A useful Stirling engine.

[Engine BuilderParticipant @enginebuilder]

Dick

I can't see how a nice diaphragm can be made with a bead roller. OK if it were 3 foot diameter but for an engine like this it has to be a precision job. We will have to wait until Cyril shows us how.

[Ian S CParticipant @iansc]

With the planar spring I suspect I know where the noise is coming from, but I'll need to make a few more of them to find out. Think mine may be of a different pattern. How thick was the saw blade, I suspect it was not one of the new ones witrh a hard blade. Ian S C

[lyricParticipant @lyric]

Hi Ian,

The spring was made from a new saw with hard teeth it is .028" thick

I have just made another one and have taken photos of the various set ups which will go on Youtube

in the near future. Cyril

[David Paterson 4Participant @davidpaterson4]

G'day all,

I have now got stuck into the videos and the references (except the old ME that I don't have acopy of (sorry Lyyric).

I was wondering why you wouldn't use a crank on the TMG to get DC power? I'm really not sure about any of this electrical stuff.

If I can sot out the current information, it seems that I need to be thinking in terms of either a TMG and doing somethig to sort the power, or a stirling of arond 30cc, probably pressurised, and using gass to get enough heat. (given other constraints about camping etc). The generator needs to be bigger than a video capstan drive If that is in the right ballpark.

Not sure my skills are up to the burner, but as a start point, can anyone point me at some plans please? happy for commercial source if there is some assurance of a 'workable'.

regards

[Ian S CParticipant @iansc]

Don't worry about the AC current, that can be easily catered for with a diode, preferably either 4 separate ones, or a Bridge rectifier, often a black plastic block about an inch square by 3/8" thick, with 4 legs/ connections out the bottom (there are a number of other shapes).

The TMG would not have a long enough stroke to drive a crank, and rotary motion would defeat the idea of the TMG.

As for burners, for my engines that require a burner under them, I use the burners from old camp stoves. For engines with the heating at the top, it gets a little more difficult, I make a ring burner, and fit the Bunsen burner part from a camp stove. My idea of using a burner at the top of a motor is that heat rises, so it will take longer to get to the cold end, which is at the bottom. Ian S C

[Richard ParsonsParticipant @richardparsons61721]

Last night I was sitting enjoying about ½ litres of something golden, cool and very refreshing. I was running a ‘to do’ list through my head when suddenly I realised that I was a ‘damned old fool’. The diaphragm has to have be slightly convex on the displacer side, they also need one or more annular grooves in them to allow for them to flex.

I realised that the way to make the diaphragm for the TMG (Harwell engine) was to ‘spin it’. Ok I have only used the technique metal spinning once or twice before, but each time it worked.

How You ask?

Ok I would fix a nice lump of hard-ish wood to the face plate and turn a shallow concavity in to it about 1-2 mm deep with however many annular grooves I needed. This would be the ‘pattern/mould’. I would then make a ‘presser’ block for the tailstock which was convex . it would have to be smaller than the smallest annular grooves I would take a square bit of annealed sheer big enough to get the diaphragm out of with holes drilled in the corners and its centre marked. Centre up the sheet over the pattern and using the holes screw it to the back board. With the whole thing spinning, I would then slowly push in the ‘presser’ block nice and tight. I would make a tool from a bit of bar which had a polished ball end. With the lathe still spinning I would form the grooves by pushing it into the annular groves in the pattern. The correct lubricant to use is Russian Tallow but with such shallow spinning I think you could get away with a bit of pork fat.

When you have finished you could trepan it to size,

I know that my method is the other way round to that described in Wikipedia but we are only doing a very shallow forming. Our requirements are far less rigorous and our ‘draw is far smaller than the one shown here.

Good luck and regards

Dick

I just was not thinking properly

[TerrydParticipant @terryd72465]

Posted by David Paterson 4 on 02/04/2012 02:53:12:

G'day all,

Last weekend I was at an event in canberra called The Mont. This is a 24hour endurance mountainbike race, and half of it is done with very expensive LED on head and handlebars. recharging is gerally done a a central point because these events are well out in the sticks.

I have built a partially satisfactory low temp differential stirling.

The idea is to build a small stirling capable of running a generator sufficient to recharge mountainbike lights. How do I start?……………………..

