Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!att!cbnews!military
From: welty@lewis.crd.ge.com (richard welty)
Newsgroups: sci.military
Subject: Re: MBT Tank Turrets - (question)
Message-ID: <7457@cbnews.ATT.COM>
Date: 14 Jun 89 03:27:03 GMT
References: <7406@cbnews.ATT.COM>
Sender: military@cbnews.ATT.COM
Organization: New York State Institute for Sebastian Cabot Studies
Lines: 48
Approved: military@att.att.com



From: welty@lewis.crd.ge.com (richard welty)

In article <7406@cbnews.ATT.COM>, Bill Thacker writes: 
=cindi%bucsb.BU.EDU@bu-it.bu.edu (Cynthia Fong) writes:
=>    a) Reduced tank gun depression.

=And this is important; depression is critical for obtaining hull
=defilade positions behind hill crestlines.

indeed.  this is one of the reasons why US tank designs have tended
to be taller than Soviet designs since WWII (another reason is that
US tank designers take crew comfort more seriously than Soviet
designers.)

=>    b) Maintenance difficulties realting to access to the power-pack, but
=>       this shouldn't be much of a big problem; the Merkava doesn't have
=>       a bad maintenance rep does it?

=I would think that a good engine design would minimize the difficulties;
=but you'd still have problems with routine maintenance; lubrication and the
=like.  With the large road wheels in current vogue, it'd be tough even
=if you provided side access panels; and the presence of these would weaken
=the side armor.

there is a major advantage to providing a large hatch over the engine
compartment (large enough to pull the engine as a complete unit);
it allows you to do a complete swap quickly when you are in a hurry
(e.g. you need to get units back into combat as soon as possible.)
at least some of the T-series Soviet tanks require disassembly of the
engine inside the compartment piece-by-piece to make repairs.

=2) The transmission and differential have to be either at the front or
=rear, wherever you locate the drive sprockets.  It probably improves space
=utilization to site the engine at the same place; maybe increases the
=power train's efficiency, too.

this is sort of tricky.  if the engine and transmission are at opposite
ends, then you have to provide a driveshaft; a potentially messy problem
in a tank design.  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.

richard
-- 
richard welty         welty@lewis.crd.ge.com         welty@algol.crd.ge.com
           518-387-6346, GE R&D, K1-5C39, Niskayuna, New York