Re: Three cylinders at 120 degrees for even pull
| March 09, 2017 06:09PM |
|
Earl Wrote:
-------------------------------------------------------
> I believe you are incorrect. A 3-cylinder simple
> locomotive (like a UP 9000 or an SP 5000) have
> cranks 120 degrees apart. If I knew how to attach
> it I have a good recording of a 9000 starting a
> heavy train. All the exhausts are the same
> distance apart. When it starts to get a roll and
> hooked up it starts to go goofy.
That's what I thought as well - otherwise you'd have an uneven power curve, and a definite surge at the drawbar. Imagine what the slam of a three-cylinder K-45 would have done to those wooden boxcars with cranks at other than 120° apart . . .
> The problem with the Gresley motion was that it
> worked off the valve stems of the outside cylinders.
> So, any lost motion in the regular Walschearts gear
> got transmitted to the Gresley gear, which had its
> own bunch of bushings that got worn out pretty quick.
> The end result was the center cylinder usually had
> some pretty wacked out valve events.
. . . especially in the later years as maintenance was cut back (and as noted above - see [ngdiscussion.net]).
- El Abuelo Histœrico, Greengo y Curmudgeoño de los Locomoturas Viejos y Verdes,
aka Der Grossväterlich DünkelOlivGrünDampfKesselMantelLiebHabender
-------------------------------------------------------
> I believe you are incorrect. A 3-cylinder simple
> locomotive (like a UP 9000 or an SP 5000) have
> cranks 120 degrees apart. If I knew how to attach
> it I have a good recording of a 9000 starting a
> heavy train. All the exhausts are the same
> distance apart. When it starts to get a roll and
> hooked up it starts to go goofy.
That's what I thought as well - otherwise you'd have an uneven power curve, and a definite surge at the drawbar. Imagine what the slam of a three-cylinder K-45 would have done to those wooden boxcars with cranks at other than 120° apart . . .
> The problem with the Gresley motion was that it
> worked off the valve stems of the outside cylinders.
> So, any lost motion in the regular Walschearts gear
> got transmitted to the Gresley gear, which had its
> own bunch of bushings that got worn out pretty quick.
> The end result was the center cylinder usually had
> some pretty wacked out valve events.
. . . especially in the later years as maintenance was cut back (and as noted above - see [ngdiscussion.net]).
- El Abuelo Histœrico, Greengo y Curmudgeoño de los Locomoturas Viejos y Verdes,
aka Der Grossväterlich DünkelOlivGrünDampfKesselMantelLiebHabender
Sorry, only registered users may post in this forum.
488 stops for water at Los Pinos tank on closing day Oct. 1979. Photo courtesy Don Richter
The NGDF was started by Don Richter and is currently operated in his memory by Nathan Holmes and others. Others who have contributed to the upkeep of this board are (in no particular order): Charles McCandless, Everett Lueck, Ted Wilton, Cole Adams, James Bane, John Moellmer, Jon Bentz, Linn Moedinger, lloyd lehrer, Rod Jensen, John Craft, Steven Forney, Herb Kelsey, Bill Ramaley, Russ Sperry (El Russo Loco), Josh McNeal, John West, Jim Armstrong, Bob Bergstrom, Greg Scholl, Blake Forbes Doug van Veelen and Mark Fuller.