alpha bellows

Discussion on Stirling or "hot air" engines (all types)
stirling
Posts: 7
Joined: Sat Feb 02, 2013 10:39 am

alpha bellows

Post by stirling » Sat Feb 02, 2013 10:57 am

Hi to all.
I`m new here and want to ask your opinion. i find this site
http://www.akuamarin.com/stirling/ and tried to make same engine but i cant get it working.
My engine without heat is here
Would this concept work or not?
Last edited by stirling on Sun Feb 03, 2013 1:14 pm, edited 1 time in total.

theropod2
Posts: 147
Joined: Tue Aug 16, 2011 5:05 am

Re: Would this work?

Post by theropod2 » Sat Feb 02, 2013 12:22 pm

stirling wrote:Hi to all.
I`m new here and want to ask your opinion. i find this site
http://www.akuamarin.com/stirling/ and tried to make same engine but i cant get it working.
My engine without heat is here
Would this concept work or not?
I think your flywheel is WAY too heavy for your engine, as shown in the video.

Replace that with something that weighs less than 150 grams, and maybe a little smaller diameter, and I bet the engine will run. A thin plywood disc might work. Also, if this is a cold side driven engine you might try salting the ice you are using, or get some dry ice. Balance is also important to getting a Stirling to run. I had to add small weights to the outside of the flywheel on my walking beam until it pulls through the dead part of the rotation better. Is there a plan to add a heated end to get a greater temp difference?

Nice machine work on the crank and stuff. I like the welded-on con-rod offset. Simple, elegant!

Welcome to the forum.

Ian S C
Posts: 2221
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: Would this work?

Post by Ian S C » Sun Feb 03, 2013 12:18 am

I would agree about the flywheel being too heavy, if you take the wheel off the hub, and leave the hub on the crankshaft, that may be about right.
I have a feeling that some araingement should be made on the lower power unit/ bellows for a cell that can be heated quite a bit, because I don't think this will work soully on ice. I'd also make a crank that can have it's stroke adjusted. The whole thing could be usefully built much, much lighter in weight, ie., the crankshaft does not need to be any more than about 1/4" dia. I think it's worth doing a bit of developement work. Ian S C

stirling
Posts: 7
Joined: Sat Feb 02, 2013 10:39 am

Re: Would this work?

Post by stirling » Sun Feb 03, 2013 2:56 am

Thanks for reply`s. I will make the flywheel lighter and maybe balance it. i heated the hot end pipe with gas burner but nothing. Also one problem may be the hot end bellow. If heated it becomes quite soft and deforms.

E: Is the pipe between hot and cold bellow too long? Maybe need to change configuration to make it much shorter

stirling
Posts: 7
Joined: Sat Feb 02, 2013 10:39 am

Re: Would this work?

Post by stirling » Sun Feb 03, 2013 8:36 am

I made some mods. I installed regenerator and hot side heating pipe. Removed heavy flywheel but still nothing. What do you think where`s the problem.
here is video powered by drill to see how its work at high speed
and here is test with heating gas burner to red hot but nothing

I really need some help. What is wrong with this engine???

theropod2
Posts: 147
Joined: Tue Aug 16, 2011 5:05 am

Re: Would this work?

Post by theropod2 » Sun Feb 03, 2013 9:53 am

Are you sure you're turning the crank in the right direction?

R

stirling
Posts: 7
Joined: Sat Feb 02, 2013 10:39 am

Re: Would this work?

Post by stirling » Sun Feb 03, 2013 9:57 am

theropod2 wrote:Are you sure you're turning the crank in the right direction?

