Member postings for WILLIAM FREEMAN 1

I have just acquired a kit to build a flame licker (vacuum) engine from the kit makers Bengs Modellbau.

I will provide updates on progress of the build. At first glance I must say this is a very comprehensive kit, and definitely worth the money.

I will definitely be considering getting a set of those drawings, I find it a much more attractive engine than the westbury. The way yours is turned out is immaculate, that goes a long way to making me want one!

Just studying your build more closely, I notice you used brass and stainless for the displacer and hot cap. The westbury drawings suggest using copper for both. I'm currently finding it difficult to purchase copper in the required sizes, and I'm now wondering whether making them from different materials would be a viable alternative.

I like the idea of a heat shielding skirt, definitely something to try on my next one.

I did very much like the style of the heinrici motor you have recently made, are there any commercial castings or drawings available to build one of that style? I am mainly talking about the arrangement of the piston and displacer all running in the same line, rather than separate like on the westbury.

I don't really have the ability in my workshop to machine one from solid. I have seen an old german website that appeared to have supplied them at one time, but seems it does no longer.

P.S thank you for rotating the image!

I've now completed the engine and the album of the engine is complete containing a good pictoral log of the build. I've attached a picture of the engine below, which the forum has rotated for an unknown reason. I've also attached a video of it running indoors, it runs very nicely now and is much quieter since I remade the gudgeon pin on the power piston. Hopefully this can be seen in the video below. I'm intending on building a meths burner for use under the engine as the bunsen burner isn't really suitable. The heat from the burner seems to go far too high in the furnace, losing the ability to have a 'hot' end and a 'cold' end. The bunsen burner seemed to create a 'hot' end and a 'warm' end. A small meths flame underneath would make the engine much more efficient I'm sure.

Edited By JasonB on 02/03/2021 11:23:37

Another quick video update, I'm now happy with how the engine is running and I've stripped it down for a final clean and reassembly before the full strip down for painting. I've also made a small water tank which can be fitted for extended running. I've also uploaded another video to youtube of the engine on the kitchen worktop, showing its free running. which hopefully should appear below.

I've decided after having a great deal of fun with this engine that I'm going to build another one.

Finally some good news on the engine front. after making a bush it seals far better and now runs far better too. The engine has a slight knock from the piston gudgeon pin. But other than that she's in fine fettle now. Feeling a lot more confident in terms of hot air engines, having never made one before. There does seem to be a lack of widely available knowledge for hot air engines. Information on this forum has been very helpful.

After a bit of playing she is now running well. moving onto sorting the gudgeon pin knock and making the furnace next.

https://youtu.be/LNw_g1b9hyw

I had a bit of a play last night with seemingly better results. In the join between the water jacket and liner, I had made a brass bush to fit the displacer rod and hopefully alleviate my pressure loss issues. there was still some slight leakage but the engine ran much better. I'm still convinced that the engine is 'breathing' and losing power. I assembled it freshly with the bush in place and the engine was difficult to turnover due to the vacuum and pressure the power cylinder was creating. Is that normal?

I'll have another session of playing tonight, but I think there is light at the end of the tunnel.

Will

Hi Jason,

I watched your video of your scratch build with awe. Especially how long it runs with no flame at all. The drawings for the westbury contains 3 o ring grooves. One of which is on the displacer rod. this is what I'm assuming is causing me the problems. Out of interest does your engine have a drain plug to let the air / pressure out?

When i draw a vacuum with my mouth on mine it draws a good vacuum but after a few seconds it has disappeared, telling me i have a leak somewhere. It had its first run on Sunday night, and I can see it being a nightly task at the moment for me to strip it down and try a new configuration until it works as well as yours.

Regards

Will

A bit of forum help may be required for my next stages, the engine is complete (apart from a furnace). I'll jot down a few bullet points and hopefully someone on here will be able to give me some ideas.

The engine turns over nicely, and will do around 6 revolutions when spun by hand.

Sealing of the components seems to be my main issue.

I have had the engine running, but it seemed to need an awful lot of heat to run, I'm assuming this was as the heat was substituting for the loss in pressure.

I'm definitely picking up that the drawings / build notes seem to omit some major parts about sealing the engine up.

