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From: hc1@reef.cis.ufl.edu (Harry Campbell)
Newsgroups: sci.military
Subject: MBT-70
Message-ID: <1991Jun14.075939.19915@amd.com>
Date: 14 Jun 91 00:55:56 GMT
Sender: military@amd.com
Organization: U of Florida. Computer Science Dept.
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Approved: military@amd.com


From: hc1@reef.cis.ufl.edu (Harry Campbell)


This is in response to the article about the MBT-70.

     The project was cancelled mainly because of the gun system.  We
Americans wanted our home-grown 152mm gun/launcher, while the German's
insisted on their 120mm Rhienmetal gun.

     The 152mm gun/launcher was already being used on the M60A2 and the
M551 Sheridan light tank (used by the 82nd Airbourne in Desert Strom,
and Panama).  When the M551 saw combat in Vietnam, the crews found that
the severe recoil from firing the gun would damage the fire-control for
the Shillelagh missile.  In Panama the M551 served well as assault guns
('bunker busting'), but to my knowlege the Shillelagh were not fired.
The M60A2 with heavier steel armor plate (not the aluminum/styrofoam
"armor" on the M551), overcame the recoil problem providing a sturdier
firing base.  But soon enough the Russians would see how well Reactive
Armor worked for the Isrealis, and start puting it on their production
MBT's.  The Shillelagh is known to penetrate about 600mm of armor
plate, and it would be hard pressed T-70B with R. A. (let alone a
T-80).  The 152mm round is a HEAT warhead that penetrates about 450mm,
making it virtually useless against the frontal armor of most MBT's.

     So it was finally shown that the 152mm gun was not the
super-weapon it was once thought to be.  The Army has completely
abandoned the M60A2, and the 82nd Airbourne is the only U.S. force to
use the Sheridan in the front-line (due to it's airportability).

     The U. S. came to the conclusion that the new tank must be armed
with a standard gun, with some sort of AP-DS round (Meanwhile the
German's are saying, "I told you so").  Of the guns considered the two
finallists were the Rhinemetal 120mm smoothbore, and the U. S. made
105mm M68A1 rifled gun (the same gun used on the M60A3).  The design
for the 105mm gun came from the Brittish L7 gun, and though the
Brittish had abandoned it for their own 120mm rifled cannon on the
Chieftain, it was (and is) in use by many armies in NATO.  Of course we
chose the 105mm gun, despite it's being clrearly outmatched by the
German gun.  And though no-one would admit it at the time the only real
reason, besides standardization of ammo, was the fact that we would
have to lisence the gun from Germany, instead of having the money stay
here in the U. S.

     The two sides began to have a serious falling out, and when the
Pentagon started changing the design requirements (insisting on a tank
with a 4-man crew), the project was killed.

     The MBT-70 was replaced with the XM-1, which was to have the 105mm
cannon, and a crew of four, much of the suspension, and fire-control
ideas of the MBT-70 were retained.  After a few years of production it
was decided that the 105mm gun might prove inadequate against the
newest generation of soviet tanks.  The upgrade for the Abrahms
M1-Improved turned out to be a 120mm Smoothbore produced on a foreign
liscense (guess who!).

     To be honest, it is likely that we came out with a far suppior
tank, by incorporating the new Chobahm armor, Thermal Imaging, and
highly improved engine that were all developed after the MBT-70 was
scrapped.  The MBT-70 would already be obsolete.