Author Topic: Look what I made. (Read 6735 times)

freakazoid · « **on:** April 09, 2014, 11:39:15 PM »

So a friend was looking up model engines and we came across this type of engine called a stirling engine, https://www.youtube.com/watch?v=wGRmcvxB_dk It's pretty interesting. Well on further research I found that there is a company called Bohm, there are diaeresis over the "o" for maximum Germanness, they make stirling engine kits and complete builds. There is a site called www.ministeam.com that sells them here so I ended up getting the HB11 model kit. Got it in earlier today and finished it not to long ago. This thing is really cool. Here are some pictures!

Before,

After,

Here are two videos of it I made!
This is the test run, https://www.youtube.com/watch?v=DsuDoOt3GhU it didn't work out so well as you can read in the description.
This is it running, https://www.youtube.com/watch?v=YQJpi2unFpc

You can even make them out of a few things lying around the house, or garbage can. https://www.youtube.com/watch?v=RzW0--FMbVg

What I really want to get is what is called a flame eater. It also goes by many other names, flame licker, flame sucker, flame gulping, vacuum engine, and popper. https://www.youtube.com/watch?v=vkaz9rDJWQ4 https://www.youtube.com/watch?v=5_hFqfstJAU Ministeam has some, but the style I want isn't in kit form. They have a type made by Bohm that you can also get as a kit but I would much rather have the other version. I'm just going to have to get a lathe/mill and build one myself. You can find plans to build them, http://www.projectsinmetal.com/free-metalworking-project-plans-the-flame-eater-vacuum-engine-by-jan-ridders/

Here are two videos from a guy who builds his own, https://www.youtube.com/watch?v=E5UuGzx9pug https://www.youtube.com/watch?v=Z7v69zVGycQ Practically works of art.

TommyGunn · « **Reply #1 on:** April 10, 2014, 12:38:32 AM »

Awww, that's SO cute.

gunsmith · « **Reply #2 on:** April 10, 2014, 03:07:46 AM »

Quote from: TommyGunn on April 10, 2014, 12:38:32 AM

Awww, that's SO cute.

LOL...

pretty neat thing to have on your desk etc

geronimotwo · « **Reply #3 on:** April 10, 2014, 07:14:22 AM »

elegant design. where does the steam come from, ie, source of water?

RoadKingLarry · « **Reply #4 on:** April 10, 2014, 08:08:48 AM »

Heat engine, no steam.

http://en.wikipedia.org/wiki/Stirling_engine

freakazoid · « **Reply #5 on:** April 10, 2014, 08:42:14 AM »

Quote from: geronimotwo on April 10, 2014, 07:14:22 AM

elegant design. where does the steam come from, ie, source of water?

An elegant weapon, for a more civilized age.

K Frame · « **Reply #6 on:** April 10, 2014, 01:30:05 PM »

Friends of mine have a Stirling engine on their wood stove...

dogmush · « **Reply #7 on:** April 10, 2014, 01:40:52 PM »

Well thanks for costing me several hundred dollars......

Balog · « **Reply #8 on:** April 10, 2014, 01:41:27 PM »

Quote from: Mike Irwin on April 10, 2014, 01:30:05 PM

Friends of mine have a Stirling engine on their wood stove...

To turn a blower I would assume? That's a clever idea to circumvent pellet stoves dependence on electrical power...

K Frame · « **Reply #9 on:** April 10, 2014, 01:43:08 PM »

Sorry, they have a Stirling engine FAN on their woodstove.

Helps circulate air in their living room, which is kind of long and narrow.

Balog · « **Reply #10 on:** April 10, 2014, 01:44:36 PM »

Quote from: Mike Irwin on April 10, 2014, 01:43:08 PM

Sorry, they have a Stirling engine FAN on their woodstove.

Helps circulate air in their living room, which is kind of long and narrow.

That is a very very smart idea. Did they DIY it, or is that commercially available?

mtnbkr · « **Reply #11 on:** April 10, 2014, 01:52:28 PM »

Quote from: Balog on April 10, 2014, 01:44:36 PM

That is a very very smart idea. Did they DIY it, or is that commercially available?

They're commercially available.