The power cylinder is sealed well, so I can eliminate that from my enquiries.

the issues I'm having are definitely around sealing the displacer rod, where the jacket meets the liner, and where the displacer meets the liner. Can't quite say i'm tearing my hair out just yet. But I can see why not many of these engines never get finished.

I'm trying to use a combination of O rings, PTFE tape, and non setting gasket sealant.

And as you can imagine with this engine low friction is key, so i feel i'm stuck between a rock and a hard place.

Any advice would be welcomed.

Hi James, I have a couple of Brian Caton's Live Steam loco's in 009 (same scale as 00 but for narrow gauge) and I have good knowledge of how his 00 locos worked. I was lucky enough to be a good friend of Brian, and he was my mentor in model engineering for many years. he was a superb model engineer with an encyclopedic knowledge of the railways.

The 00 locos had a refillable gas tank located in the tender and a gas fired centre flue boiler mounted in the traditional place. The locos were driven by a single acting piston valve engine with slip eccentric mounted in the cab. The crank of the engine was running parallel to the loco and then gear reduced down and linked to one of the driving axles of the loco. From there the coupling rods of the model did their own work. The engines were not self starting but after a gentle push in either direction the engine would run happily, in forward or reverse, due to the slip eccentric. the locos were fitted with a regulator which was servo controlled through the track, this could be isolated in order to not play havoc with 'foreign' layouts. The regulator could also be controlled from the cab by hand, if you were delicate.

I'd be very happy to answer any questions you have on his loco's I can probably find a few pictures of them.

Regards,

Will

Another reasonably slow week for machining parts. It was the water jackets turn to be turned. An awkward lump to hold, given by its pure size. It seems like a trick was missed by Reeves / Westbury in the design here as this casting just stretches over the very common centre height of 3.5” meaning it cannot be held in my myford. Due to this I had to borrow my dads EMCO Compact 8, a much daintier lathe, but with a greater centre height of 4 inches. The clearance on this casting between itself and the bed was roughly about 0.5mm! this brought many issues with it, including being very watchful of the carriage placement and also having to have a monstrously long boring bar. The total length of the boring bar came in at 8 inches! To take into account the 3inches of depth and the 3 inches of air between the carriage and the casting. A real pig! The casting itself was overly large I thought, meaning nearly 3/8” needed to be taken off the bottom face and a 1/4” off the top. Given how well aligned the casting was, all this meant was copious amounts of winding in and out on the topslide.

I’ve included some pictures and brief build comments below.

Initial boring of the casting,

clearance between casting and lathe bed. Very tight!

finished facing bottom and boring recess for liner

test fitted liner to jacket.

top face cleaned up

4BA C/Sunk drilled through from jacket into the liner

Edited By JasonB on 26/01/2021 12:59:43

The past week, has been a slow one in terms of engineering, with work demands being higher than normal. I still managed to get some bits completed, but not as many as i would've liked.

Annoyingly the water jacket casting will not fit in the myford, due to the 3.5" swing. I may choose to modify this slightly to make it fit. It seems a slight oversight that it wont fit, given that the majority of home engineers lathes are 3.5" swing. But we shall not be beaten!

A few pictures of progress in the last week are included below.

Flywheel truing on a tapered mandrel

Machining the crank side flywheel

Water Jacket Liner

Picture of the finished liner below

Yesterday evening brought about some more machining time. I had already decided against trying to cut a 2" x 24 TPI thread on the hot end cap and liner. So as the drawing suggests I went down the grub screw route. I had stacks of 4BA grub screws so instead of the 4 on the drawing I decided to put 6 in. to aid with this, I clamped up the hot end cap in the rotary table and spotted with a pin pointed centre drill the 6 holes for tapping 4BA.

I don't know if anyone else has any tips for drilling bronze / gunmetal, but i find it the most awful thing to drill. It is of no value to pilot drill as this will just cause the drill to snatch in an attempt by the drill press to remove your arm.

After very careful drilling at 3mm to 4BA tapping size I moved on to machining the flywheels.

The flywheels are slightly different as can be seen in the pictures, one has a cast boss for the crank pin and the other does not.

