Stirlingengineforum.com

Or you could try a much shorter tin and a balsa wood displacer.
Shorter tin = less air space = more pressure on the rubber diaphragm. Disposable latex gloves, the thicker mechanics type are used on some engines.

See this one here for the shorter tin version:
http://myfordboy.blogspot.com.au/p/myfo ... ngine.html

I will try a shorter version. Thank you. I figured the taller the can the taller the displacer, but some part of the physics aren't working for me. I think I haven't had a good explanation of how larger the displacer should actually be in comparison to how long the crank throw should be. There really should be a magic formula that achieves success. Like it shouldn't matter if the stirling engine is the size of a house as long as the displacer is x size to the crank throw. At least it seems.

Go to the Myfordboy web site indicated by Hopper, read it, and fully understand it, get the plans (free), or go to boydhouse site and do the same, follow the instructions and you will have a working engine, then you can change things to see if they work better or worse (one thing at a time). The most important thing you need is patience, don't hurry, take care, you can do it. Ian S C

That sound like a good idea. I will try this approach. I just don't understand why it's so hard when it should be able to work with simple ease. I mean, if it holds air, displaces air, and it at 90' crank, it should work.

What do you think determines the amount of "power" obtainable? Amount of temputure change, displacer size, crank throw measure or what's your best guess?

Insainhouserecords wrote:What do you think determines the amount of "power" obtainable? Amount of temputure change, displacer size, crank throw measure or what's your best guess?

All these things contribute to power, but they must be in the right proportion. Size of the diaphragm plays an important part to. More area = more force.
But if you follow an established, proven design, the two most important factors determining power output are air leakage and friction.

If someone will please post the plans for one of the can engine designs, I will leave this forum alone and let you guys be. I have been to the myfordboy website and the stirling builder website and there is no measurements or printable layouts of any kind. Why point people in the direction of vague plans? It's really simple. Please list the plans here step for step so everyone can see and discuss them along with the measurements. If one of you guys actually has a can engine than why is this information so withheld? Look at I like this, if your can engine works and the displacer is x size to the pressure can, than the crank throw is x size to the displacer travel. In turn your diaphragm travels x amount to your crank throw for the displacer. All this is simple physics that can be applied to any application for a stirling engine. These is science are called the "magic numbers". A formula that transcends into any engine design as long as the formula is multiplied by scale. With that said one more question arises... Why am I the only one here who sees this and also the only on who can't make it work? Please post plans with measurements.. Copy and paste if you have too, but copy and paste what you could manage to use.

Anymore demands?

It's not like that. This is a forum, if you don't want to help the cause... Just don't. Only certain intellectuals could fathom the idea of a working formula... Dude. What I'm tryin to do will help all of the stirling engine scene.

First of all Dude, When you scale up, the proportions change due to heat exchange issues. There are also many other factors which make it impossible to just multiply by 10 and get 10 times more power.

My plans have all of the dimensions on them. If there's one missing, let me know and I'll add it.
http://www.scraptopower.co.uk/can-stir ... ing-engine

Not in that aspect. What I mean is that these guys (Jim Larson,myfordboy) didn't just glue part together 1000 times before their respective engines worked and their plans where drawn out. There is a formula and there is logic to what I am saying whether or not you can see it. I mean come on guy, there are 200+ engine working on YouTube and a multitude of plans but not one person will "show their work" as in the math used to decide crank throw, displacer size, etc etc. compared to the pressure chamber they chose.

And to junkie, your engine was the first 4 I tried to make. Using different measurements that you don't provide. Like crank placement location exacts and balloon travel in respect of crank throw. My first couple of problems where that the wire pushrods would "push and pull" too much on the balloon, I figured it was improper crank throw for the push rods. So I made a new crank and it seems there is no median on the tension. You can attach the crank to the pushrods in up or down position and no matter what there's a bind. Up crank position requires longer pushrods and down crank position requires shorter pushrods, either way there is a problem with the end result. If you Make the diaphragm attach to the crank in crank down position, when the crank is turned there is pressure from the balloon tension on the crank and if you attach in crank up position, then when the crank is spun the pushrods(bottle cap)jam too far down into the balloon and bind up unless forced which bends the wires and tears the cans. The balloon never seems to travel the right distance either way without too much slack. That's why I want to just grab some more cans and apply the math myself to build one of my own design.

I have suggested this before in this thread. Stop wasting time.

Look at the free plans available from the man that hosts this very forum.

HERE (<that's a link) is the page that will take you to those plans, with all the measurements. I know for a fact these engines work. You want a set of real plans? You want dimensional drawings? If you can not build the engine therein and get it to run I can't help.

Frankly I find it a little offensive that instead of even looking for the link above you continue along this path of negativity. We've had the forum working for several years now, and almost all of us have built a working engine or 4. If you're dead set on building a soda can engine without measurements go ahead. Can you actually expect us to figure out your engine for you? Willingness to help only goes so far.

My free advice is to at least look at the walking beam engine. Get that to work and then build one to eliminate the beam. Then build one with a glass center section.

R

I'm not being negitive the guy with the negativity seemed to not get my questions. I am going to just follow thru with someone else's design. It's just hard for me to figure how some of these big name stirling guys, got their designs... If they built them themselves from scratch they had to have a idea of what the dimensions where going to have to be.. But how? Guess work? Doesn't seem very logical.