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General control line discussion => Open Forum => Topic started by: Steve Helmick on February 17, 2017, 10:42:02 AM

Title: Visible Combustion Chamber
Post by: Steve Helmick on February 17, 2017, 10:42:02 AM
Found this YouTube video from a post on facebook, and thought some of y'all would find it interesting. The end of the test run(s) was pretty predictable, but could be easily fixed. I'd guess that the material used is Lexan or Russian equivalent. Could be wrong, as the wife so often points out.  :o Steve

https://www.youtube.com/watch?v=aO5Qkzlo2Kw (https://www.youtube.com/watch?v=aO5Qkzlo2Kw)
Title: Re: Visible Combustion Chamber
Post by: Steve Helmick on February 17, 2017, 10:54:32 AM
"Hello? I want to buy a 1/4-32 Keensert..." That might be a problem, especially in Russia. But up until that (predictable) ending, it was pretty neat, huh?  y1 Steve
Title: Re: Visible Combustion Chamber
Post by: FLOYD CARTER on February 17, 2017, 10:58:22 AM
I WANT ONE!  Need to increase lifespan a bit, though.
Title: Re: Visible Combustion Chamber
Post by: Tim Wescott on February 17, 2017, 01:32:36 PM
Looks kewl.  I think you'd need to make a head out of quartz or sapphire to have it last, and that would be a bit more challenging to machine.
Title: Re: Visible Combustion Chamber
Post by: Steve Helmick on February 17, 2017, 02:03:07 PM
A nice layer of carbon would probably be the end to viewing delights, regardless of what material was used.  S?P Steve
Title: Re: Visible Combustion Chamber
Post by: Phil Krankowski on February 17, 2017, 03:51:09 PM
The exhaust sure looks brighter after sunset.

Phil
Title: Re: Visible Combustion Chamber
Post by: Andre Ming on February 17, 2017, 04:31:01 PM
Obviously the plastic based head isn't capable of enduring the high heat within the combustion chamber, hence the failure of the threads.

I recall days at Fox Mfg that in lower light conditions, within the exhaust port could be seen white hot gasses being exhausted.  Also, the heat created during running on a well fitted engine will be localized from above the exhaust port: Fins/head. During running, the lower portions of the case will actually be cool to the touch. (I've touched bearing areas/etc countless times feeling for vibrations, abnormal heat, etc.)  It's only after shut down that the heat QUICKLY spreads from the head/upper cylinder to the rest of the case.

Glow engines are fascinating pieces of mechanization. I never cease to be amazed at them.
Title: Re: Visible Combustion Chamber
Post by: billbyles on February 20, 2017, 12:23:09 PM
>snip< I'd guess that the material used is Lexan or Russian equivalent. Could be wrong, as the wife so often points out.  :o Steve

https://www.youtube.com/watch?v=aO5Qkzlo2Kw (https://www.youtube.com/watch?v=aO5Qkzlo2Kw)

The video states right at the front that the material is acrylic which is plexiglass.  Very low thermal properties but fine for airplane canopies & other moderate temperature applications.
Title: Re: Visible Combustion Chamber
Post by: Steve Hines on February 20, 2017, 01:05:18 PM
He just needs to use that clear aluminum they use in the Star Trek movie.

Steve
Title: Re: Visible Combustion Chamber
Post by: Brian Hampton on February 20, 2017, 04:12:57 PM
He just needs to use that clear aluminum they use in the Star Trek movie.
Funny you should mention that because something like it is already available ( http://makezine.com/2012/01/17/transparent-aluminum/ ) but mainly used by the military. Actual transparent aluminium has been made recently in the laboratory ( https://phys.org/news/2009-07-transparent-aluminium-state.html ) but could be just a touch impractical :).
Title: Re: Visible Combustion Chamber
Post by: Steve Helmick on February 21, 2017, 02:41:54 PM
The video states right at the front that the material is acrylic which is plexiglass.  Very low thermal properties but fine for airplane canopies & other moderate temperature applications.

Well, no, the video didn't state anything at the front or anyplace else, because there was no dialogue at all. You read the stuff printed on the protective paper covering on the plastic and knew what it meant. I was busy getting rid of the damned banner ad or fiddling with the sound level, most likely.

Same guy made a plastic backplate so he could see what was going on at the crank and rod. Didn't show much but a blurr and a lot of liquid splashing around. I was most interested in seeing if the face of the plastic would be scuffed up by the conrod, but it wasn't, or at least not noticeably.   H^^ Steve
Title: Re: Visible Combustion Chamber
Post by: Brett Buck on February 21, 2017, 02:50:56 PM

Same guy made a plastic backplate so he could see what was going on at the crank and rod. Didn't show much but a blurr and a lot of liquid splashing around. I was most interested in seeing if the face of the plastic would be scuffed up by the conrod, but it wasn't, or at least not noticeably.   H^^ Steve

     About half the Foxes would clear easily, and the other half would dig it away rapidly. Marvin Denny invented the stuffer backplate to keep the rods alive because some of the cases were such that the cylinder axis and the crankshaft axis were not perpendicular. Those with the cylinder bore tilted away from the crankshaft were fine, because the load pushed the conrod tighter up against the crankshaft, but those with the cylinder bore tilted towards the crankshaft pushed the rod off the crankpin. Depending on how close the backplate was to the crankpin, it would either hold it in place, or let it tilt and wear out the conrod. The stuffer was intended to prevent the conrod from sliding off the back the crankpin when the cylinder was tilted "forward" by being a closer fit, and it was anodized to give it a good wear surface.

    Brett
Title: Re: Visible Combustion Chamber
Post by: RandySmith on February 21, 2017, 03:06:49 PM
He just needs to use that clear aluminum they use in the Star Trek movie.

Steve

Or you could use polished  quartz

Randy
Title: Re: Visible Combustion Chamber
Post by: Lyle Spiegel on February 21, 2017, 03:25:08 PM
I believe fused quartz is available in round cylinder shapes and there are techniques for lathe turning. Likely have to use a diamond drill to make glow plug hole, then cut the threads on a lathe. The are machine shops that specialize in quartz machining, Then optically polish to make transparent. I'm sure the cost isn't low.
Title: Re: Visible Combustion Chamber
Post by: billbyles on February 21, 2017, 05:26:24 PM
Well, no, the video didn't state anything at the front or anyplace else, because there was no dialogue at all. You read the stuff printed on the protective paper covering on the plastic and knew what it meant. I was busy getting rid of the damned banner ad or fiddling with the sound level, most likely.

Same guy made a plastic backplate so he could see what was going on at the crank and rod. Didn't show much but a blurr and a lot of liquid splashing around. I was most interested in seeing if the face of the plastic would be scuffed up by the conrod, but it wasn't, or at least not noticeably.   H^^ Steve

It did not state in the (non-existent) dialogue that it is acrylic sheet, but I did read it on the protective sheet where it was printed "12mm acrylic".  And the fact that it stated the material (acrylic) is pretty much all there is to know about it.  It has been a really common material for many years used for airplane canopies, art projects, and many other uses.
Title: Re: Visible Combustion Chamber
Post by: Bruce Shipp on February 21, 2017, 06:56:34 PM
https://www.youtube.com/watch?v=jdW1t8r8qYc&app=desktop


Another cool vid