Hot air and stirling engines

[Mark Smith 3Participant @marksmith3]

It can be tigged by a good welder. not much prep just pop the dsc on top or you could file it to a firm fit in the cylinder and have the tig man run  a bead around that.

Mark

[Ian S CParticipant @iansc]

I,v prepared two tubes for end caps,I,ll see about getting the welding done in the next day or two.Did one each way. Ian S C

[Ian S CParticipant @iansc]

Went and saw my tig man this afternoon, I don’t think he thought much of the idea of welding .4mm stainless, but after setting the welder on its lowest current.he only blew a couple df holes, but I don’t think he’d like too many more, he thought it proberbly better silver soldered.He recconed either way of fitting was ok, but the way I did the hot cylinder by making a cup shape was the ideal for extra thin metal. Just got to fit todays welding job, the Heylandt crown/hot cap, and the hot cylider. Also need to go to town and get some more cap screws for the cylider head, I’ll then be able to fire up and see if it s got any life. The Low temp engine goes just as well with ice under it, just that it rotates in the opposite direction. Ian S C

[Mark Smith 3Participant @marksmith3]

good progress, Ian. Mine still won’t  run so I have put it aside for a while to think about what could be the cause. I’m working on a conventional Beta as that design seems to work best for me.

Mark

[Ian S CParticipant @iansc]

What did you use for the hot cap? The thin tube I used is difficult to seal. I,v been running mine with an electric motor to run it in. The motor is only 18 watts, and when loaded gets quite warm,but as the engine frees up it runs longer before getting too hot.I also use the tacho to see the speed rise, it’ll proberbly need 3 or 4 hrs.Ian S C

[Mark Smith 3Participant @marksmith3]

I just used a mild steel tube from a shock absorber

[Gordon WParticipant @gordonw]

Hi all, back again. Finally got started on my engine, now the weather is only -4.
It’s based on old designs, seperate power cyl. and hot cyl.
My intention is to make just about everything variable so I can play about and try different settings etc., including pressurisation, well up to 2 or 3 bar.
I have a couple of questions that some more experienced people may help with, – Where is the optimum position along the displacer to take the hot air to power piston? Most designs show it about midway, before cooling section, some show it in the cooling section, my (bad) intuition says should be in the hottest part.  I’m making diffuser bush and gland in a replacable piece ,any sugestions for gland matl. and design? Also am reading Reader and Hooper on Stirling Engines, very useful.  :24:57

Edited By David Clark 1 on 18/02/2010 18:25:51

[Martin WParticipant @martinw]

ED

 

Whats up with this thread, and some others??? I am having trouble with the posts going under the ‘Ads’ on the right hand side!!! This does not happen on all pages of this thread so I don’t believe its my system. This page seems the worst so far, anybody else suffering from this on this thread???

 

Sorry to the contributors for straying off topic but it is annoying and needs sorting.

 

Cheers.

 

Martin W

[Mark Smith 3Participant @marksmith3]

I see what you mean, that hasn’t happened on this thread before but I  have seen it on others now and then.

Mark

[Les Jones 1Participant @lesjones1]

Hi,

         I am having the same problem with the adverts. I have tried Firefox 3.6, IE8

and Google chrome 4.0.249.89 (Latest version I think) 

A temporary way round it is to copy and past the text to notepad etc. To copy put the cursor on the first character. Hold the left mouse button down then drag the cursor  to the end of the text. The text will now be highlighted. Now press the control key and the C key together. This copies the text to the clipboard. now got to notepad and press control and V together. The text will appear in notepad.

Les.

[Martin WParticipant @martinw]

I don’t know whether somebody has done something but now the posts are OK and terminating before the ‘ads’ column.

 

ED done anything???

 

 

Martin W

[David Clark 13Participant @davidclark13]

Hi There

Yes, sorted it out.

regards David

 

[Mark Smith 3Participant @marksmith3]

Thanks David, all good.

[Mark Smith 3Participant @marksmith3]

Hi Gordon, I’m not sure about your intuition, but I think the idea is to keep the power piston as cool as possible so the transfer tube needs to be as far, as the design allows, from the hot end. If you place the tube at the hot end  then the air is heated twice: incoming and outgoing plus the extra dead space involved.

A young man of my aquaintance is going to university next year and entering the Engineering dept of Canterbury University (the one that developed the Whispergen stirling engine). He has asked me to help him build an engine for his entrance project, a task I am happy to oblige him with. I have CAD drawings of the Devon as seen in my album –  which was successful. I will get him to make as many of the parts as he can. I think this is great and he should get every bit of assistance and encouragement as I can give him. You never know what someone like him could achieve in the future. 

