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US Army XM1 MBT Comp

Pioneer

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I am looking for the competing design of General Motors Corporation that ran against, and lost to the Chrysler Corporation's Main Battle Tank design of 1973, that would become the now famous 'M1 Abrams MBT'
Pictures, drawings and technical data please if you have it


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smurf

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Hunnicutt has it, but mine is still packed after a move. If no one else supplies after a day or two, I'll try to find it.
 

JAZZ

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GMotors MBT
 

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JonCatalan

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AFAIK, the GM version had a conventional diesel engine, as opposed to Chrystler's gas-turbine, and both adopted British chobham.
 

smurf

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I have tried to post some info from Hunnicutt 'Abrams' but keep getting 'Internal server error'
I am having problems with coontinual interrupted connection to internet. Can anyone advise, please?
 

smurf

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Abrams

This is really the XM1 thread, where I can't post pictures
 

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overscan (PaulMM)

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http://www.ndu.edu/ctnsp/Def_Tech/DTP22%20Critical%20Technology%20Developments%20Abrams%20Tank.pdf
 

Pyrrhic victory

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http://findarticles.com/p/articles/mi_m1316/is_v19/ai_4696991/pg_1

Here's a 1987 article from the Washington Monthly entitled "The first Chrysler bail-out; the M1 tank". It discusses the financial troubles of Chrysler in the 1970s and desperately needed this contract, while GM was decent financial shape. The Army was set to pick the GM XM1 in 1976 but SecDef Rumsfeld refused to rubber stamp it, and changed the requirement to include the 120mm and turbine engine. Along with intense lobbying, this helped Chrysler secure the contract.

As this article was written before the first Persian Gulf war, the popular perception of the Abrams in the press was still that of an Edsel with a helicopter engine in it instead of the God on tracks we've been hearing about for the last 15 or so years.
 

Pioneer

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Thanks for this important article and the previous attached pic

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Anderman

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Strange article, the autor should asked himself why germany developed a 120 mm gun for the mbt 70 if the 105 mm was good enough.
And if the 105 mm gun was god enough why replace all the tanks which had them ?
 

Przezdzieblo

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I cannot stand for the author of that article (interesting and nice find - many thanks!), but 105 mm was considered both proven and with enough punch. In `70s USA just developed new generation of APFSDS ammunition (with DU monobloc penetrator), and had a hope of "new life" of 105 mm gun. Also, there were a ideas (that changed to plans in early `80s) of using 105 mm gun with longer barrel (L/65 instead of L/51). Since circa 1975 German 120 mm gun still was only experiment, and own US experience with smoothboore and APFSDS were not very encouraging to swap to 120 mm. Also, cannot forget about other reasons - national and technical pride, economical issues (need of new licence and ammunition production - and what to do with tons of 105 mm ammo?).
Note in race to arm XM1 there was also British competitor, with their 110 mm and later 120 mm rifled guns.
 

Anderman

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IIRC the 120 mm smoothbore was the german weapon of choice during the MBT/KPZ 70 project, so it looks this kind of gun was around a long time.
 

Przezdzieblo

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Me wrong - 120 mm gun not "experiment", rather "in development stage". German worked with that gun since circa 1965, but it was not ready enough before mid 1970s. It is hard to tell if it was weapon of choice for KPz 70 (and US MBT70) - during development no prototype of that tank was armed with 120 mm smoothbore. Kpz 70 (US-FRG) was dropped for new tank (still called KPz 70 - MBT for 70s) with 105 or 120 mm smoothbore gun (but 152 mm with Shillelagh system still was considered for some time).
 

Rickshaw

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Increasing the length of the 105mm to L/65 would have given it a fearsome velocity. I seem to remember there were some M60s regunned with a longer gun. Did that actually happen?
 

smurf

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The Swedish S-tank had an L/62 version of the standard L/50 105mm
which gave it "significantly higher" muzzle velocity, but I haven't a figure.
 

Przezdzieblo

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L/62 - a bit more than 1500 m/s, compared to ~1480 m/s of L/51. But this is APDS; I guess in case of APFSDS difference could be bigger.
 

