kluksdah@enuxha.eas.asu.edu (Norman C. Kluksdahl) (06/16/89)
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 standard disclaimer implied