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machines which I have made, am making, or intend to make, and some other stuff. If you find this site interesting, please leave a comment.

Tag: Stirling engine

Model Engines on Steam

It is Geelong Show time again.  It is actually titled the Royal Geelong Show, but having had more than a gutful of royal non-entities visitors being adored by unthinking cringers, flocking around Harry and Meaghan Kardashian, Windsor, and being a committed republican, I refuse to bother with the “Royal” handle.  (they are probably very nice people, I just cannot stomach the hoo-ha).

More importantly, it gives us steam junkies a chance to run our small engines on real hot steam.

For a treat, I am sharing four short clips taken today.

The first is a small beam engine, made by Swen Pettig.

The next two engines you have probably seen before.  My beam engine, and the triple expansion engine.

The small engine to the right is a Stirling engine which is running on the heat from the exhausted steam from the beam engine.

The triple is leaking a bit more than it should, although it is running amazingly smoothly on 25-30 psi.  The valve glands need repacking.

And finally, a model IC engine, the really odd Atkinson.  A 100+ year old design.  2 stroke. Made by Rudi vanderElst

 

Der Tiger at Geelong Model Engineers

GSMEE (Geelong Society of Model and Experimental Engineers) had its annual exhibition at Osborne House, North Geelong last weekend.

Osborne House used to be Australia’s submarine headquarters, and it still houses a superb maritime museum.  It is also home to the Vietnam Veteran’s Association.  And other clubs such as GSMEE and The Camera Club.

We could not have asked for better weather.  Two glorious spring days.  With Corio Bay sparkling in the background.

And guarding the entrance of our exhibition was a WW2 German Tiger Tank.

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At 1/5 scale, weighing 1/4 tonne, powered by a 12 cylinder gasoline engine.

I have featured this machine before (see Bendigo exhibition).  It is still fascinating and awesome.

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Gerard Dean operating the controls, which are a close copy of the original, even down to the warning in German that “the enemy is listening”.

Gerard explained that the original was prone to engine overheating, gearbox grenading, transmission failure and track jamming.  His demonstration on Sunday was terminated by sudden graunching in the gearbox.  An authentic demonstration indeed.

Normally Gerard drives the tank up ramps onto his ute.   On this occasion we pushed it up.

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Do you imagine that he would get the odd double take as he drives home on the freeway?

Another outstanding exhibitor was John Ramm, with his scale Merlin engine, Volkswagen engine, and 7 cylinder radial aero engine.

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John Ramm’s Spitfire Merlin engine.  1/4 scale, 75cc.  Unfortunately I missed seeing it running.

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John Ramm’s 7 cylinder radial aero engine.

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John Ramms scale VW engine.  Said to be 75cc, but with VW who knows?

There were many other wonderful engines, model ships, planes, and workshop tools.  And an excellent trade display (thanks Ausee Tools).

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Peter Bodman’s self made 3D printer was busy making parts all weekend.  Many of the components of this printer were made on his previous Mark 1 printer.

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Willi Van Leeuwen had a lovely display of model ships and boats including this steam powered boat.

Last, and least, the Norm Hatherly Stirling Engine prize was won by yours Truly.

Model Marine Boiler and another Koffiekop.

At the recent Geelong Society of Experimental and Model Engineers (GSMEE) meeting, several interesting models were presented, including my Koffiekop engine.   And another Koffiekop, this one by Stuart T.

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Stuart T is an expert engineer and machinist. He CNC’d most of the components in his engine, and has enough spare parts to make another 6 of them. He says each part takes a couple of hours to draw and program, then 5 minutes of machining to spit out half a dozen.

Another most interesting model is the marine boiler by Rudy pictured below.  Rudy was a marine engineer, and some of his ships were steam powered.  This model is made from his memory of one of those.  The odd external shape is to conform with the ship’s hull, starboard (right hand) side.

Model ship's boiler. it is approx 300-400mm high. The fire box is stainless steel. The copper boiler and water tank and superheater were TIG welded. The water tubes are silver soldered.

Model ship’s boiler. it is approx 300-400mm high. The fire box is stainless steel. The copper boiler and water tank and superheater were TIG welded. The water tubes are silver soldered.

The water tubes, super heater and boiler.

The water tank, water tubes, super heater and boiler.

The water gauge was scratch built by Rudy. The pressure gauge was bought.

The water gauge was scratch built by Rudy. The pressure gauge was bought.

Not sure what these attachment points are called, but they look interesting coming off the hemispherical ends of the boiler.

Not sure what these attachment points are called, but they look interesting coming off the almost hemispherical ends of the boiler.

Rudy made the nameplate on an engraving machine, then formed the domed shape.

Rudy made the nameplate on an engraving machine, then formed the domed shape.

Rudy has pressure tested the boiler to 100psi.  He reckons that it would be good for 200psi.  He tested it with compressed air, submerged in a barrel of water.  That would show any leaks.  And if it did happen to blow, the force would be diffused by the water.

Stirling Engine Failure. Now Successful!!

The Ridders “Bobber” Stirling engine which I made in 2014, and which defied all attempts to make it work, is now functioning beautifully!

After I completed the Koffiekop engine, and saw it working, I realised that I had not been adequately  particular with some of the machining aspects of the Bobber.

So I took the Bobber off the shelf, took it apart, and remachined the bore, made a new piston, and a new connecting rod bush.  Then I polished the bore using Gumption (see old post about Gumption) on a wooden dowel which was turned precisely to the correct diameter.  I was not concerned about some splits in the wood, as they acted as reservoirs for the Gumption.  After cleaning out the Gumption residue the bore was ultra smooth and shiny.   The piston slid easily on its own (miniscule) weight, and the sliding ceased when the top end was blocked with a finger tip.

I experimented with fuels (olive oil too much carbon deposition, but methylated spirits fine), number of ceramic ball bearings (three specified in the plans, but two seemed to work better), and most importantly, and serendipitously (that one’s for you John), reversed the direction of the flywheel.

See the video below for the result.

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Photo of the operating Bobber engine.  The white balls are ceramic bearings.  The piston is now made of graphite rather than the original steel, and I was particularly particular about the polish of the cylinder bore and the fit of the piston.

Video of the operating Bobber engine.

Flywheel and Sugru

Firstly the SUGRU update.

Sugru, if you have been following this blog, is the flexible black insulating repair compound which I used to repair some electric cables on my lathe.   The cables supply power to the stepper motors, so they are in constant flexing motion when the lathe is operating.  I wondered whether the Sugru would remain adherent and intact.

Well, I am pleased to report that after several weeks use, the Sugru looks as good as the day I applied it.  A winner!

The flywheel.

This is the flywheel after some sanding and polishing with a Dremel.

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The 100mm flywheel, with lubricant ready to be applied.

I might have to make another Stirling engine to use it.

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