Chris

RoadKingLarry · « **Reply #12 on:** April 10, 2014, 03:54:39 PM »

Reviews I've seen from the woodstove community don't give the little heat powered fans very high marks, not much power.

freakazoid · « **Reply #13 on:** April 10, 2014, 04:04:48 PM »

Quote from: dogmush on April 10, 2014, 01:40:52 PM

Well thanks for costing me several hundred dollars......

No problem.

What did you end up getting?

KD5NRH · « **Reply #14 on:** April 10, 2014, 05:21:06 PM »

Quote from: RoadKingLarry on April 10, 2014, 03:54:39 PM

Reviews I've seen from the woodstove community don't give the little heat powered fans very high marks, not much power.

Power depends on heat differential. If the cold side is over the stove too, I'd imagine it's not really working to its potential. Now, if you could bring in some outside cold for it, it should improve things greatly.

Tallpine · « **Reply #15 on:** April 10, 2014, 05:36:22 PM »

Wonder if you could use a lense and/or mirror to run it off of sunshine ?

Nick1911 · « **Reply #16 on:** April 10, 2014, 05:38:06 PM »

Quote from: KD5NRH on April 10, 2014, 05:21:06 PM

Power depends on heat differential. If the cold side is over the stove too, I'd imagine it's not really working to its potential. Now, if you could bring in some outside cold for it, it should improve things greatly.

Hmmm... small copper heat-pipe leading out the roof?

230RN · « **Reply #17 on:** April 11, 2014, 11:52:39 AM »

Quote from: freakazoid on April 09, 2014, 11:39:15 PM

So a friend was looking up model engines and we came across this type of engine called a stirling engine, https://www.youtube.com/watch?v=wGRmcvxB_dk It's pretty interesting.

What altitude are you at? I built one from my own plans and couldn't get it to work up here (~6000 ft). I blamed it on the thin air, but maybe it was just crappy design and workmanship on my part --tin cans and whatnot as materials..

(Power also depends on the density of the working medium. They can't work at all in a vacuum, and some high-efficiency types use helium at around 3000 psi as a working medium. The air up here is only about 12 psia. Helium has high "heat capacity" and high fluidity.)

((And if nobody else has answered the question, yes, they will run on focused sunlight.))

Mebbe I shoulda built a flame sucker.

https://www.youtube.com/watch?v=s_WyzBy3RC8&feature=player_detailpage

Terry, 230RN

REF (Altitude v pressure):
http://www.sablesys.com/baro-altitude.html

freakazoid · « **Reply #18 on:** April 11, 2014, 01:51:36 PM »

I'm in El Cajon, CA, so right on the coast. Also brought it on board the ship and started it, so only a few feet above the ocean.

I would like to try building one of the flame suckers, maybe I'll get a mill/lathe after next deployment and do it.

AJ Dual · « **Reply #19 on:** April 11, 2014, 02:39:33 PM »

Quote from: Grumpy Old Man on April 10, 2014, 05:36:22 PM

Wonder if you could use a lense and/or mirror to run it off of sunshine ?

In theory, yeah.

There's solar farms working off the principle.

http://www.solarpowerworldonline.com/2010/01/solar-driven-parabolic-dish-farm-opens/

230RN · « **Reply #20 on:** April 14, 2014, 09:36:42 AM »

Of further interest for those wishing to understand the rather simple principles involved:

http://en.wikipedia.org/wiki/Stirling_engine

Basically, imagine a closed cylinder engine with a rather large volume on top of the cylinder. If you heat the air in that volume, it will expand, pushing the piston down. If you cool the air in that volume, it will contract, pulling the piston back up.

You could do this manually, applying heat to the top, then cold. Naturally, this would cause the piston to move up and down.

But it is much easier to have a loose fitting "extra" piston in that volume which just shuttles the air between a hot portion of the volume and a cold portion of the volume.

Of course, the timing has to be right, so the air gets cooled when the power piston is at the bottom of its stroke, and heated when it is the top of its stroke.

Thus, animated GIFs showing all this going on:

http://en.wikipedia.org/wiki/File:Alpha_Stirling.gif
http://en.wikipedia.org/wiki/File:Beta_stirling_animation.gif

The one I built that didn't work was of the beta type. One major problem was making good seals with low friction. I should have foreseen that before I designed it, though, so naturally, I had to blame the altitude instead of my poor engineering skills. I later thought of using rollsock seals, but that would have involved mechanical processes beyond my capabilities.