Dave

Hi Dave,

I think that I would use a bike dynamo for charging batteries (with a bit of ingenuity) and use the Stirling for display. To paraphrase Maudslay, for good design you need to 'Get rid of all that is not needed'.

T

[lyricParticipant @lyric]

Hi Richard,

Why didn't I think of that ? I look forward to seeing the end result.

Cyril ( Barumman)

[Richard ParsonsParticipant @richardparsons61721]

Lyric Yes but I have got hold of two stainless mugs which when I have gotten the handles off seem fit into each other. But this is due to the ‘draft’ on them. I will have to spin the inner one down a might so it will not jam as it bottoms or tops out depending the way you look at it. My real worry is going to be if the stainless can be silver soldered. I do not know this yet.

I am still looking for ‘catering tins’ to make the diaphragm out of. The problem here will be can I actually eat the contents of the tin before it goes bad or I sicken of it.

Luckily I am beyond the reach of the Goblins and Gnomes of Elfinsafety. In the UK these folk will not allow hand held tools (any more). They made threatening noises about the use of the graver tool rest on a 6mm Lorch

At the moment I am just collecting the materials. Summer time is when I do that ,as most of my days are spent sorting out the broken mowers and strimmers etc. Hungarians are in the main ‘one man’ demolition experts. They can, and do, break anything (and everything). It is deeply ingrained in their psyche. If you can break the tool you do not have to do the work and they will spend an hour trying to bust their tools instead of doing a 10 minute job of work using them.

Finally there is another way. It was invented by (I think) ‘Tubal Cain’. It consisted of an aluminium pressure cooking pot (a bit beefed up). This became the boiler. Packed inside it was a S.T. ‘Sirius’ or a ‘Sun’ and a motorbike dynamo plus pipes etc. These were dropped to the French Resistance (the Maquis) and others to let them recharge their radio batteries whilst in the ‘bush’.

Rdgs

Dick

[Ian S CParticipant @iansc]

Yes there where one or two different boilers for Sirius, and the battery charger, one was an army pressure cooker as you say, a bit bigger than a modern domestic one I imagine. I think the generator was a bit of army gear, may have been a hand driven one origionaly. Ian S C

[Joseph RamonParticipant @josephramon28170]

"Last weekend I was at an event in canberra called The Mont. This is a 24hour endurance mountainbike race,"

I look forward to seeing someone compete on a Stirling Cycle.

The Sirus-based generator package was designed by Ian Bradley of 'Duplex' fame.

Dick – I deal with a lot of H&S in my job, in an industry that sometimes, but thankfully very rarely, kills people. There is an industry itself in propagating the elfinsafety myths, but most of them are myths. The HSE is much more proprtionate in its approach than people think – we had a RIDDOR a couple of months ago. It was clear (afterwards) that we need to take some remedial action to prevnt a repeat. All we got from HSE was an acknowledgement of our report. If it happened again, we would be in trouble, but we can document that we have acted to eliminate the hazard and in all honesty none of the cations required were very expensive or time consuming. What was costly was paying for a staff member to sit watching digital TV for eight weeks.

Joey

[TerrydParticipant @terryd72465]

Hi Joey,

I very much agree with you over the overreaction to the HSE that some contributors have on this (and other) forums. Most of the criticisms are caused by misunderstandings and urban myth (such as banning conkers). Most of the critics also don't seem to, or don't want to, understand that the HSE only covers health and safety at work and not in the domestic / hobby environment. Dick seems to spend so much of his time criticising the people of Hungary, whether incompetent, stubborn workers or uncooperative suppliers that I sometimes wonder why he stays there. Surely not simply because he is afraid of the HSE here that he so loves to demean?

