1 Steam Cars : Phorum
General Steam Car topics
Joy Valve Gear
Posted by: Garry Hunsaker (IP Logged)
Date: April 15, 2002 10:48PM
<HTML>No, I ain’t planning on using the Joy valve gear. It’s just one of those things I keep seeing in texts that never explain the geometry, or how to do lay out, of this system. Does anyone know of a ‘good’ source of data on the Joy gear?
Garry... Cursed of trying to understand every mechanical thing I run into.</HTML>
Garry... Cursed of trying to understand every mechanical thing I run into.</HTML>
Re: Joy Valve Gear
Posted by: Peter Heid (IP Logged)
Date: April 16, 2002 10:17PM
<HTML>Garry,
I have Peter Brow to thank for this answer. On his recomendation I purchased the book "Self-Propelled Vehicles", by James E. Homans (New York: Theo. Audel & Company, 1910). There are 2 very good diagrams of the joy linkage, one from the White steamer. They are a good clear view, some of the best I have seen. It is a good book to have on the shelf.
Peter Heid</HTML>
I have Peter Brow to thank for this answer. On his recomendation I purchased the book "Self-Propelled Vehicles", by James E. Homans (New York: Theo. Audel & Company, 1910). There are 2 very good diagrams of the joy linkage, one from the White steamer. They are a good clear view, some of the best I have seen. It is a good book to have on the shelf.
Peter Heid</HTML>
Re: Joy Valve Gear
Posted by: Peter Brow (IP Logged)
Date: April 17, 2002 05:23AM
<HTML>Hi Pete,
As the automatic doors in "Hitchhiker's Guide to the Galaxy" say, "glad to be of service".
The two cuts of the White valve gear in Homans are also included, in clearer form, in the booklet "White Steam Cars -- Models M & O -- Instructions" (1909), available in excellent reprint form from the SACA Storeroom (I think). Don't know the SACA stock number.
Glad you could find a copy of Homans; mine is starting to come apart at the seams. The test tables on the White steamer, from Prof. Carpenter's famous tests, are particularly interesting.
I think you could scale the drawings/photos and build a working valve gear from the above sources. One downside of Joy gear is that the lead/compression does not increase at shorter cutoff as in Stephenson gear. This is mentioned on page 115 of Clymer -- one of those comments whose brevity is way out of proportion to its importance. What Clymer doesn't quite connect the dots on is that with Joy gear, the bearings &c are not cushioned on deceleration at short cutoff/hi speed, putting more loads and wear on them.
Which brings to mind the strongly-emphasized warnings in White literature about not racing the declutched engine during warmup (I suspect that water slugs are only part of the reason).
The upside of Joy gear, besides eliminating pesky crankshaft-lengthening eccentrics, is that you can shorten the admission at lower car/engine speeds with less jerkiness. But then you discover the wisdom of the old locomotive engineers' saying that "expansive working is expensive working" (true at low loads/rpms). Despite their considerable superiority in engineering sophistication and theoretical and test-bench efficiency, White steam cars reportedly get about the same fuel mileage as Stanleys under road conditions. Stephenson gear also has a long-standing reputation for being more rugged than Joy.
As Ren & Stimpy say, Oh, Joy!
Peter</HTML>
As the automatic doors in "Hitchhiker's Guide to the Galaxy" say, "glad to be of service".
The two cuts of the White valve gear in Homans are also included, in clearer form, in the booklet "White Steam Cars -- Models M & O -- Instructions" (1909), available in excellent reprint form from the SACA Storeroom (I think). Don't know the SACA stock number.
Glad you could find a copy of Homans; mine is starting to come apart at the seams. The test tables on the White steamer, from Prof. Carpenter's famous tests, are particularly interesting.
I think you could scale the drawings/photos and build a working valve gear from the above sources. One downside of Joy gear is that the lead/compression does not increase at shorter cutoff as in Stephenson gear. This is mentioned on page 115 of Clymer -- one of those comments whose brevity is way out of proportion to its importance. What Clymer doesn't quite connect the dots on is that with Joy gear, the bearings &c are not cushioned on deceleration at short cutoff/hi speed, putting more loads and wear on them.
Which brings to mind the strongly-emphasized warnings in White literature about not racing the declutched engine during warmup (I suspect that water slugs are only part of the reason).