As I mentioned, this will not work at all if there is no air (working medium) in the hot and cold chambers --that is, with a total vacuum. So, projecting from this idea, it will work better and better as the working medium total pressure (density) is greater and greater.

The article also shows Stirling engines being heated by solar dishes, as I touched on previously.

I understand, but cannot document right now, that nuclear heat is used to run Stirling engine generator-sets for satellites and space probes and the like, with helium at 3000 psi instead of air for the working medium.

Something I didn't know is that the more modern developments of the Stirling operating principle were made by Phillips so they could sell more radios! Interesting, eh?

Terry, 230RN

AJ Dual · « **Reply #21 on:** April 14, 2014, 12:34:11 PM »

Quote from: 230RN on April 14, 2014, 09:36:42 AM

I understand, but cannot document right now, that nuclear heat is used to run Stirling engine generator-sets for satellites and space probes and the like, with helium at 3000 psi instead of air for the working medium.

Yep. Yet another birdman project.

K Frame · « **Reply #22 on:** April 14, 2014, 01:01:34 PM »

Quote from: Balog on April 10, 2014, 01:44:36 PM

That is a very very smart idea. Did they DIY it, or is that commercially available?

As far as I know they bought it at some fireplace shop or some such. I've seen them advertised on places like hearthnet.com

freakazoid · « **Reply #23 on:** April 14, 2014, 09:31:20 PM »

Quote from: 230RN on April 14, 2014, 09:36:42 AM

Of further interest for those wishing to understand the rather simple principles involved:

http://en.wikipedia.org/wiki/Stirling_engine

Basically, imagine a closed cylinder engine with a rather large volume on top of the cylinder. If you heat the air in that volume, it will expand, pushing the piston down. If you cool the air in that volume, it will contract, pulling the piston back up.

You could do this manually, applying heat to the top, then cold. Naturally, this would cause the piston to move up and down.

But it is much easier to have a loose fitting "extra" piston in that volume which just shuttles the air between a hot portion of the volume and a cold portion of the volume.

Of course, the timing has to be right, so the air gets cooled when the power piston is at the bottom of its stroke, and heated when it is the top of its stroke.

Thus, animated GIFs showing all this going on:

http://en.wikipedia.org/wiki/File:Alpha_Stirling.gif
http://en.wikipedia.org/wiki/File:Beta_stirling_animation.gif

The one I built that didn't work was of the beta type. One major problem was making good seals with low friction. I should have foreseen that before I designed it, though, so naturally, I had to blame the altitude instead of my poor engineering skills. I later thought of using rollsock seals, but that would have involved mechanical processes beyond my capabilities.

As I mentioned, this will not work at all if there is no air (working medium) in the hot and cold chambers --that is, with a total vacuum. So, projecting from this idea, it will work better and better as the working medium total pressure (density) is greater and greater.

The article also shows Stirling engines being heated by solar dishes, as I touched on previously.

I understand, but cannot document right now, that nuclear heat is used to run Stirling engine generator-sets for satellites and space probes and the like, with helium at 3000 psi instead of air for the working medium.

Something I didn't know is that the more modern developments of the Stirling operating principle were made by Phillips so they could sell more radios! Interesting, eh?

Terry, 230RN

One of the videos I linked to in the OP is instructions on building one from everyday materials.

230RN · « **Reply #24 on:** April 15, 2014, 01:31:08 PM »

^ I noticed that, and thanks. Too bad I no longer have my shop. I wouldn't mind trying another one based on someone else's plans. As I said, mine was cobbled together from tin cans and the like.

I still think the altitude had a lot to do with my failure, though, and not just because of the working medium pressure/density (air), but lack of enough cooling of the "cold end" --again, due to the thin air.

Anyone else have one at high altitudes that worked?

(I'd like to point out that many of those stove circulating fans run off Stirling engines might be used in cabins at higher altitudes, which could account for the complaints about their lack of efficiency.)

Terry, 230RN

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Author Topic: Look what I made. (Read 6735 times)