I guess soon I'll be called the radiator/fan guy because that's all I seem to question on this forum :) In the late 50's-early 60's, EMDs (GP7 GP9) used multiple external top fans and GE used multiple internal fans. How did the single fan in the RS-11 perform the 3 functions of: a) radiator cooling, b) intake manifold air source, and c) dynamic braking grid cooling? It WAS a large diameter fan in the LHF top, and the RS-11 was a 12 Cyl./4 stroke diesel, but I can't understand how one fan took care of everything when the other major manufacturers needed multiple fans ??? Thanks.
VGN Jess I guess soon I'll be called the radiator/fan guy because that's all I seem to question on this forum :) In the late 50's-early 60's, EMDs (GP7 GP9) used multiple external top fans and GE used multiple internal fans. How did the single fan in the RS-11 perform the 3 functions of: a) radiator cooling, b) intake manifold air source, and c) dynamic braking grid cooling? It WAS a large diameter fan in the LHF top, and the RS-11 was a 12 Cyl./4 stroke diesel, but I can't understand how one fan took care of everything when the other major manufacturers needed multiple fans ??? Thanks.
That's easy - it didn't....
The RS-11 fan cooled the radiator only.
Locomotives with dynamic brakes had a "bathtub" arrangement above the engine where air was drawn in through openings in the upper hood side and internal electric fans in series with the resistances blew the air through the resistors and out through vents in the hood roof.
I don't think the RS-11 had any fans on the intake side, but some Century series took air from the traction motor blower driven mechanically by the diesel engine.
M636C
Thanks for the response; appreciate it. Why did the EMD GP7 (1500 HP) need so many fans and the RS-11 (1800 HP) get by with only one? Was it because the EMD had to cool 16 cyls. and the ALCO only 12?
The following shows the workings of an RS11.
http://www.rr-fallenflags.org/manual/rs11-op.pdf
One BIG fan would cool as much as three or four smaller ones, the latter turning off/on in sequence as required.
The RS-11 fan was mechanical thru a 90 degree gear box and magnetic clutch.
Geep fans were electric. Often one could be shut down for winter and it's opening covered on top of hood. Later GEEPS received big fans
Thank You.
NDG: Thanks for both the informative response and the PDF link. That answered all my questions.
A Geep with BIG fans.
http://cprdieselroster.com/Roster%20Archive/CP%208800A/CP%208825-3.jpg
Thank You
So this threads wasn't started by someone who really likes RS-11's....
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