Steel wool displacer piston lenght,now video of start

[larsinist]

See my second post!

[Ian S C]

Larsinist, I don't understand piston house, do you mean cylinder, If so it seems a bit long, the cylinder should be the length of the piston, plus the stroke of the crank, and if the piston actually comes out the end of the cylinder by a mm or two that's OK. Ian S C

[larsinist]

Sorry for my bad english yesterday, was tired.
I need some help to find the right lenght on the displacer can/cylinder and the displacer piston for maximum rpm

Stirling v3.0..jpg (42.83 KiB) Viewed 8278 times

The diaphragm is 41mm in diameter and 3 cm tall,what you think here?

Stirling v3.0.jpg (37.88 KiB) Viewed 8278 times

I use 3 units of 6mm hose to the diaphragm,this should go very good?

Stirling v3.0...jpg (40.41 KiB) Viewed 8278 times

It is two seals for the displacer rod, one brass seal on the down side, and one cork seal in the upper part,and the displacer rod runs free,i use a rim from a bike as a rod,what you mean here?

This is what i have build so far, if i use a 10cm tin-can as a displacer cylinder,and the displacer piston is 3,5cm,will that be ok?, or will a smaller displacer piston as 2cm give me more rpm,or should i go for 4cm piston?
so in other words, i am wonder hos long the steelwool part of the displacer should be for maximum rpm?

Hope you can help me here!!!

Lars

[larsinist]

now i have measured it, the sylinder lenght is 8,5cm, and the piston is 3.5cm long, what do you think about that size then,some said i had large mesurments,if i put a longer sylinder will the diaphragm move more?
my diaphragm moves 8mm under 3 candels now, so i am thinking thats to little?,so thats why i am thinking about a longer sylinder, i have not build the crank yet so i have not tested it!

[Ian S C]

Is this a design that you found on the web, or in a book? If not, I think it might be worth having a look there, and get a illustrated view of an engine that will work. I don't really know much about this type of motor, someone else might come in and help a bit.
I'd say the steel wool displacer should be similar in length to a normal cylindrical metal displacer.

Ian S C

[larsinist]

Thanks for reply ian s c ,the design is my own, i will uppload it to youtube when its running, i think this will be a fast one!!

[Triangle.Stirling]

Hi,

basically ratio between the displacement of the displacer and power piston should be 1.5 : 1
You can choose wich one you set, and then adjust the other so the ratio is right.

the height of the displacer (steelwool) should be as high as possible in the cylinder, if you say the cylinder is 8.5 cm and you have, let's say a 1.5 cm stroke. Then you have 8.5 - 2*1.5 = 5.5 cm space. Add a 0.5 cm gap under and above the steelwool, and the steelwool should be 4.5 cm's. All the air that's under and above the displacer, is of no use, and is called dead air space. This causes a lower efficiency.

What you have to do is decide what you choose, personally i would say a shorter cylinder gives higher speed, but that's just my thougt, because the air doesn't have to travel far then.
Then you could decide the crank throw and with that the displacement, and finally the displacer height. what i've heard is that shorter strokes give higher speeds.

Hope you understand, English is also not my native language. Good luck with the engine!

[larsinist]

[video 425,350]https://www.youtube.com/watch?v=An7AWL0 ... e=youtu.be[/video]

now it starting, but i am sure that i can get more RPM,s out of it, i will try to bild a 4cm piston tomorrow,and i need to adjust the diaphragm rod i think,and the ballon.

[larsinist]

[video 425,350]https://www.youtube.com/watch?v=eAt3AdB ... e=youtu.be[/video] i need to build me a burner,how is that done?

[Triangle.Stirling]

Hi,

Your engine looks really nice! It is already running fast!

You could try and make a alcohol-burner. Just search on youtube for it, it's mostly called a penny-stove. That should do for your engine.

Keep building, and keep posting it here!

Regards,

Krijn

[larsinist]

Thank you, i will build a burner now!, and when thats finished i think i will start building a two sylinder stirling generator,i just need to know a little more about piston and cylinder lenght,cause i should be possible to get much more rpm out of it now, but i think i neew to shorten my piston to 2-2,5cm,i have 3,5cm now, and 8.5cm cylinder!

Thanks all for help, i will keep building

Regards:Lars

[larsinist]

The steel-wool in the cylinder piston is softly layed, so i can move the wool it a litte, should i make it thight??,will that create more/better movment of air?,cause my other stirling had thight rolled steel-wool on the piston, and i allmost got the same rpm, the only real improvment of my last engine is that this one, have a displacer rod instad of a nylon wire, and that itself made it faster.and o also got a bigger diaphragm,but i am not sure that it is good thing

Sorry for all my questions, just some answers would help me alot

[Triangle.Stirling]

what i think you should look at are the dimensions.
You say you want to make your displacer shorter, but that just creates more 'dead air volume', see a few posts above.
What is your crank throw now? Say, the displacers moves 2 cm up and down, and your cilinder is 8,5. Then you can make your displacer 4,5 cm as the biggest, to be safe, and for tolerance, make it 4 cm.
Ratio between displacer displacement (The air you move in the cylinder, with the steelwool displacer) and power piston(balloon) should be 1.5 : 1
You could measure the height the displacers goes, and with the diameter of the can calculate the displacement, i think you could do this. Then you can calculate what the displacement of the balloon should be.

I think it's no problem the steel wool is 'softly layed', that can just improve the regenerator effect i would think.
I think your engine is already turning very fast. I built a can engine first, but mine hasn't run as fast as yours does.
On youtube are also a few video's of can engines running high speed. For example one running around 800 rpm. You could take a look at that one, and maybe look in the comments for more information.

Good luck with building!

[larsinist]

Thank you,for those kind words Triangle.Stirling, i feel motivatet !!

First i wil try answer what Triangle.Stirling asked me about.
My crank throw on the fly-wheel shaft is 1.5,and the cylinder lenght was 8.5
But i have startet to build a new one now, cause i did a big mistake, and testet a 10.5cm can, and a 2cm displacer,with a crank throw on 2 cm, and it would not start!!!!"wrong ratio"
The new tin can stirling is on production now,but i dont have so much time this weekend to make it finished,cause i am on my way to them mountains, to ride some snowmobile, i love the sled!!
I will post some pictures of the new version if some want to see

Now i need to think some Ratio,like Triangle.Stirling wrote here to me
I had some small mechanical problems on the engine in the last video, the displacer rod moved to much sideways when it was at top position,so the fly wheel shaft rod hung/krashed a little.
so i think that i lost many RPM there.

About the diaphragm,if it moves 1cm under one candle,and lets say 2 cm under 2 candles, shout i make the offset after the one candle diaphragm movement, or the 2 candle diaphragm movement, i am thinking that a machine that runs under one candle,will be more effective.
By this i mean that it would move faster and be able to produce more RPM under more candles,if it is adjustet under 1 candle,or would the stroke be to long, and brake the fly-wheel shaft?
Or should i adjust the diaphragm movement, by a 2 candles/tin can burner?????????
Am i thinking weird here??

Sorry for all my questions,and i will learn to write better english,i am from North-Norway, so english is a little hard for me!

Regards:Lars 70degres north

[Triangle.Stirling]

Hi,

I still needed to answer here, so i wrote a little bit on paper, to hopefully make it a bit clearer.



No need for saying sorry, it's nice to help people out. I'm from the Netherlands, so English is also not my native language.

Regards, Krijn (53 Degrees North)