Author Topic: PM Research Engine Number 1  (Read 26114 times)

Offline bent

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Re: PM Research Engine Number 1
« Reply #315 on: August 12, 2021, 04:14:52 PM »
"It's a research project now!"  Yes!

4 hours of hood time?  Wow, you are an expert welder compared to me.  Actually, I have about 8 hrs. in, but 4 of them were repairing/re-doing the welds I made in the first 4 hours...sigh. :embarassed:

Offline gary.a.ayres

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Re: PM Research Engine Number 1
« Reply #316 on: September 16, 2021, 09:57:45 PM »
Excellent work, Stuart.
Just subscribed to your youtube channel.   :)

Offline propforward

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Re: PM Research Engine Number 1
« Reply #317 on: September 17, 2021, 01:50:59 AM »
I saw that! Thank you Gary, and thanks for looking in.

I have been pillar to post for the last month - all good stuff happily, but I still havenít got to try my little TIG brazing R and D project.

I did acquire a new welding table though.
Stuart

Offline TerryWerm

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Re: PM Research Engine Number 1
« Reply #318 on: September 18, 2021, 02:56:39 AM »
Great project, Stuart, and excellent workmanship as well. Looking forward to seeing how your experiment goes.
----------------------------
Terry
Making chips when I can!

Offline propforward

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Re: PM Research Engine Number 1
« Reply #319 on: September 18, 2021, 04:16:49 PM »
Thanks Terry!

One of the other reasons for the experiment is that I am curious to see if I can control the metal build up well enough to consider TIG brazing as a means for boiler construction. Might be easier than trying to flow a whole bunch if tubes in one go.

Or it might be significantly more difficult. Worth a try though.
Stuart

Offline propforward

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Re: PM Research Engine Number 1
« Reply #320 on: November 14, 2021, 12:00:32 AM »
Well OK then. The experiment was not a dismal failure, even if not a complete success.

The valve started thus



I filed the edges to be built up to get them clean, and degreased the part in acetone, then set it up on my weld table in a clamp.



Showing the part the business end of my TIG torch. This is a 3/32 electrode, and a 1/16" would have been more appropriate.



Anyway, as blobby as it looks I did manage to build up the edges with some silicon bronze.



After some initial machining and clean up, I ascertained that the silicon bronze was properly bonded to the part, and it actually machined well.



However, I had not built up the edge quite enough, so after clean up and machining I only gained a small amount on each side. At this point I decided I had put enough time into this. Overall the concept showed signs of success, and I managed to build up the tiny part without completely melting it, so I'm pleased with that - but now I'm just going to move on with life and make a new valve.

Here it is so far:



A simple part really, I'll finish it tomorrow.

I have also been painting the engine - I degreased everything in isopropyl alcohol in a cheap ultrasonic bath, then primed with automotive primer, and let cure overnight.



And then made use of my scale model spray booth to paint it, using a tin of RAF roundel blue enamel paint that I've had since about 1996 or something.





It's perhaps a little brighter than I intended, but overall I quite like it.

So - more progress. I have to figure out a base yet, haven't decided what to do for that.
Stuart

Offline gary.a.ayres

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Re: PM Research Engine Number 1
« Reply #321 on: November 14, 2021, 09:40:11 AM »
Great progress Stuart. Looking good.
Not long to go now...
 :ThumbsUp:

Online MJM460

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Re: PM Research Engine Number 1
« Reply #322 on: November 14, 2021, 10:58:25 AM »
Hi Stewart, nice work on building up a small part.  Shows considerable skill.  But I can understand why it might be better to start again on a relatively simple part instead of having a second go.  An interesting experiment which will have helped develop your technique.

The paint work and colour look good.

MJM460

The more I learn, the more I find that I still have to learn!

Offline Flyboy Jim

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Re: PM Research Engine Number 1
« Reply #323 on: November 14, 2021, 02:59:29 PM »
It's good to see you back at your project Stuart.

I think the paint color looks good. It might not seem so bright to you once you assemble the engine.

Jim
Sherline 4400 Lathe
Sherline 5400 Mill
"You can do small things on big machines, but you can do small things on small machines".

Offline samc88

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Re: PM Research Engine Number 1
« Reply #324 on: November 14, 2021, 06:24:10 PM »
Nice work Stuart, the blue colour looks good

Offline propforward

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Re: PM Research Engine Number 1
« Reply #325 on: November 14, 2021, 06:52:53 PM »
Thanks all, here it is assembled with the new valve. It does run better than before - although perhaps not by much. It has a heck of a knock. not sure where that is. Seems like as the crank reaches and turns past top dead center there is a sort of "notch" to it. Almost like the piston is obstructed from going to max travel, but I can't find anything obstructing it.

<a href="https://www.youtube.com/watch?v=suQPiO8-kmY" target="_blank">http://www.youtube.com/watch?v=suQPiO8-kmY</a>

Anyway, I'm pleased with the colour, and it all fit together, and it runs. It's on the bench chuffing along now, and seems like it is running smoother with some time on it.

In any case, that's it for this engine, other than a base. I'll take what I learned and move on to another, with the plan of taking what I learned and making a better one next time.  :ThumbsUp: :ThumbsUp:
Stuart

Online mikehinz

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Re: PM Research Engine Number 1
« Reply #326 on: November 14, 2021, 07:30:01 PM »
Stuart, excellent work and I love the blue color!  Great job!

I built the same engine a year or 2 ago and I might make a couple of suggestions on the knock you hear.  I'd check the con-rod to crank fit just to make sure it's good.  But I think it's more likely that you've slide valve timing is off just a bit.  I'd try playing with the timing adjustment on the eccentric and in particular try advancing it a bit.  Early admission of the air/stream will tend to 'cushion' the piston travel a bit and might quiet it down and make it run a bit smoother.

Anyway, I hope that helps and again, great work!

Mike
MIke
Wichita, KS, USA

Offline gary.a.ayres

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Re: PM Research Engine Number 1
« Reply #327 on: November 14, 2021, 07:36:41 PM »
 :ThumbsUp: :ThumbsUp: :ThumbsUp: :cheers: :ThumbsUp: :ThumbsUp: :ThumbsUp:

Offline propforward

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Re: PM Research Engine Number 1
« Reply #328 on: November 14, 2021, 07:49:04 PM »
Thank you both!

Mike I just tried what you suggested, and that helped a lot. Also - the knock is being accentuated by the fact the engine is sitting on the bench, I just lifted the block up and sat it on a couple of pieces of rubber sheet and it is way quieter, but it runs slower and at lower pressure now I adjusted the timing. I think the notch I feel is being caused by the crankshaft, which is not straight. It moved when I released the central web support when machining it, and I think that is the culprit, it binds as it goes top and bottom dead center - just a little bit.

Anyway, with that improved running I'm much happier. When I get it on a display base I'll shoot one more showcase vid.

Thanks so much for the input and comments!  :ThumbsUp: :ThumbsUp: :ThumbsUp: :ThumbsUp:
Stuart

Offline propforward

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Re: PM Research Engine Number 1
« Reply #329 on: November 14, 2021, 08:22:34 PM »
OK, one more and done until the showcase. :D

<a href="https://www.youtube.com/watch?v=r_fkghSZOnA" target="_blank">http://www.youtube.com/watch?v=r_fkghSZOnA</a>

« Last Edit: November 14, 2021, 09:10:01 PM by propforward »
Stuart