Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!att!cbnews!military
From: kluksdah@enuxha.eas.asu.edu (Norman C. Kluksdahl)
Newsgroups: sci.military
Subject: Re: MBT Tank running gear
Summary: new differentials
Message-ID: <7515@cbnews.ATT.COM>
Date: 16 Jun 89 03:34:11 GMT
References: <7406@cbnews.ATT.COM> <7457@cbnews.ATT.COM>
Sender: military@cbnews.ATT.COM
Organization: Arizona State Univ, Tempe
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Approved: military@att.att.com



From: kluksdah@enuxha.eas.asu.edu (Norman C. Kluksdahl)
In article <7457@cbnews.ATT.COM>, welty@lewis.crd.ge.com (richard welty) writes:
> 
> =power train's efficiency, too.
> 
> there shouldn't be much effiency loss due to the
> presence of a drive shaft; more will be lost in the differential if
> the engine is longitudinal instead of transverse.
> 
One of the main situations in which power loss becomes critical is in
turning a tracked vehicle.  A conventional differential arrangement
consumes power while trying to turn the tracks at different rates, or
in different directions.

Recently, there was an article in Popular Science about a differential
which the USMC was apparently going to use in an AFV--the Gleason
differential.  This mechanism operates unlike a conventional differential.
If I recall correctly, this differential is currently in use in all airports,
in the tractors used to push aircraft around.  If one wheel is on ice and
one on dry pavement, a conventional differential will put all power into the
wheel on ice, and the machine sits.  The Gleason differential puts power into
the stationary wheel.  No spins.

The version used in a tracked vehicle is modified.  Two such differentials,
with a reversing gear between the outputs on one side, are coupled.  Turning
is accomplished by spinning part of the assembly with an auxiliary electric
motor, which changes the speed of one track or the other.  The data in favor
of this differential is impressive.  On an AFV (I don't remember the type),
the conventional differential steering could spin the vehicle (within its
own length) about 3/4 of a revolution from a standing start, before the
engine stalled.  With the new differential steering mechanism, the number of
revolutions before engine stall was about 2 1/2.  Less power loss in a turn,
more maneuverability, more survivability.  

Does anyone know if this is now in current use anywhere?  
(If anyone has better knowledge, or the article, please feel free to
correct any errors.  The above was quoted from a memory unit not equipped
with error detection/correction :-) )

**********************************************************************
Norman Kluksdahl              Arizona State University
            ..ncar!noao!asuvax!enuxha!kluksdah
alternate:   kluksdah@enuxc1.eas.asu.edu

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