walschaerts valve gear issues

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NP317
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Re: walschaerts valve gear issues

Post by NP317 »

VGC wrote: Sun Jan 30, 2022 3:55 pm
NP317 wrote: Sun Jan 30, 2022 1:25 pm [snip]
Same time??? See valve piston inlet and outlet positions (e.g. red lines for front cylinder chamber) in the diagram below.
Of course not at the same time, thus my reference to the Johnson Bar position which changes those relationships.
I was trying to simplify the discussion to present the basics of Inside vs Outside admission.

And Thank You for your specific reference to the detailed operation. I love those diagrams!
RussN
VGC
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Re: walschaerts valve gear issues

Post by VGC »

In my opinion, this is the only diagram you need for designing a really good valve gear ;-)
And some years ago, four points of this diagram were enough for me to restore the full power of a small 600 mm gauge locomotive with Hackwort valve gear by dimensioning a new bar.
VGC
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Re: walschaerts valve gear issues

Post by VGC »

VGC wrote: Sat Jan 29, 2022 4:22 am I could offer a test if you can wait some time for the result:
Send me the valve piston positions in piston dead center position and the valve and piston position when steam inlet closing, each for forward and bakward riding, and I try to tell you what to change on your valve gear.
trainman154 wrote: Sat Jan 29, 2022 5:28 pm ok I will get pictures of the valves in the positions that you asked for and I will post them here when I am able to.

Just a note that my eccentric is actually "keyed" in place so to speak with a set screw so I can not currently move the position of the eccentric.

Thanks
What I mean is the measured position. It is not important what the reference (zero point) is, if it is always the same one. You also can measure the position of a rod mark outside of the cylinder.
Pictures can be useful but will not be exact enough.
Do it on both sides of the locomotive.

So when do you think you can post this?
VGC
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Re: walschaerts valve gear issues

Post by VGC »

The above offer will end on May 14, 2022.
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Harold_V
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Re: walschaerts valve gear issues

Post by Harold_V »

Likely a non-issue. That individual hasn't been on the board since the end of January.
H
Wise people talk because they have something to say. Fools talk because they have to say something.
VGC
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Re: walschaerts valve gear issues

Post by VGC »

Nevertheless I like to be clear. Perhaps he sometimes reads "from outside".
VGC
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Re: walschaerts valve gear issues

Post by VGC »

He had asked for further help after not responding here. I think I will answer his next question with a link to this topic here. Seems to be a rather impolite person...
Online program for valve gear design:

ValveGear Constructor [EN]

Image

With automatic pre-optimization, DXF export, etc.
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