Mark

Edited By Mark Smith 3 on 19/02/2010 06:11:25

[Ian S CParticipant @iansc]

Hello Gordon, I agree with Mark The pressure transfer to the power cylinder should come of the cold end of the displacer cylinder. I have got a plan for aengine model that dates back to the 1930s that taps the pressure from midway down the displacer cylinder, I started building it when I first got into hot air engines, but stopped, and built a V type that ran for many years until pulled apart to make another engine. Mark give your friend my best wishes, and if any help required I’m here. Put some heat on the Ross Yoke engine tonight,but it needs freeing up quite a bit more. It should also get the cooling system hooked up. Ian S C

[Gordon WParticipant @gordonw]

Thanks for all that, will put in 2 tappings, one at cold end, one just before water jacket. Had not realised until recently how much research is being done, its a good thing.

[Ian S CParticipant @iansc]

Gordon, I found the old artical, its in an old magazene called “Mechanics” incorporating English Mechanics &The World of Science, The Amature mechanic & work, And it was a 1944 edition. The interesting thing about the engine is that the displacer is just under half the length of the displacer cylinder, so that when the displacer is at the cold end, the transfer tube is open to the hot air going to the power piston.When the displacer is at the hot end the transfer tube is open to the cold end. Both piston and displacer have a stroke of 1 1/4″,the displacer has a bore of 1″ and the power piston is 3/4″ dia, It has a 4 1/2″ dia flywheel,and the cold end has a water cooling tank. Ian S C

[Ian S CParticipant @iansc]

It’s a runner!! Got the Ross Yoke engine running today, its still a bit stiff so there is not much power yet, but I’v had it up to about 650rpm., it runs a bit rough but I think that when it gets up to 1000+ it should smooth out.Ian S C

[Mark Smith 3Participant @marksmith3]

That is good news, Ian. I wish I could say the same so I have parked it for a while to think about. Meantime getting on with other engine projects. I still can;t reply to your emails as it just gets tossed back address wrong, odd that

Mark

[Ian S CParticipant @iansc]

Mark, how heavy is your flywheel? I’m using the 6 1/2″ flywheel off the engine I had at Homebush, to start with a bigger one wouldn’t hurt, I think that once its run in a smaller one would do,but it does need the weight at first. I take it you got one the other day about a different type of engine. Back to my motor,I’v got to work out a pump system for the water cooling, the water jackets are too small and it won’t circulate on its own. I may have to put some fins on the bottom end of the stainless hot tube. Ian S C

[Ian S CParticipant @iansc]

I was doing some work on my Ross yoke enginge today, and looking at the side rod on the yoke and thinking, now there is a place to drive a pump,either a water pump for cooling, or a compressor for pressurising the engine. Ian S C

[Mark Smith 3Participant @marksmith3]

How is your engine coming along, Ian has it got more power now? Revs?  I have gone back to my pressurised engine and have started to install a bell crank in the bottom of the crankcase. Just have to decide what pins and bearings to use and work out the conrod lengths.

The young fellow I was telling you about has been talked out of his hot air project by his teacher who said it was too ambitious at this point, probably quite right as he  won’t make very much of it. His interest has, however, been ignited so to speak.

Mark

Edited By Mark Smith 3 on 16/03/2010 08:17:20

[Ian S CParticipant @iansc]

I’v got to give the motor a squirt of CRC every now and then, its still a bit tight. I,ll fit the radiator tomorrow, that’ll help a bit. I’v got two sources of pins, chassis of VHS machines etc, and other electronic/electrical stuff that goes round, and needle roller bearings. I would tend to go ahead and help the young lad build a simple engine, perhaps James G.Rizzo’s Dolly 1 or 2, or a little V type(only 1 crank needed), think his teacher is a bit of a pessermist. Even if he does’nt make it all he’ll have the motor and value it for many years. Ian S C

Edited By Ian S C on 16/03/2010 10:51:04

[Ian S CParticipant @iansc]

Hi , I’v found quite a good motor to use as a generator, it came from a Braun stick blender, it’s a 220v dc motor rated at 500w, the newer ones are 600w. This motor generates a good voltage even at low speeds, I was running it tonight at about 350rpm and 20volts. Ian S C

[Mark Smith 3Participant @marksmith3]

Which motor did you drive that with sounds impressive.

My ross yoke engine still refuses to run I am thinking now that the bore and stroke or capacity are too small for the size of the yoke whch is the same size as Andy Ross’s 35cc engine. Maybe not enough power to throw the thing over on the compression stroke. I am thinking of bringing it out to your place to see if you spot something I might have missed,

Just looking at the ross yoke engines in  Roy Darlington’s  book they are tiny compared to the engine capacity, mine is the other way round.

Mark

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