Medium Tank M11-8

M1: General
Date of manufacture May 1927 Total acceptances 1
Manufacturer Rock Island Arsenal Crew 4 men
M1: Dimensions
Combat weight 43,900lbs
19,900kg		 Height 115.5"
293.4cm
Length 258"
655cm		 Gun overhand forward 0"
0cm
Width 96"
240cm		 Ground clearance 22"
56cm
M1: Armament
Type Mount Ammunition Traverse Elevation
6 Pounder Flexible mount in turret 131 rounds 360°
(manual)		 Manual
.30cal Browning MG Cupola 4,200 rounds 360°
(manual)		 Manual
.30cal Browning MG Coaxial to 6 pdr 360°
(manual)		 Manual
M1: Armor
Assembly
Riveting
Maximum 1"
2.5cm		 Minimum .25"
.64cm
M1: Automotive
Engine Packard 1T-1330; 8 cylinder, 4 cycle, 60° vee gasoline
Horsepower 200@1,200rpm Fuel capacity 95gal
360L
Transmission Bevel and epicyclic gear, 4 speeds forward, 1 reverse
Steering Controlled differential, steering levers
M1: Suspension
Type Road wheels Drive sprockets
Coil spring 2 bogies/track;
4 wheels/bogie		 Rear drive
Idlers Shock absorbers
Adjustable at front of track None
M1: Track
Single pin, open, forged steel
Width 18"
46cm		 Pitch 8.125"
20.64cm
M1: Performance
Max level road speed 11.3mph
18.2kph		 Max trench 96"
240cm
Max grade 35° Max vertical obstacle 31"
79cm
Fording depth 24"
61cm		 Radius of action 50mi, roads
80km, roads

The medium tank M1 never entered service with the US Army. One soft steel pilot was made, since this cost $5,200 versus the $52,000 required to construct the armor plate. The design was standardized in February 1928, but its standardization was revoked in the spring of that year. The mount for the 6 pdr and coaxial MG permitted some movement of the weapons in addition to the turret rotation. The overhead valve Packard engine was developed to an Ordnance Department request and specifications. It had a bore of 5½" (14cm) and stroke of 7" (17.8cm) for a displacement of 1,330in³ (21.8L). An adjustable governor allowed the engine to spin to 1,500rpm, where it made 250hp and could propel the tank to 14mph (23kph).

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References

  1. Hunnicutt, R.P. Sherman: A History of the American Medium Tank. Navato, CA: Presidio Press, 1994. Reprinted with permission from Sherman, R.P. Hunnicutt ©1994, available from Presidio Press, 505B San Martin Drive, Suite 160, Navato, CA 94945.
  2. Tank Data, vol. 2. Aberdeen Proving Ground, MD: US Army Ordnance School, Jul 1958.
  3. AGF Board No. 2. Development of Armored Vehicles, volume 1: Tanks. 1947.
  4. Sola, Samuel, Vincent Bobkowski, and Kara Crocker. Weapon Mounts for Secondary Armament. Santa Monica, CA: G. O. Noville & Associates, Inc., April 1957.
  5. Crismon, Fred W. U.S. Military Tracked Vehicles. Osceola, WI: Motorbooks International, 1992.
  6. Kirk, William. "United States Medium Tanks." TANKS! 18 Jun 2002. 16 Jul 2002 <http://mailer.fsu.edu/~akirk/tanks/UnitedStates/mediumtanks/​MediumTanks.html>. TANKS!
  7. Pasholok, Yuri. "Medium Tank T1E1: Britain's Heir." Trans. Peter Samsonov. Warspot. 15 May 2020. Accessed 12 Dec 2020 <https://warspot.net/55-medium-tank-t1e1-britain-s-heir>.
  8. Neal, Robert J. A Technical and Operational History of the Liberty Engine: Tanks, Ships, and Aircraft 1917-1960. North Branch, MN: Specialty Press, 2009.
Last updated 10 Nov 2023.
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