Stirlingengineforum.com

I have tried over and over and over, I'm just about at the point where I think it all might be a hoax. I'm not sure these things will actually work at all. Let me tell you this, I have built 7 seperate engines and not one of them will sustain even the slightest notion of self movement. I thought maybe it was the cam length or maybe the baloon wasn't compressing air or idk.. I'm so flustered I'm almost ready to buy one. I know these facts.. Tell me what isn't right. Displacer needs to fit tight but still fall on its own, can needs to be mostly sealed, baloon needs to be airtight and fit sort of loose. Displacer cam slot needs to travel Same distance and the displacer is able to move. Now does the baloon cam slot have a perticular ratio compared to the displacer cam slot? Also I know the cam slots need to be at 90' angles. I have all types of flywheels I've tried and I've tried steel wool and plant foam and cardboard as displacers. I have 3 of each type, side baloon engine and standard baloon in the middle types. I built one under my own design the works even less!!! How can you actually built of of these impossible engines?? Anyone willing to sell one if they exist?

Might pay if you can put up some photos, just to give some better idea of what you have. But one thing the displacer should have a clearance of say 1 mm to 1.5 mm, it should not touch the cylinder wall, or either end. By "CAM" i think you mean crankshaft, if it is a BETA, ie., coaxial type motor, if for example the power stroke (balloon) is 1/2", the displacer would be 3/4". What sort of heating are you using? Ian S C

Simple analysis would conclude after 7 attemps that you have made 7 different mistakes each time, or the same mistake 7 times. The most likely conclusion is that your repeating an error. Do you have a working understanding of how a simple stirling engine works? First you stated you got no movement at all. Since you didnt give us much to go on I take that literally. The weight of the displacer has pull the displacer to the botton of the cylinder,then you added heat to the bottom of the cylinder. You should have noticed the balloon( the power piston) expanded. Heated gas expands . If this didnt happen there is your problem. You have a leak somewhere on the cans surface. What model did you copy? Give the website.

I think it might be an idea to look at www.boydhouse.com/stirling/ Darryl boyd's engines are what you are looking for. Ian S C

It's hard to help without any pictures of information :) But it's probably leaking too much air somewhere.

Thank you guys for all of your replys. Sorry if I sounded frustrated! The main type I have been building is the two aluminum cans type. First, I made a steel wool displacer that fit tightly in the can, then I twisted round and round until it was compact and fell under its own weight. Second, I stretched a balloon over the open end of the displacer's(bottom) can. I then fitted the ballon with a bottle cap and a hole just big enuf for the wire to drop thru to the displacer. After that, I mounted the upper can with crankshaft intact. For the crank shaft I have the displacer lifter(fishing string wire) position at the very top position and then I pulled the displacer top the top with my hand by pulling the string and attached it to the crankshaft uppermost position. I did this so that when the crank turns to the most upper position the displacer is also in the most upper position.(is this right?) The crank arm depths, I decided on by 1/2 of the distance of the displacer movement. In other words if the displacer moved 3in I made the crank arm for the displacer 1.5in so that a full turn would lift the displacer the full 3in.(that seems right) then I pushed stiff wire thru the bottle cap for the push rods and attached them on the opposite crank arm at its most upper position.(balloon stretched out but with no tension). Then I attach the fly wheel made of CDs and and mayo lid. It all turns and looks right. It looks like a working model but there's no action after the flywheel is spun. My crankshaft arms are 90' apart(do the lengths of them have a perticular ratio)? Also, one more question sorry!! Does the balloon need to travel the same distance as the displacer???

Your crank throws are far too big, the stroke shoul be nearer 1", cranks 1/2", maybe you could go to 3/4"/ 1 1/2" stroke, but no more. With that stroke, you will be able to use a longer displacer, it should clear the top and bottom by 2 or 3 mm/ !/8". Ian S C

So basically, I'm doing too much? Trying too hard? I figured the displacer would have to rise to the very top of its travel limit. Maybe that's the problem along with air leakage.