Golfus

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Two superb books where you can find a ton of info:
- "Firepower, a History of the American Heavy Tank"
- "Abrams, a History of American Main Battle Tank"
both books by R.P. Hunnicutt. - Edit. Presidio

Regards from Seville
 

Pioneer

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Just stumbled across this -

In the late 1970s, two companies, Chrysler and General Motors, had competing prototypes of the M-1. General Motors had a large and traditional diesel engine in the tank, and Chrysler, which had tried and failed to develop turbine engine technology for cars and trucks for the commercial market, wanted to recoup their costs and put a risky and complicated turbine engine in their tank. The Army was ready to give the contract to General Motors, but politics intervened. In 1987, the Washington Monthly laid out the scene around the all-important decision of what tank was to be chosen:
On a July afternoon ten years ago, Lt. Colonel George Mohrmann sat at his desk on Capital Hill awaiting a phone call. As head of the Army’s congressional liaison office, he was ready to deliver a stack of sealed letters to members of Congress announcing the winning contractor in the multi-billion dollar competition to build the Army’s M-1 tank.
The two competing contractors, Chrysler and General Motors, offered a clear choice. Chrysler had built its tank around a radically different and unproven tank engine, the turbine; GM had used a more conventional diesel engine. The two tanks had undergone months of head-to-head trials at Aberdeen Proving Ground in Maryland.
GM had won.
The Army, it seemed, was not going to risk adding the M-1 to its growing list of overly sophisticated weapons that cost too much and don’t work. “We were sitting there poised to deliver [the envelopes],” Mohrmann recalls. “The decision [to select GM] had been made. We were just waiting for the Secretary of Defense to be briefed.”
The call, however, was surprising. The Pentagon told Mohrmann not to deliver the letters. The next day, Defense Secretary Donald Rumsfeld ordered a whole new round of competition. A week later, Rumsfeld turned the M-1 tank program upside down. He mandated that the tank be redesigned to incorporate the turbine engine. Four months later the award-which promised to generate $20 billion in sales – went to Chrysler and the Army was on its way to getting a weapon suited more for a paved interstate than a battlefield.
… That isn’t another story about the Army’s incompetent bureaucracy. “You can blame the Army for a lot of things,” says Anthony Battista, a staff member of the House Armed Services Committee, “but not for the troubles of the M-1.” Rather, it’s a story of how outside factors can overwhelm military considerations in the Pentagon decision-making process, how narrow interests – in this case the ailing Chrysler Corporation and, by a strange twist, the U.S. Air Force – can outweigh the need for a reasonably-priced and effective military. The M-1 was never just a weapon; it was also a bail-out package.

(Source: https://weaponsandwarfare.com/2015/08/15/general-motors-xm-1/)

Thought it was interesting, and yet so typically American (No insult intended!!)

Also found this snippet of info interesting -

The Americans set up a total of 117 criteria for the comparison test. The same criteria were also used to choose between the two versions of the XM-1 from Chrysler and General Motors. Some 40 criteria were not rated; of the remaining 77 criteria the Leopard [the West German supplied Leopard 2] met 61, the XM-1 48. Even in terms of this "go-no-go" procedure, the Leopard would have to be better than the XM-1, without any kind of statement concerning the extent to which a criterion was met. The 117 criteria were combined into 17 evaluation groups by the U.S. Army — and suddenly the picture of the comparison, which was also communicated to the public, appeared completely different. The Leopard met only 6 of the 17 requirements, the XM-1, on the other hand, met 16. For example, survival capability of the crew, and the equipment and the height of the vehicle, reliability and weight existed side by side with equal weighting in these 17 evaluation criteria.
(SOURCE: http://www.globalsecurity.org/military/world/europe/leopard2-design.htm )


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sferrin

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And yet the Abrams is one of the most successful, combat proven tanks in the world. I guess they did something right.
 

RAP

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Two superb books where you can find a ton of info:
- "Firepower, a History of the American Heavy Tank"
- "Abrams, a History of American Main Battle Tank"
both books by R.P. Hunnicutt.


You can get these and all his other books:

http://www.echopointbooks.com/our-titles/tanky-book

I believe they are print on demand, soft copy but the prices work for me.
 

overscan (PaulMM)

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Note : this is a topic about the XM1 project contenders, not discussion about the built M1 and its performance in recent wars. Posts split off and moved to new topic.
 
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