Big Gun

THOMAS FLEMING’S ARTICLE “TANKS” (Winter 1995) was fascinating in recounting the U.S. Army’s more than sixty-year struggle to develop a truly world-class fighting vehicle, but a gap in the story is evident. The marvelousIy detailed cutaway illustration of the M1A1 Abrams tank, with more than thirty callouts for its components, fails to pick out the raison d’être for the two-million-dollar vehicle: its main weapon and ammunition.

That ungainly-looking cantilevered tube protruding over the port side of the tank is a marvel of the weaponeer’s art. It is a smooth-bore, very highpressure cannon, capable of firing routinely at pressures greater than 80,000 psi. Its predecessor, the M-60 tank, fired routinely at only 50,000 psi. That high-pressure capability was a direct outgrowth of the 120-mm Delta gun program of the 1960s at the Watervliet and Picatinny U.S. Army arsenals.

The business end of the entire system is the munition, which travels the three thousand meters to its target and delivers the killing blow. This too is a marvel of the weapon engineer’s art. The kinetic-energy penetrating shot is launched from the cannon at more than a mile a second after undergoing a launch acceleration of more than 75,000 g’s. Its construction and ability to penetrate armor are astonishing but probably still classified.

The history of these weapons developments has not been recounted in the open literature but probably should be. It is a model of applied technology.

Sidney S. Jacobson
Chester, N.J.
(The writer is a retired developer of antiarmor munitions at the Picatinny Arsenal.)

Big Gun

I LIKED YOUR ARTICLE BUT WAS SUR prised you didn’t give the story of how the tank got its name. While the device was under development, Britain was fighting the Ottoman Empire in the Near East. In order to conceal the purpose of the large, riveted-steel machine, it was referred to as a Mesopotamian Water Carrier, a tank for the transportation of water through the arid deserts. The name stuck, and the device went through the usual trials and tribulations of a new development in a hurried atmosphere.

Lloyd A. Buchalter
Wallkill, N.Y.

Shrill Talkies

AS A FILMMAKER I THOROUGHLY EN joyed Curt Wohleber’s article on movie sound (“How the Movies Learned to Talk,” Winter 1995). He mentions compressed air. One of the synchronized-disk systems oscillated a pneumatic gate in a stream of compressed air that fed trumpetlike speaker horns, analogous to the vacuum-tube grid that controlled plate current in later electronic amplification circuits. I can remember (barely—I was pretty young) how at resonant frequencies deafening hoots and shrieks resulted as the speaker system occasionally turned into a huge reed instrument.

Jack E. Gieck
Akron, Ohio

The Wheel Turns

IN “HENRY FORD’S BIG FLAW” (BY JOHN M. Staudenmaier, S.J., Fall 1994), a photo on page 36 shows a cluster of right-hand-drive vehicles. There must be a story there. How, when, and why were American vehicles designed with left-hand drives?

W. Robert Schwandt
Decatur, Ill.

The editors reply : As John B. Rae writes in The American Automobile : “A minor but significant change in styling that occurred about 1910 was shifting the steering wheel from the right to the left side of the car. This change represented an abandonment of the practice of imitating European usage for the sake of prestige and an adaptation to the conditions of American driving.” As cars became more dense on American roads, thanks in large part to the Model T, and started passing one another often in opposite directions, the advantages of left-hand drive became manifest.

Champions Of Chama

MY SINCERE CONGRATULATIONS TO Peter Tuttle for his excellent article on the Cumbres & Toltec Scenic Railroad (“The Lost Language of Trains,” Winter 1995). I’d like to mention the Friends of the Cumbres & Toltec, a group of dedicated volunteers who travel to Chama and Antonito each summer at their own expense to devote several days to restoring and preserving cars and structures at Chama and along the sixty-four-mile right-of-way. The Friends have purchased narrowgauge tank cars in Alaska and returned them to the crude-oil loading rack at Chama, where they were in use before World War II; they have also rebuilt the snowshed at the Cumbres summit and painted and renumbered rail cars. More than a hundred members attend each of the three-day work sessions, putting in long days and furnishing many of their own tools, under the watchful eye of the State Historic Preservation Office. Materials are paid for by fund-raising events. Anyone who wishes to become a part of the restoration and preservation of railroad history may write to Friends of the Cumbres & Toltec Scenic Railroad, 5732 Osuna Road NE, Albuquerque, NM 87109.

Malcolm Mackey
Flagstaff, Ariz.