Author Topic: Stew Hart's Popcorn Engine  (Read 245 times)

Offline ImIndoors

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Stew Hart's Popcorn Engine
« on: January 12, 2018, 10:40:20 PM »
At last I have the Popcorn engine finished (sort of!).
After reassembling it following stripping and painting I discovered that I had somwhow managed to bend the piston rod and it no longer moved freely or lined up with the crosshead.  My first attempt at a replacement failed when I cut an M4 thread on it and found that the brand new thread die I used chewed a thread which was horribly undersize and barely even made contact in the crosshead.  The second new rod worked.  Also the whistle valve, which held air when I made it, now doesn't for reasons unknown so I hope that will be fixed when I replace the bronze ball in it with a nitrile one.   
 
Anyway,a video:


I think I also need to slow down the governor flyballs a bit which I can do by reducing the diameter of the drive pulley.

Jim
The person who never made a mistake never made anything.

Offline Kim

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Re: Stew Hart's Popcorn Engine
« Reply #1 on: January 12, 2018, 11:01:39 PM »
That is a very nice looking engine, Jim.
Love the whistle!
Kim

Offline zeeprogrammer

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Re: Stew Hart's Popcorn Engine
« Reply #2 on: January 12, 2018, 11:11:22 PM »
Beautifully done and I love the whistle.  :ThumbsUp:

This has been at the top of my project list for some time.

Did you scale the plans?
Are the plans the same as the ones Julius posted some time ago?
Carl (aka Zee) Will sometimes respond to 'hey' but never 'hey you', whistles, and certain dinner bells.
"Found a peanut."
To work. To work. Zee-The Thread Trasher.

Online Gas_mantle

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Re: Stew Hart's Popcorn Engine
« Reply #3 on: January 12, 2018, 11:46:09 PM »
What a great little engine Jim, looks to be a very smooth runner.

I like your attention to detail with added embellishments such as the attractive whistles and the valve knob.

One to be proud of  :)

Online b.lindsey

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Re: Stew Hart's Popcorn Engine
« Reply #4 on: January 13, 2018, 12:09:58 AM »
Beautiful Jim. And the finish is wonderful. I do agree the flyballs should be slowed some...they are really dancing, but that's a minor issue. Well done.

Bill

Offline Brian Rupnow

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Re: Stew Hart's Popcorn Engine
« Reply #5 on: January 13, 2018, 01:16:45 AM »
Very nice. I built one of those just after Stu posted the plans a few years ago. A great little engine. I like the governor.---Brian

Offline sbwhart

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Re: Stew Hart's Popcorn Engine
« Reply #6 on: January 13, 2018, 06:08:39 AM »
Excellent job Jim:- you've got a lovely finish, and it run and sounds really well to, the whistle has a good tune.

If any one wants a copy of my plans all they have to do is drop me a PM.

Cheers
Stew

A little bit of clearance never got in the way

Offline ImIndoors

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Re: Stew Hart's Popcorn Engine
« Reply #7 on: January 13, 2018, 12:53:27 PM »
Aw, shucks.:embarassed:  Thanks for the kind comments everybody and special thanks to Stew for providing the drawings.

Zee.  I built it from Stew's drawings which he kindly sent me.  I can thoroughly recommend his designs (this is the second of his I've built) which he generously offers to all, just send him a PM.

Now it's on with Ray Hasbrouck's number 3 engine, which has a rocking valve system, then a Hit'n'hope miss.

Jim
The person who never made a mistake never made anything.