Ok. Well thanks everyone. I've just had my last attempt to buil one if these engines. Turns out I think it all is a sham. I realize now that the engines don't do what they do in the videos because they are just a bunch of glued together cans and wires with a balloon and some fishing string. I'm sorry to say the mechanic at heart on this one really just don't believe this idea works without an electric motor hidden inside. I am offering $20 via paypal for a working model that's decently durable and made of cans.

Insainhouserecords wrote:Ok. Well thanks everyone. I've just had my last attempt to buil one if these engines. Turns out I think it all is a sham. I realize now that the engines don't do what they do in the videos because they are just a bunch of glued together cans and wires with a balloon and some fishing string. I'm sorry to say the mechanic at heart on this one really just don't believe this idea works without an electric motor hidden inside. I am offering $20 via paypal for a working model that's decently durable and made of cans.

Man, that's pretty harsh. I have a working copy of the version our forum host provides plans. Try building one of these instead of the crap aluminum can/balloon thing. Take your time and follow the instructions. Use good materials and tools. There's no reason not to get the walking beam Stirling running. With ice and 2 tea candles mine will run for almost an hour. Slowly and silently. I have a big ole heavy skill saw blade as a flywheel, a glass/graphite power cylinder/piston and bearings from a VCR tape head motor(s). I think there's a pict in the gallery, yep, but here it is again;



This was taken immediately after the engine had ran for the first time. Since then I fitted a heat shield and a water tank to their respective ends.

Did your plans really call for a metal wool displacer for a first engine? Really?

R

Im not trying to be harsh but its really like there had to be a problem one place or another.. For instance, once the crank seemed ok.. The push rods were to long for the balloon. Once I shorten the push rods, the balloon wouldn't travel far enuf up. So I let some slack on the balloon, what's that do? Bind the fishing wire so it can fall properly. It technically is an engine.. In terms of being a cycle.. Idk man. The reason I want the beta type setup is for the application I'm applying it to. I am going to try a different approach with a larger piston version rather than the balloon. But, if anybody might have a clue what the minimum requirments are for a beta can to run, please post them. I got sealed balloon, displacer that's 3/4 size of can, 90' angle on crank arms, balloon with slack and counter weight flywheel.

Insainhouserecords;
What is your application of the stirling engine? Those balloon tin can models are weak and short lived.Might not be the best choice. Go to muddy muddy river how to build a stirling engine on u-tube.He has over 20 step by step videos .You just need to get one these darn fangled machines running so youll have faith again.Dont improvise just follow the plans to the letter the first time.Your frustration will turn into pride and amazement once that puppy starts clanking away.

Coke can models are pretty weak, both in terms of power output and physical strength. There are no electric motors in any of my models.
To be honest, I did wonder if there were motors in these engines when I first started trying to build these engines ( I failed to get my
first few to run).

If you want to see one working, I sell my coke can models on ebay, they're just over $20 inc shipping from the UK (takes a while to get there),
or available as a kit slightly cheaper.

Junkie;
You dont have the water bottle diaphragm stirling engine on your sight. Thats is a relatively simple one to build, holdup and do some work.are you going to have plans or kits for the one you built?

I'm designing an electric generator Guys. I just need my engine to work so I can further my plans. I scraped the coke cans and the whole "middle of can diaphragm" concept for an 2 Tin can "curved PVC pipe on the side" concept. My pro Len with this engine is that without the push rod attached, when heated the balloon diaphragm expands with some force when flywheel is spun but when the push rod is attached the balloon dosent create enuf force to actually "push" with any effort. What part of the engine actually makes the "power" difference? Like, in a combustion engine the size of the piston makes the most decisive difference with cam,timing and compression all added in. With the stirling, is it displacer thickness? Or displacer/crank throw? Please answer these last questions and I believe I can get it to work. The process is what not explained In that sense. I understand the basic process of the motor, heat/cold air exchange but in your opinions what part do you tweak to add somewhat "extra" power?