|Please Support our Sponsors|
Light Armored Cars
Design, Development, Engineering and Production
Of Armored Cars (1940-1944)
This edition, edited, annotated and illustrated by David R. Haugh - Oregon USA
|A series of
37mm gun motor carriages had been developed during 1941-42 to provide
light, self-propelled mounts for 37mm anti-tank weapons. Developments
showed that a much heavier weapon than the 37mm gun was needed for
anti-tank purposes. With the termination of the program for medium and
heavy armored cars, these 37mm gun motor carriages were transferred from
anti-tank to reconnaissance vehicles.
experimental models tested, the light armored cars T21, T22, T22E1,
T22E2, T23, and T23E1; the T22E2 was standardized as the Army’s present
reconnaissance vehicle, the light armored car M8.
These vehicles will be
considered in the order given above.
|Car, Armored, Light, T21. The Studebaker T21 was originally designated as the Carriage, Motor, 37mm Gun, T43. (Photo: US Army)|
light armored car T21
was previously classified as the 37mm gun motor carriage T43, the
designation being changed in March 1942. Development of the 37mm gun
motor carriages T22 and T23 had been begun in October 1941 and pilot
models were being built by Ford Motor Company and the Fargo Division of
the Chrysler Corporation. The Studebaker Corporation desired to build a
vehicle in accordance with the characteristics set up for the T22 and
T23 and agreed to furnish a pilot model at no cost to the Government.
The vehicle was a 6x4 car
weighing 17,200 pounds (7809kgs) with load. It was armed with a 37mm gun
and a caliber .30 machine gun mounted coaxially in a turret with a
traverse of 360 degrees and an elevation of minus 12 degrees to plus 25
degrees. Frontal armor was .875 inch (22.3mm), side, top, and rear armor
was .375 inch (9.5mm) and turret armor was from .875 to 1.125 inches
(22.3 to 28.6mm). The car was powered by a Hercules 6-cylinder engine of
112 horsepower, and carried a crew of four men.
The report of the Special
Armored Vehicle Board stated that this car was satisfactory as an
armored reconnaissance vehicle but had defects of design and was not, in
December of 1942, ready for production. The using arms were accepting
the armored car M8 and had no use for a vehicle of almost the same
characteristics. The report of the Board noted that a good feature of
the car was the suspension. All six wheels were individually suspended,
using the parallelogram type suspension, with longitudinal torsion bars.
No further development was recommended, and the project was ended.
The development of light
armored cars T22, T22E1, T23, and T23E1 began in October 1941 in
accordance with requirements of the General Staff. The requirement was a
37mm self-propelled mount, to be a light, highly mobile, fast, lightly
armored, cross-country vehicle with a low silhouette and capable of mass
production at a minimum of cost.
characteristics of this proposed “tank destroyer” were outlined in a
memorandum from G-3 to G-4 of 30 July 1941 forwarded to the Chief of
Ordnance on 5 August. The vehicle was to weigh about 10,000 pounds
(4540kgs), be about 176 inches (4470mm) long, 72 inches (1829mm) high,
and 82 inches (2083mm) wide and be designed to carry a crew of four men.
It was to be
protected, turret and front, against caliber .50 A.P. ammunition
[A.P. = Armor Piercing]
at 250 yards (228.5m) and on the sides against caliber .30 ammunition at
100 years (91.4m). No top or bottom armor was contemplated. The armament
was to be one 37mm gun, in a combination mount with a caliber .30
machine gun in a 360 degree traverse turret, the elevation of the gun to
be from minus 10 degrees to plus 20 degrees. Additional armament was to
be one caliber .30 machine gun in a bow mount, and four caliber .45
The power plant was to be
designed to give a sustained speed of 15 miles an hour (24.2km/h) on a
10 percent grade, with a speed of 55 miles an hour (88.5km/h) on paved
roads and a cross-country speed of 35 miles an hour (56.3km/h). The car
was to be able to cross a vertical obstacle 12 inches (304.8mm) high,
and to be able to ford water to 24 inches (609.6mm) deep. The ground
clearance was to be 12 inches (304.8mm). The car was to drive on six
wheels and steer on four, and to have radio installation.
It was considered desirable
that the basic vehicle be adaptable for use also as a mobile mount for
ground machine guns in dual or quadruple mount, for caliber .50 machine
guns, for dual 20mm anti-aircraft cannon, for the 81mm mortar, or for
use as a cargo carrier for battlefield ammunition supply.
The construction of two
pilot models by two different manufacturers was approved. These models
were designated the 37mm Gun Motor Carriages, T22 and T23. Leading
automotive companies were asked to submit designs based on the above
requirement, and from the designs submitted, the Ford Motor Company was
selected to build the 37mm gun motor carriage T22, and the Fargo
Division of Chrysler Corporation was selected to build the 37mm gun
motor carriage T23. Contracts were let in November 1941.