Confusedly

Terry

[Richard ParsonsParticipant @richardparsons61721]

Terry    I am only here for the beer, baccy (I can buy a very good Cavendish at a price I can afford), wine and for the fact that as they cannot talk to me they generally leave me alone.  If they annoy me I tend to speak in the dialect of either of my early child hood  (Cockney) or my later childhood Cotswold with its "Oh Arr, Arr, buggerit, bist jonnuk? 'this yer hookem',  and universal 'Didder?' "

The Hungarians en-mass have other concerns on their mind, like a 93 year old treaty. Their unwillingness to work efficiently dates back to the Communist period when 'They pretend to pay us so we pretend to work!' and old habits die hard. Their general attitudes are in part caused by their language which is very complex and you can only really learn as a child (it is not an Indo European language) Because of this they are very 'insular' and belive that they are very superior to their minorities (the Roma) and to the rest of the world.  They will never accept blame for their failures.  Their fellow Hungarian speakers who live as minorities in other lands (Romania, Slovakia Serbia etc.) are very different as they have been exposed to and live with strangers on a very large scale. But as one French Generals said "Les Hongoise sont enfants charment". (The Hungarians are charming children). The suppliers are uncooperative because again of their (communist) past . Very few have learned that their customers are important, but most do not . Nor do they understand the ideas of honest dealings and competition. Most of them will only do as much as their local competitors, very few will go the extra inch .  If they can cheat you they are cleverer than you.

In the UK the Goblins of HSE claim that 'hobbies' are 'within their bailiwick' and 'you will have to prove your hobby aint'.

Rdgs

Dick

Edited By Richard Parsons on 20/04/2012 14:47:53

[lyricParticipant @lyric]

With all due respect what's this got to do with Stirling Engines. ???

[Richard ParsonsParticipant @richardparsons61721]

Lyric I agree with you but the question was put

Rdgs

Dick

[TerrydParticipant @terryd72465]

Posted by Richard Parsons on 20/04/2012 14:33:42:
………….

In the UK the Goblins of HSE claim that 'hobbies' are 'within their bailiwick' and 'you will have to prove your hobby aint'.

Rdgs

Dick

Edited By Richard Parsons on 20/04/2012 14:47:53

Sorry Dick,

that's just a load of bunkum and urban mythology. Note the full title, Health and Safety at Work.

Quote from Official Website:

"HSE’s responsibilities

HSE is responsible for enforcing health and safety at workplaces including:

• factories
• farms
• building sites
• nuclear installations
• mines
• schools and colleges
• fairgrounds
• gas, electricity and water systems
• hospitals and nursing homes
• central and local government premises
• offshore installations"

My garage ain't any one of those and over 25 years have yet to be raided by the mob in white coats, but I know that won't satisfy the conspiracy theorists among us but that's the way it is. BTW I didn't emigrate, I gave up smoking instead.

Regards

T

Edited By Terryd on 21/04/2012 09:36:56

[Ady1Participant @ady1]

I think that I would use a bike dynamo for charging batteries (with a bit of ingenuity) and use the Stirling for display. To paraphrase Maudslay, for good design you need to 'Get rid of all that is not needed'

Those bayliss wind up torches use a 3 phase winder and appear to be extremely fast and efficient at recharging NiMH batteries.

I'm actually a bit surprised that none of those electric kiddie scooters are using this technology yet, the torch technology probbly costs about a fiver tops to source

[Ian S CParticipant @iansc]

Ady1, one would really want a bit more than a bike dynamo to charge a number of batteries, and the idea is to find a simple motor to take over the winding, so he can go get a can of XXXX (Ausies can't spell, so they just use XXXX for Beer),or some other brand. I'v got a little Villiers 2 stroke with a Lucas  car alternator on it, it will run with a 400 Watt load continuous, or a bit over 500 Watts for 20 miniutes, if the wind is not blowing the right direction it starts to sieze up at this load (you could fit a fan). You don't need too much throttle, so its not too noisy. It works well as a battery charger. A 4 stroke motor, horizontal shaft best, would be even better, specially if you get it for the same price as mine, I had to buy petrol, and oil, You'v just got to be there when someone is chucking out their old mower. I think someone said that the Victor motor used on the early Victor mowers(Aussy made) could be used horizontal. Ian S C

Edited By Ian S C on 21/04/2012 11:33:16

[TerrydParticipant @terryd72465]

Hi Ian,

I would have thought that 400W is a bit over the top for charging a couple of say 2000mA Metal Hydride cells, surely a smaller source would be more than adequate?

Regards

T

[Donhe7Participant @donhe7]

Posted by Ian S C on 21/04/2012 11:32:22:

so he can go get a can of XXXX (Ausies can't spell, so they just use XXXX for Beer),or some other brand.