The upside of Joy gear, besides eliminating pesky crankshaft-lengthening eccentrics, is that you can shorten the admission at lower car/engine speeds with less jerkiness. But then you discover the wisdom of the old locomotive engineers' saying that "expansive working is expensive working" (true at low loads/rpms). Despite their considerable superiority in engineering sophistication and theoretical and test-bench efficiency, White steam cars reportedly get about the same fuel mileage as Stanleys under road conditions. Stephenson gear also has a long-standing reputation for being more rugged than Joy.
As Ren & Stimpy say, Oh, Joy!
Peter</HTML>
Re: Joy Valve Gear -- erratum
Posted by: Peter Brow (IP Logged)
Date: April 18, 2002 06:52AM
<HTML>In previous post I wrote:
"What Clymer doesn't quite connect the dots on is that with Joy gear, the bearings &c are not cushioned on deceleration at short cutoff/hi speed, putting more loads and wear on them."
But should have written:
"What Clymer doesn't quite connect the dots on is that with Joy gear, the bearings &c are not AS cushioned DURING PISTON/CONROD deceleration at short cutoff/hi speed, putting more loads and wear on them."
Otherwise, it sounds like a reference to engine or vehicle deceleration, rather than cyclic deceleration of reciprocating parts past mid-piston-strokes, which is the intended meaning. Cushioning the piston/conrod with some lead/compression at higher rpms cuts wear on the bearings and extends engine life. Plus the lead (pron. "leed", ie inlet opening before TDC) helps with engine breathing & thus increases max rpm without more port area/clearance volume, and so on into the design tradeoff game.
I explain this because a reader once asked me how it could possibly be useful to inject a heavy metal like "lead" into steam engine cylinders at higher rpms. He thought that only old gas engines needed "lead". Ah, the joys of unphonetic spelling.
Peter</HTML>
"What Clymer doesn't quite connect the dots on is that with Joy gear, the bearings &c are not cushioned on deceleration at short cutoff/hi speed, putting more loads and wear on them."
But should have written:
"What Clymer doesn't quite connect the dots on is that with Joy gear, the bearings &c are not AS cushioned DURING PISTON/CONROD deceleration at short cutoff/hi speed, putting more loads and wear on them."
Otherwise, it sounds like a reference to engine or vehicle deceleration, rather than cyclic deceleration of reciprocating parts past mid-piston-strokes, which is the intended meaning. Cushioning the piston/conrod with some lead/compression at higher rpms cuts wear on the bearings and extends engine life. Plus the lead (pron. "leed", ie inlet opening before TDC) helps with engine breathing & thus increases max rpm without more port area/clearance volume, and so on into the design tradeoff game.
I explain this because a reader once asked me how it could possibly be useful to inject a heavy metal like "lead" into steam engine cylinders at higher rpms. He thought that only old gas engines needed "lead". Ah, the joys of unphonetic spelling.
Peter</HTML>
Re: Joy Valve Gear
Posted by: David K. Nergaard (IP Logged)
Date: April 18, 2002 11:43AM
<HTML>I was recently given a book which contains rules for laying out the Joy gear: "Steam Engines and Valve Gears" , International Textbook Company, Scranton, Penna., 1929. I will copy the appropriate pages if you wish.</HTML>
Re: Joy Valve Gear
Posted by: ronald parola (IP Logged)
Date: April 22, 2002 11:35PM
<HTML>There are great animations of various valve gears on the web at; small scale live steam. they are downloadable dos programs with areas that you can set sizes of parts so you can tailor whichever train to your specs, AND they make great screen savers. If you can't find them I can get the proper address, or if you wish, copy mine and either email them or stuff them on 2 floppies Cheers Ron P</HTML>
Re: Joy Valve Gear
Posted by: G. B. Gilbert (IP Logged)
Date: April 23, 2002 02:46AM
<HTML>The valve gear program which Ron recommended is here
[www.tcsn.net]
i've only used the dos version, i highly recommend it. The enclosed file 'instruct.txt' has a list of reference texts.
There is a windows version of the program as well.</HTML>
[www.tcsn.net]
i've only used the dos version, i highly recommend it. The enclosed file 'instruct.txt' has a list of reference texts.
There is a windows version of the program as well.</HTML>
Re: Joy Valve Gear
Posted by: Garry Hunsaker (IP Logged)
Date: April 24, 2002 12:29AM
<HTML>Thanks guys
Looks like I'll have to update this old Macintosh so I can run 'Virtual PC'
Garry</HTML>
Looks like I'll have to update this old Macintosh so I can run 'Virtual PC'
Garry</HTML>
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