I started on the non-crank pin flywheel. this turned out to be an odd setup in the lathe, as the boss on the flywheel was not centred well enough, nor did it have enough protruding for me to get a good grip on it in the chuck.

Whilst playing around with the flywheel I realised that the inside of the flywheel tread was actually in good shape, and appeared to run nearly true. After a bit of fettling I decided this was the best way forward for work holding.

So I set the lathe in back gear running at around 40rpm and set to work. the quality of the iron was very good apart from the expected scale on the outer elements. Once the scale was removed and the flywheel was round, I picked up the rpm to 200 and went for finishing cuts.

I have centre drilled and machined the boss ready to be drilled and reamed 3/8".

All being well I should be able to get that and the other side machined tonight. If all goes very well I should be able to make a start on the crank side flywheel.

This weekend had brought about some rapid progress on the Westbury Heinrici. It seems the duo of no housework and a national lockdown is good for model engineering.

I've created an album for the build of this engine, which is HERE

If anyone would like to know more about this don't hesitate to ask.

A few notes as i've been building I've included here. As with the posts above, I'd be glad to hear from someone else who has built one of these for any tips and tricks.

Piston yoke boss machined.

Piston yoke turned around in chuck for machining

Piston yoke with all turning complete

piston yoke having slot milled for conrod

completed piston and gudgeon pin assembly

completed piston and conrod

completed piston and conrod, please excuse the snacks...

displacer rod in the lathe, thread slightly recessed to provide a perfect parallel alignment between it and the cap

displacer cap machined and test fitted to displacer itself. whilst also being screwed into displacer rod and in turn conrod.

machining hot end cap outer

machining hot end cap, innerfinished hot end cap, test fitted to hot end.

I started to make the piston last night and after a few hours of what seemed like endless swarf making, I had finished, it seems to fit in the bore snugly at the moment, but I think after some running in in oil it should be perfect for this engine. Tonight I will start on the piston yoke. the finish is as good as i can make it at the moment, it was done using a round nosed tipped tool, traversed by hand rather than by using the carriage feed. Myford running at about 900rpm, it took me a few minutes to traverse the 1 1/2" but the finish came up quite well. Again, when run in with oil i'm sure they will bed together nicely.

Afternoon all,

As promised, I started on my set of castings just after Christmas, as my Stuart Beam took a little bit longer than planned. I'm afraid the pictures are in reverse order.

So far the parts for this engine seem relatively straightforward, the conrod was made on a Saturday, meaning I had a good 10 hours of making. The biggest piece of grief that came with the conrod was a broken drill almost immediately after centre drilling for the big end bolts. A 2mm drill from a brand new 'draper' set I had received for Christmas, this meant that instead of drilling straight through the big end, I had to split the big end first and then meet the broken drill from the other side before attacking it for a good period of time with a punch. Luckily I managed to get all the pieces out and from there on in it was plain sailing. On a side note the drill set has gone back to the seller after I took out the 2.5mm drill, put it in the lathe and measured the run out at the tip. This measure 2.5mm, gobsmacked that anyone can be producing such tat in this day and age.

The cylinder was a much smoother affair. The only grief coming from trying to get a top finish over the 3 inch stroke of the bore. This took many many passes and a lot of patience, but hopefully you'll be able to see from the picture, I got there in the end.

I've now started work on the piston and piston yoke. my first impressions of the piston design is that it will make an awful lot of cast iron waste.

Will

Agreed Howard,

I have a trusty Super 7 which has never let me down yet. That takes care of most of my larger models. For smaller parts I have a Pultra 1770 which is excellent for precise work.

Having been brought up with lathe I think not having one would feel like losing a limb!

Will

Engines built from the Reeves castings do seem very few and far between. I've previously only made steam engines. From reading various forum posts it would seem there is definitely a different knack required for building Stirling engines. In terms of the absolute free running nature of them, lack of tight spots etc...

I'll have lots of questions no doubt!

Hi Howard,

I've always been an old head on young shoulders, I've cracked the picture uploading I think, so a few of the 8 should appear below.

I've had 3 really excellent teachers in model engineering disciplines, and without them I wouldn't be able to use a saw or file, let alone a lathe!