R
Same as here http://www.akuamarin.com/stirling/
and i have tried both ways but no result.

fullofhotair
Posts: 265
Joined: Sun Aug 05, 2012 6:28 am

Re: alpha bellows

Post by fullofhotair » Mon Feb 04, 2013 6:23 am

I really love the design.Bellows alpha and your con rod offset. Iam pretty primitive in my own stirlings ,so more of a moral support. All I can think of ,is the system air tight? Does the power piston (bellow) feel pressurized when heated or is it loose like when not running? When you ran it with a drill and no heat does the cold side bellow get cool? I think it should ,stirling refrigeration cycle.I really want to see this stirling running.

stirling
Posts: 7
Joined: Sat Feb 02, 2013 10:39 am

Re: alpha bellows

Post by stirling » Mon Feb 04, 2013 11:07 am

fullofhotair wrote:I really love the design.Bellows alpha and your con rod offset. Iam pretty primitive in my own stirlings ,so more of a moral support. All I can think of ,is the system air tight? Does the power piston (bellow) feel pressurized when heated or is it loose like when not running? When you ran it with a drill and no heat does the cold side bellow get cool? I think it should ,stirling refrigeration cycle.I really want to see this stirling running.
I`m glad you like it. System is airtight ! Maybe the pipe between two bellows are too long or diameter too small?
Perhaps i change hot end bellow to this http://www.firesideware.co.uk/images/bellows/FG1082.JPG more stable in heat i think.

Pipe- total lenght 20"
inner diameter 0.275"
Both bellows when extended long 2.755"
inner diameter 1.968" and 2.559"
Stroke is 1.574" for both bellows

Where is the problem?

fullofhotair
Posts: 265
Joined: Sun Aug 05, 2012 6:28 am

Re: alpha bellows

Post by fullofhotair » Mon Feb 04, 2013 1:55 pm

I had the same idea, sort of, for the power piston . As you stated, the hot end bellows becomes soft and deforms.
The bellows works best when it totally collapses and expands outwards the least.
Look at DIY rubber bellows as power piston. It is just a few lines below your post on this forum. McHamster suggests using woven mesh as structural base to bellows.
If you made the ancient forge bellows as shown in your last post, you could incorporate McHamsters woven mesh and Soeren formula for DIY elastic. My add to this is use aluminum sheets for the walls of the accordion. The sheet of reinforced elastic is glued to the inside of the sheets of aluminum. This would give the least deformation under heat in my opinion.

derwood
Posts: 113
Joined: Sat Dec 11, 2010 10:15 pm

Re: alpha bellows

Post by derwood » Mon Feb 04, 2013 3:56 pm

I attempted a similar project about three years ago and came to the conclusion that the bellows needed to be very rigid. Your engine seems to have no compression at all. I had the same problem. I think the soft bellows absorb any compression. A diaphram may give better results. If your goal is ltd then all of the components need to be very light.

Bumpkin
Posts: 131
Joined: Fri Mar 02, 2012 1:42 pm

Re: alpha bellows

Post by Bumpkin » Tue Feb 05, 2013 5:38 am

Hi stirling. It'd be neat to see a bellows Alpha run, but I think this displacement ratio could only work at very high temperatures and you need a lower expansion ratio.
This L.T.D. Alpha: http://makezine.com/images/07/stirlingengine.pdf seems to have a 1 to 1 ratio, but as you see the pressure can never be higher than the weight of a few inches of water, so there is hardly any compression at all. Also, timing is less critical since the pressure that runs the engine is the rise and fall of the water, which of course, times itself to the expansion/contraction of the air. I wonder if you couldn't accomplish the same thing in your engine by putting some kind of light spring into the connecting rods? Bumpkin

stirling
Posts: 7
Joined: Sat Feb 02, 2013 10:39 am

Re: alpha bellows

Post by stirling » Tue Feb 05, 2013 6:59 am

I think i make cold side bellow stroke shorter and I will try to intsall spring. Maybe change conf like that one http://makezine.com/images/07/stirlingengine.pdf
It makes air transmission faster.

alihureiby
Posts: 6
Joined: Sun Jan 13, 2013 4:17 am

Re: alpha bellows

Post by alihureiby » Wed Feb 06, 2013 11:16 pm

wow , that flywl really big. you can use bicycle for that.

ali

stirling
Posts: 7
Joined: Sat Feb 02, 2013 10:39 am

Re: alpha bellows

Post by stirling » Fri Feb 08, 2013 12:05 pm

I guess it will not work at least with these kind of bellows. Maybe more rigid ones make better choice. Bellows get deformed and absorb compression.

Post Reply