Author Topic: Trevithick  (Read 9894 times)

Offline Jasonb

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Re: Trevithick
« Reply #15 on: August 27, 2020, 07:10:18 PM »
take up one of the other offeres in this thread that's the drawings I'm looking at, also has the cylinder and valve construction.

Offline Charles Lamont

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Re: Trevithick
« Reply #16 on: August 27, 2020, 08:41:55 PM »
Brian, as I made this steam distribution valve for the full size replica of Trevithick's Catch Me Who Can locomotive, I can explain it. First, to save me a bit of time, please check out this:
https://en.wikipedia.org/wiki/Four-way_valve
Also, please check your messages in this forum.
Charles

Offline Brian Rupnow

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Re: Trevithick
« Reply #17 on: August 27, 2020, 09:20:44 PM »
Charles--i have checked my messages. There is nothing new there.---Brian

Offline JULIUS

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Re: Trevithick
« Reply #18 on: August 27, 2020, 10:23:54 PM »
Brian

The 10.25" model drawings are attached.

Offline JULIUS

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Re: Trevithick
« Reply #19 on: August 27, 2020, 10:25:08 PM »
second lot

Offline Charles Lamont

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Re: Trevithick
« Reply #20 on: August 27, 2020, 10:33:51 PM »
Brian, sorry, I think it must have been an email.

Offline JULIUS

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Re: Trevithick
« Reply #21 on: August 27, 2020, 10:42:25 PM »
Brian

Here are the drawings of the 5" loco

Julius

Offline Brian Rupnow

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Re: Trevithick
« Reply #22 on: August 27, 2020, 10:57:21 PM »
Just as I was reaching a point where I didn't want to go any farther without more knowledge about the cylinder and valve, Julius from New Zealand has came thru with a bunch of drawings and saved me. Thank you Julius, from the far side of the world!!!


Offline crueby

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Re: Trevithick
« Reply #23 on: August 27, 2020, 11:03:52 PM »
Looks to be a fun project, watching along with great interest.    :popcorn: :popcorn: :popcorn:

And thanks from me to Julius, I have picked up a lot from your past plan postings too!   :ThumbsUp:

Offline Charles Lamont

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Re: Trevithick
« Reply #24 on: August 27, 2020, 11:12:59 PM »
The arrangement shown in Julius's drawings is ingenious, but totally unlike anything Trevithick actually used.

These videos may help with an understanding of how the valve is tripped by tappets at each end of the stroke:
« Last Edit: August 27, 2020, 11:32:10 PM by Charles Lamont »

Offline Brian Rupnow

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Re: Trevithick
« Reply #25 on: August 28, 2020, 01:12:28 AM »
Charles--Have a look at the video in post #9. The animation in that link is exactly the same as what Julius posted.---Wait a minute--The man who made that video and animation refers to the drawings created by Julius. I like Julius' version better, but I wonder if anyone has actually built it and had it in service?
« Last Edit: August 28, 2020, 01:20:25 AM by Brian Rupnow »

Offline Jasonb

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Re: Trevithick
« Reply #26 on: August 28, 2020, 07:38:35 AM »
Just as I was reaching a point where I didn't want to go any farther without more knowledge about the cylinder and valve, Julius from New Zealand has came thru with a bunch of drawings and saved me. Thank you Julius, from the far side of the world!!!


He offered them to you several days ago and that was the offer I said to take up. Not just the drawings but the CAD files as well

Do bear in mind that Julius generally has a "for personal use only" note with his drawings so a bit bad form to start charging for drawings that may not have been possible without his.

Offline Charles Lamont

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Re: Trevithick
« Reply #27 on: August 28, 2020, 08:36:28 AM »
I have seen in the flesh finished examples of this model, which is based on the surviving original engine in The Science Museum (London).  The model has the correct type of rotary 4-way valve.

The video in post no 9 is particularly unfortunate, as it goes to great lengths to promulgate a completely false idea of how Trevithick's engines worked, based on Julius's invention of a shuttle valve.

http://www.brunell.com/product.asp?cookiecheck=yes&P_ID=135&numLanguageID=1

Offline Mcgyver

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Re: Trevithick
« Reply #28 on: August 28, 2020, 12:53:28 PM »
People like Julius who freely contribute so many great drawings do a great service to the hobby - THANK YOU!

It risk of looking like the ungrateful lout inspecting the gift horse's teeth, I like to table a thought from the peanut gallery.

It would be really helpful these drawings included some comments on their origin or pedigree.  A small engine can be a makers interpretation, freelance or at the other end of the spectrum a rivet counted model of a prototype.  All are good, however including a bit of info around this would be so very helpful to those of looking at the drawings as potential builds.

This is particular frustrating with grabcad - so much content but you just have zero idea of where the author is coming from.   It could be anything from an artistic interpretation that would never work to an exact reproduction of from a 100 year ME issue or done from first hand measurements by the author, and so on.  Not knowing seriously degrades the usefulness of the drawings/models that a lot of time was put into;  what could be a 10/10 becomes a 2.

If people did this, the person on grabcad would have given credit to Julius and say whether he'd mod'd it or reproduced it exactly etc...it would create a chain would enhance things imo

Just a thought - and thanks again Julius for all you contribute

Mike
« Last Edit: August 28, 2020, 12:59:28 PM by Mcgyver »

Offline crueby

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Re: Trevithick
« Reply #29 on: August 28, 2020, 01:44:13 PM »
I have seen in the flesh finished examples of this model, which is based on the surviving original engine in The Science Museum (London).  The model has the correct type of rotary 4-way valve.

The video in post no 9 is particularly unfortunate, as it goes to great lengths to promulgate a completely false idea of how Trevithick's engines worked, based on Julius's invention of a shuttle valve.

http://www.brunell.com/product.asp?cookiecheck=yes&P_ID=135&numLanguageID=1
Charles, do you have any information/links on how the piston valves worked on the Trevithick loco? The videos you posted dont show any detail, though you can hear the valve actuating in a way consistant with what Julius drew. You say his layout is not right, but what IS the right way?Thanks!