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
Height 115.5"
Length 258"
Gun overhand forward 0"
Width 96"
Ground clearance 22"
M1: Armament
Type Mount Ammunition Traverse Elevation
6 Pounder Flexible mount in turret 131 rounds 360°
.30cal Browning MG Cupola 4,200 rounds 360°
.30cal Browning MG Coaxial to 6 pdr 360°
M1: Armor
Maximum 1"
Minimum .25"
M1: Automotive
Engine Packard 1T-1330; 8 cylinder, 4 cycle, 60° vee gasoline
Horsepower 200@1,200rpm Fuel capacity 95gal
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"
Pitch 8.125"
M1: Performance
Max level road speed 11.3mph
Max trench 96"
Max grade 35° Max vertical obstacle 31"
Fording depth 24"
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 The design was standardized in February 1928, but its standardization was revoked in the spring of that year.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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Last updated 10 Nov 2023.
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