York engine cad model & question

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Anne from Little Britan
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York engine cad model & question

Post by csonics » Wed Nov 18, 2009 5:53 pm

Posted on behalf of marinesteam:


marinesteam
Lighting the Boiler


Joined: 28 Nov 2007
Posts: 39
Location: Colorado, USA
Posted: Mon Feb 16, 2009 10:26 pm Post subject: York engine cad model & question
This may be a silly question to some but since I am in a dry area as far as steam boats go I don't have much up close and personal experience.


This first jpeg is a view of the rear of the engine facing forward.

Image

When the reverser lever (not shown yet) is pulled toward the starboard side the link will be in the position as show. In the prints this appears to be the forward gear. Is this the standard operating positon of the reverser for forward?

This second jpeg is an overall view of the model so far, just for looking at.

Image

hanks

Ken
Colorado, USA
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steamboatjack
Urchin


Joined: 01 Oct 2007
Posts: 39

Posted: Tue Feb 17, 2009 1:20 pm Post subject: york engine
Ken,
I have not built a york, but looking at the photo on Elliott Bay's site the wayshaft is shown on the front side of the engine (i.e. the turned column side) your drawing shows it on the rear (crosshead side)?

anyway, assuming you are building a right hand rotation engine (clockwise in your drawing) as the L.P. cylinder is a slide valve the eccentric will be 90 degrees plus the angle of advance AHEAD OF THE CRANK. With the crank drawn at B.D.C. the ahead eccentric should therefore be about between 10 & 11 o,clock.(the angle of advance is usually around the 30-35degree mark).

With the launch type links suspended at one end (not the best idea) the ahead eccentric should be nearest the suspension point of the draglink, however this depends if you want "open" or "crossed" rods.
I always prefer "open" rods as the lead is less at full gear but to have this, the wayshaft has to be on the front of the engine. To build as per your drawing you would have "crossed" rods.
I much prefer the double bar type links as used on the E.B. triple. As these have central suspension the wayshaft can be on either side, trouble is they need more room axially along the engine axis.

I could give more detail but I expect folks are asleep already.
Oh I see the H.P. is a piston valve, assuming this is "inside admission" then the eccentric positions will be different to the L.P.
regards steamboatjack.
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marinesteam
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Joined: 28 Nov 2007
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Location: Colorado, USA
Posted: Tue Feb 17, 2009 2:16 pm Post subject:
Steamboatjack,

Thanks for the thoughtfull reply.

The prints for the York indicate a change in the position of the wayshaft from the front to the back of the engine due to a redesign of the quadrant and lever assembly. The print for the drag link has a note: "Length different if gear mounted on back of engine". This is why I was double checking by building the CAD model before cutting chips.

It appears from your description that I have the eccentrics reversed. It also looks like I need to better understand the eccentric diagrams in the plans. The odd part is the LP diagram says "viewed from rear in ahead gear" and the HP diagram says "viewed from front" but the link is draw to the right of the centerline in both diagrams. I assumed that both would be shown in ahead gear but if this were the case the link would need to be on the opposite side of center due to the change in orientation of the view. Am I missing something? I'll send a scan later.

I'll work on the model tonight and have another go at it.

Thanks

Ken
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marinesteam
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Joined: 28 Nov 2007
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Location: Colorado, USA
Posted: Tue Feb 17, 2009 10:27 pm Post subject:
Here are the eccentric diagrams I spoke of earlier....

Image

steamboatjack
Urchin


Joined: 01 Oct 2007
Posts: 39

Posted: Wed Feb 18, 2009 3:19 am Post subject:
Ken,
study of the scanned drg. the drg bottom right "viewed from front" taking this as correct, it has the eccentrics in the correct positions but the link sloping the wrong way as you suggested and it is connected "crossed" rods.
a lot of drawings have similar errors.
in this drg. being an inside admission valve the eccentric trails the crank 90 deg. (LESS angle of anvance).

As the L.P. is shown as "open"rods in the upper sketch, you have a problem.
As mentioned before, with this link and the wayshaft at the rear you can only us"crossed" rods to keep the ahead eccentric next to the draglink pivot. it would work as open rods but the "die slip" may be excessive?
I would guess someone has changed the position of the wayshaft without thinking the thing through. I would put it at the front if you can, the lever and quandrant can be arranged many ways its not important so long as it provides the movement required.
n.b. "open rods" appear open when the crank is at B.D.C. (outside admission) and at T.D.C. (inside admission).
hope this helps
jack
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marinesteam
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Joined: 28 Nov 2007
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Location: Colorado, USA
Posted: Wed Feb 18, 2009 1:35 pm Post subject:
Thanks,

That really does help a lot.

