Search found 28 matches

by tmk
Fri May 18, 2007 8:31 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: increasing displacer 'dwell' time
Replies: 14
Views: 21342

yeah like a router in a piece of wood was exactly how i would make it. Then just a small wheel with a good bearing that fits inside the track with just a tiny bit of room all around.. it will sometimes roll on the 'inside' edge and sometimes on the 'outside' one. Perhaps a small lego wheel or someth...
by tmk
Thu May 17, 2007 8:54 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: 'cookie' engine diary
Replies: 7
Views: 10013

I'll put up a webpage a little later, i just wanted to share my progress. I see you're in california... if you're in the bay area, the maker faire is this weekend.. There will be a guy who ran a company that built stirlings there http://makerfaire.com/ http://makerfaire.com/pub/e/272 - stirling exhi...
by tmk
Thu May 17, 2007 12:03 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: 'cookie' engine diary
Replies: 7
Views: 10013

'cookie' engine diary

I'm building a stirling engine made out of a cookie tin, chicken wire, aluminum foil, and whatever else i find lying around the house. I'll update this thread as i make progress. Since the body is a cookie tin (about 8" in diameter by 4" tall), i'm naming this one 'cookie'. Perhaps i'll re...
by tmk
Wed May 16, 2007 11:00 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Unique Scuderi IC engine
Replies: 2
Views: 5827

your models are really quite well done. If you don't mind sharing, where do you get the parts? Do you machine them yourself? Is there some sort of small engine supply shop that sells all these little bits and pieces? the gearing and tooth belt in particular seem like they would be hard to come by. t...
by tmk
Wed May 16, 2007 9:23 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: increasing displacer 'dwell' time
Replies: 14
Views: 21342

..

I was thinking that a weight to move the displacer would probably be counter-productive, as you want the displacer to move as freely as possible with as little effort as possible. every bit of energy required reduces the efficiency of your engine. At the same time though, the weight of the displacer...
by tmk
Fri May 11, 2007 2:53 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: increasing displacer 'dwell' time
Replies: 14
Views: 21342

or even simpler..

Since for the displacer, all you need to do is move it up and down, and it's not a power-producing part, you could just make a 'guide' on the flywheel, shaped such so that it would push the displacer up and down as it rotated. picture, thousand words, etc: http://home.comcast.net/~nufan_wfk/stirling...
by tmk
Thu May 10, 2007 2:39 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Easy way to make a piston
Replies: 8
Views: 15578

Easy way to make a piston

Just thought i'd share with the group here. i am (slowly) building a stirling, and i was in need of a piston. The copper + epoxy idea seemed ideal, but copper pipe is expensive, and i don't know any plumbers i can bum scraps off of. Besides, i don't have a good way to push them out once the epoxy is...
by tmk
Thu May 10, 2007 2:18 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Compression cycle.. worthwhile?
Replies: 7
Views: 9647

ahh.. i must have misunderstood

I was under the impression that the '90degrees out of phase' orientation of the power piston vs the displacer actually was meant to cause some 'real' compression, for example take this animation: http://www.grc.nasa.gov/WWW/tmsb/stirling/animation/anim_6.html The displacer is shown to be stationary ...
by tmk
Thu May 03, 2007 8:51 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: Compression cycle.. worthwhile?
Replies: 7
Views: 9647

... what if

The compression stroke happens when the piston is moving inwards, but in the meanwhile the air temperature in the engine is decreased (by most of the air being on the cold side). What if the timing was changed slightly, and we could move the displacer quickly at set points in the cycle, rather than...
by tmk
Wed May 02, 2007 8:39 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: Compression cycle.. worthwhile?
Replies: 7
Views: 9647

Compression cycle.. worthwhile?

I'm still just learning about stirling engines, and i'm curious as to the need for the compression cycle. As I understand it, the compression cycle takes power that you have previously generated (at < 100% efficiency) and uses it to compress/expand air (at < 100% efficiency) which either heats it wh...
by tmk
Wed May 02, 2007 8:29 am
Forum: Stirling and "Hot Air" Engine Forum
Topic: increasing displacer 'dwell' time
Replies: 14
Views: 21342

thanks..

Thanks for the comments. My plan is to try and build one of these simple LTD type engines and swap out the flywheel etc with the gearing type mechanical linkages and compare how it works. I would *expect* that the gearing models would rotate more slowly but have higher torque, but i'm no M.E. nor st...
by tmk
Tue May 01, 2007 11:15 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: increasing displacer 'dwell' time
Replies: 14
Views: 21342

.. and while we're on the topic, a clever circuit

Also, here's a clever electronic circuit that could be used to move the displacer at the correct time. http://home.comcast.net/~nufan_wfk/stirling/stirling-electronic.jpg Explanation: the switches are momentary, normally open switches. They will be 'connected' when the power piston reaches the end o...
by tmk
Tue May 01, 2007 9:47 pm
Forum: Stirling and "Hot Air" Engine Forum
Topic: increasing displacer 'dwell' time
Replies: 14
Views: 21342

increasing displacer 'dwell' time

Hi folks, new to this forum, nice to meet you all I haven't built an engine yet, so please bear with me :) I've been thinking about how to increase the displacer dwell time, and i came up with a few ideas: http://home.comcast.net/~nufan_wfk/stirling/stirling-options.jpg left: default engine mid: 2 g...