Edited By Ian S C on 21/04/2012 11:33:16

That's Queenslanders who can't spell beer, we South Aussies used to drink Southwark or West End, but since the South African take-over, it's Coopers beer for us, as it's Australian owned!!!

With regard to the Villiers two-stroke, I once tried a small Suffolk "twoey" on a car generator, and promptly "blew" a 100 watt 12volt sealed beam unit , so the Villiers should be "cruisin' "

donhe7

[Ian S CParticipant @iansc]

donhe7, the Lucas alternator has a built in regulator, so no problem there, given a bit more power, the load could be increased, I think my alternator is a 45 amp one, it's best to get one with an internal regulator, you do of cause need a 12v supply to strike the charge, but two little 9 v batteries will do the trick, they are only needed for a few seconds until the alternator takes over. I'v got an imersion heater, so I can boil a cup of water for a cupper (takes about a 1/4 of an hr). I believe the origional idea was to have a charger so that all racers could charge their batteries.

You can use a car generator instead, with a regulator, does not need a voltage supply to start charging, its not so efficient, an harder to find these days, but quite a good way to go. Ian S C

[Donhe7Participant @donhe7]

Posted by Ian S C on 22/04/2012 07:42:35:

 

You can use a car generator instead, with a regulator, does not need a voltage supply to start charging, its not so efficient, an harder to find these days, but quite a good way to go. Ian S C

Agreed, Ian, a generator is not as efficient, and lacks the built in regulator, but at the time I was toying with the idea for camping, and alternators were not so plentiful and cheap as is the case today.

We did try an alternator temporarily on a Briggs and Stratton fourstroke, without any excitation, and found that it would, infact, self-excite, but the B&S then started to labour, even without a load, and as it was only a test the project was discontinued.

All this is a far cry from the original purpose of charging 2000mAH NiMh cells, so we'll let it go at that!!!

How hard would it be to locate a bicycle hub generator and arrange a suitable drive system??

donhe7

Edited By Donhe7 on 22/04/2012 09:00:53

Edited By Donhe7 on 22/04/2012 09:01:38

[Ian S CParticipant @iansc]

As bike dynos go, a Sturmy Archer hub dyno would give you the most power output, you need to find an old junked bike, think they were about 9V, were as the ones that run on the tire are 6V, the hub dyno gives a good voltage at a fairly low speed, they all need a rectifier, but thats not much of a problem. Ian S C

[Donhe7Participant @donhe7]

Posted by Ian S C on 22/04/2012 13:27:07:

As bike dynos go, a Sturmy Archer hub dyno would give you the most power output, you need to find an old junked bike, think they were about 9V, were as the ones that run on the tire are 6V, the hub dyno gives a good voltage at a fairly low speed, they all need a rectifier, but thats not much of a problem. Ian S C

Further thoughts on the Sturmey Acher Dyno-hub, they must be driven at a slow speed, as they drop off in efficiency at too high a speed, as an old friend found out a number of years ago, when he tried to drive one with a model engine, it seems that the stator saturates above a certain speed and reduces the output. However, if a small steam engine or an efficient Stirling engine could be coupled to it, it could answer the OPs prayer.

donhe7

[David Paterson 4Participant @davidpaterson4]

Guys,

Struggling to keep up- full time employed, Army Reserve, 3 teenage kids and Model Eng means that these projects take a long time to germinate.

Having said that – think I can start to put ideas into a sketchbook at least. Power output for my lights needs to be at 12vDC 1 amp. I still like the stirling idea, and have seen both pohmbic and Ross yoke ideas that seem scalable.

Heat at the top makes sense to me – can always use the waste heat to run the billy. Not sure how to get a ring of fire yet, so diggin into lod mags an online. I'm a bit partial to 'primus', but suspect that I will have to go a long way before the current archives to find an example I can cull for a plan. The Harris boiler book shows a jet, but not how you might convert this to a ring.

Local mates tell me that the Sturmy Archer is now a collectable, rather than a source, but the the local electronics place JayCar may well have something suitable in thier electronics section.

So, more digging yet, and enjoying the rest of the discussion.

regards

Dave

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