The drawings for the original quadrant are still in the print package. The original quadrant and reverse lever were castings and may have been changed to reduce cost. The lever was also moved from the center of the wayshaft to the end. There may have been an interference between the reverse lever and the receiver as well. I was thinking about re-designing the reverse lever from square stock to a built-up, turned part anyway and it would be easy to include the quadrant re-design at this time.

The nice thing with the CAD model is that I can quickly check the amount of die slip in both configurations now that I have the eccentrics worked out. I may move the wayshaft back to the front if the slip is excessive at the rear.

I am hoping to get some time in the garage si I can actually make some chips, so it may be a few days before I get back to the CAD model. I'll post when I have had a chance to take a closer look, or if I have some actual real parts to show.

Thanks again

Ken
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preaton
Just Starting Out


Joined: 19 Dec 2007
Posts: 10
Location: Auckland, New Zealand
Posted: Sat Feb 21, 2009 1:05 am Post subject:
Ken, I agree the plans are difficult to fathom on this point. What you have drawn is correct. That's how my engine looks at the LP end. I have seen some examples of this engine built with the layshaft (not the right term) mounted on the receiver side of the engine. I prefer it the way you have drawn it.
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steamboatjack
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Joined: 01 Oct 2007
Posts: 39

Posted: Sun Feb 22, 2009 5:58 am Post subject:
Its called many names weightshaft on british locos, wyper shaft in many marine textbooks, I use wayshaft because most old books on marine steam engines use the term "headway & "sternway" to denote the engine rotation. the side fitted should not be a question of choice but of sensible design?
regards jack
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87gn@tahoe
Full Ahead


Joined: 23 Feb 2009
Posts: 148
Location: South Lake Tahoe, CA
Posted: Thu Feb 26, 2009 10:08 pm Post subject:
Hello all, this is my first post.

Ken, I am going to send you a PM with information for contacting the ultimate authority on this particular engine. He is the one who originally designed and built it.

I am sure he will be willing to help you with any question you may need answered.

Wes
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Wesley Harcourt
-S.L. Wayward Belle (Mr. Grosjean was/is a genius.)
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preaton
Just Starting Out


Joined: 19 Dec 2007
Posts: 10
Location: Auckland, New Zealand
Posted: Fri Feb 27, 2009 3:41 am Post subject:
John York was very happy to answer all my questions. Give him my regards. His engine is a beauty.

Cheers

Paul
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marinesteam
Lighting the Boiler


Joined: 28 Nov 2007
Posts: 39
Location: Colorado, USA
Posted: Sat Feb 28, 2009 12:02 am Post subject:
Hello all,

Paul & Wes, Thanks!

Here is an animation of the not nearly complete CAD model.

http://www.youtube.com/watch?v=R0YFwrQH58A

More later

Ken
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87gn@tahoe
Full Ahead


Joined: 23 Feb 2009
Posts: 148
Location: South Lake Tahoe, CA
Posted: Sat Feb 28, 2009 11:34 pm Post subject:
Ken,

Looks GREAT... you seem to be a master of CAD drawing...

Do you have CNC equipment also?

The York enigines are BEAUTIFUL when completed.. I especially like the long-legged aspect for some reason.. girls and steam engines have to have long legs for me.

I don't know if it is coincidence or not, but all of the York's I have run and seen in person have the same base colour as your CAD drawing, and IMO, it is the best colour for that enigine.

wes
_________________
Wesley Harcourt
-S.L. Wayward Belle (Mr. Grosjean was/is a genius.)
-S.L. George H. Sandin (Father's boat. Cut my teeth on that one.)
-'64 Buick Riviera
-'65 Buick Special WAGON
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87gn@tahoe
Full Ahead


Joined: 23 Feb 2009
Posts: 148
Location: South Lake Tahoe, CA
Posted: Sun Mar 22, 2009 1:14 pm Post subject:
Ken,

Was John able to help you out?

Any more updates?
_________________
Wesley Harcourt
-S.L. Wayward Belle (Mr. Grosjean was/is a genius.)
-S.L. George H. Sandin (Father's boat. Cut my teeth on that one.)
-'64 Buick Riviera
-'65 Buick Special WAGON
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