Author Topic: A different opposed piston engine  (Read 84985 times)

Offline Johnmcc69

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Re: A different opposed piston engine
« Reply #330 on: March 29, 2014, 05:47:08 PM »
FANTASTIC Brian!

 John

Offline Alan Haisley

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Re: A different opposed piston engine
« Reply #331 on: March 30, 2014, 02:52:53 PM »
 :cartwheel:

Alan

Offline Heffalump

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Re: A different opposed piston engine
« Reply #332 on: March 31, 2014, 02:30:42 PM »
Haha that's great! I love the machine there..

Offline Brian Rupnow

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Re: A different opposed piston engine
« Reply #333 on: April 21, 2014, 11:00:42 PM »
Just a final post to end off this thread in case someone finds it in the future, The engine ran well, but the crankshaft was not straight, and consequently the aluminum wheel on the front of the engine danced around in a very unsightly manner. I have removed the crankshaft and replaced the "bad end" and now it runs true.

Offline b.lindsey

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Re: A different opposed piston engine
« Reply #334 on: April 22, 2014, 12:40:22 AM »
That sure did the trick Brian. You should be very happy with it now!!

Bill

Offline Brian Rupnow

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Re: A different opposed piston engine
« Reply #335 on: April 22, 2014, 01:06:12 AM »
Thanks Bill. I am happy with the results, and it has got me thinking about the method I may use for future crankshafts I may build.

Offline Brian Rupnow

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Re: A different opposed piston engine
« Reply #336 on: February 26, 2015, 02:52:38 PM »
To revive an old thread and cry "mea culpa" to all who suggested an outboard support for the cantilevered stub shafts. I haven't really ran the engine much at all since I built it and straightened the crankshaft. Last week when I was searching for an engine to run the model buzz saw I built, I noticed a strange phenomenon. Although the cantilevered stub-shafts didn't visually deflect when the engine was running, they must have at some level, because the bolts through the main backplate which anchored the stub shafts in their pockets in the main engine backplate would loosen off after about 10 minutes running, no matter how much they were tightened.Then the cantilevered stub shafts would indeed move all over the place. This presented a major pain in the butt, because I had to remove the large diameter flywheel on the back side of the engine to get at the bolt heads and re-tighten them. After removing the flywheel twice to tighten the bolts, I decided that yes, everyone who suggested an outboard support for the cantilevered shafts was right and I was wrong. So--I redesigned the removable front plate and added a couple of "extensions" with pockets to hold the extended end of the no longer cantilevered stub shafts. I made new, longer stub shafts and drilled the extended ends for #8-32 bolts. This actually entailed a couple of days work and almost total disassembly of the engine, however the engine is now solid as a rock when it runs, and I filled up a couple of horribly cold winter days with something to do.

Offline crueby

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Re: A different opposed piston engine
« Reply #337 on: February 26, 2015, 10:10:47 PM »
Hey Brian - not sure if you have explored this on other threads or not, but have you ever experimented with a double-acting IC engine? It would have to run the piston rod through a sealing bushing the second cylinder below the piston, and valving would be interesting, but could be a really slick combination of a double-acting steam design with a IC engine - twice the pistons in half the space...
Beyond my abilities, but seems like a great challenge you could tackle!

Offline Brian Rupnow

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Re: A different opposed piston engine
« Reply #338 on: February 26, 2015, 10:40:29 PM »
Crueby--I haven't done it, but Jan Ridders has with his "two stroke puppy" and its larger brother, ( I can't remember what it is called.) I know it works, I have seen the video of it running, and I think one of our Australian friends has built it as well. For a demo engine, it works great. For any kind of long term duty though, the by-products of combustion mess up the surface of the rod where it slides thru the seal at one end of the cylinder and destroy the seal.--.-Brian
« Last Edit: February 27, 2015, 12:08:14 AM by Brian Rupnow »

Offline kvom

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Re: A different opposed piston engine
« Reply #339 on: February 27, 2015, 12:17:21 AM »
I was thinking this engine could be modified to run on air with a suitable valve arrangement.

Offline gipetto

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Re: A different opposed piston engine
« Reply #340 on: August 31, 2023, 12:29:00 AM »
I had a go at bending some brass tubing, but after the third kink I gave up in disgust and used some solid brass that I had to make 1/4" diameter "lines" with a .080 hole drilled full length.

My grandfather owned a steam traction engine at one point, and it used copper tubing. There was an art to bending it without introducing kinks. He would fill sand into the copper tube, then heat the tube and bend it while hot into coils. the sand would stop the tubing from kinking. The sand had to be dry as any moisture within would flash to steam inside the tube causing an explosion.

 

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