it will be any help, but there are some pictures of both these hot air engines on my Webshots site, which can be accessed by clicking on the link in my signature below. Look for the album titled "hot air engines". I am an old engine enthusiast and there are lots of pictures at this site of my hobby. Feel free to look around. Enjoy!

Regards
This email address is being protected from spambots. You need JavaScript enabled to view it.">This email address is being protected from spambots. You need JavaScript enabled to view it.
Nimbin, New South Wales
Australia 2480