To speed the development
process, and to determine the comparative merits of the four-wheeled and
six-wheeled vehicle, it was decided to build four-wheeled versions of
the T22 and T23, to be designated the T22E1 and T23E1 respectively, and
also to build two pilot models each of the four vehicles.
|Decisions were reached early in 1942 that antitank self-propelled mounts demanded greater firepower than that furnished by the 37mm gun. Since the tables of organization of the tank destroyer battalions included requirements for several types of light armored cars, and since the Cavalry also had such a requirement, it was recommended and approved in March 1942 that the designation of these vehicles be changed to “light armored cars”. On 21 April 1942, in view of the contemplated standardization of the T22 model, the development projects on the remaining three models were canceled. Since two models of each type were nearly completes, it was directed that they be completed for use as proof facilities.|
|Car, Armored, Light, T22. A 6x6 drive vehicle, only one Ford T22 pilot was completed. (Photo: US Army)|
|The pilot models had been completed in March 1942. The T22 built by the Ford Motor Company was a 6x6 vehicle having a tank-type hull but no frame, a Hercules JXD 110-horsepower engine in the rear, conventional leaf-spring suspension, conventional split type Timken axles, Warner Gear 4-speed transmission, and a 2-speed transfer case. The T22E1 was a 4x4 vehicle of similar construction. [A design study, no pilots of the four-wheeled T22E1 were actually built].|
|Car, Armored, Light, T23. In this view the vehicle is seen from the rear. The forward driver’s compartment shields could be folded down. (Photo: US Army)|
The T23 built by the
Chrysler Corporation was a 6x6 vehicle with a conventional truck-type
frame covered by an armored body, a Dodge 105 horsepower engine in the
rear, conventional leaf-spring suspension, conventional banjo-type
axles, Clark 5-speed transmission, and New Process 2-speed transfer
case. The T23E1 was a 4x4 vehicle of similar construction.
[A 4x4 vehicle based on
a truck type chassis, no pilot T23E1s were completed].
After completion of tests
at Aberdeen Proving Ground the light armored car T22 was driven to Fort
Knox, Kentucky for test by the Armored Force Board. Several major
redesigns were made, including redesign of the hull around the driver’s
compartment hatches, the addition of an armored sponson on each side of
the hull between the front and intermediate wheels to provide space for
two large radio sets, the addition of sand shields, and refinements in
the gun mount, traversing mechanism, and turret roller design. The
redesigned vehicle was redesignated Light Armored Car, T22E2.
|Car, Armored, Light, T22E2. Called Greyhound by the British, the E2 was the design, which would become the production M8. (Photo: Editor's collection)|
The vehicles as redesigned
were found acceptable as a reconnaissance vehicle for the Cavalry,
Armored Force, and the Tank Destroyer Command, and was standardized at
the Light Armored Car M8 in June 1942.
Tests of the original pilot
T22 at General Motors Proving Ground showed that the transmission and
transfer case gears required strengthening, the front axle required
strengthening, a vacuum booster was required for the brake system, and
improvements were needed in the engine cooling system.
Further changes made as the
result of tests of pilot and early production models are here
summarized. The gasoline tank was changed to the bullet-sealing type.
The armor plate with periscopes for commander and gunner, covering the
front half of the turret top was eliminated. Before the beginning of
production, and as a result of the recommendations of the Special
Armored Vehicle Board, the traversing mechanism was redesigned to
include two speed ratios; bullet-splash protection was improved; an
interphone system was added; and a change was made from hand-firing of
the turret guns to foot-firing. The front spring was strengthened. An
armor floor plate of .25-inch (6.35mm) thickness was designed for the
driver’s compartment for protection against antitank mines. A folding
pedestal type caliber .50 machine gun mount was installed on the turret
for antiaircraft protection.
The Ford Motor Company was
selected to build the light armored car M8 at their Chicago and Kansas
City branches. With cancellation of the
armored car T17, the program
intended for the Kansas City factory was transferred to the St. Paul
A production of 5,000
vehicles was planned; a total later raised to cover 6,000 vehicles. A
production order was issued 1 May 1942 for that number of cars. A second
production order covering 5,070 additional vehicles was issued 17 July
1942. This quantity was later reduced to 2,460 vehicles, making a total
of 8,460 vehicles under firm procurement.
Delay in acceptance of
contract by Ford Motor Company, since the terms prohibited the inclusion
of any sum for rehabilitation at the end of contract, and consequent
delay in placing orders for machine tools, tooling, and components
resulted in no production of vehicles in 1942.
|The Miller Printing Company of Pittsburgh, Pennsylvania was set up to manufacture 37mm mounts. Warner Gear Division of Borg Warner was chosen to provide transmissions and transfer cases. This facility had been expanded under the armored car T17 project and this expansion provided capacity for the M8 program as well. Engines were had from the Hercules Motor Company, Canton, Ohio.|
|Car, Armored, Light, M8. A production M8 being demonstrated in Washington D.C. (Photo: Editor's collection)|
Production began in March
1943, and peak production of 1,000 vehicles per month was reached in
November 1943, with a total of 4,229 vehicles accepted during 1943.
The production rate for
1944 was set at approximately 560 cars per month to provide a total
production of 6,672 vehicles in that calendar year. By the Army Supply
Program of 1 February 1944, the total authorization for 1944 was reduced
to 3,383 cars, with a total authorization for 1945 of 2,401 cars.
Procurement was adjusted to the new requirement. Spare parts canceled by
readjustment were picked up by requisition from Stock Control Division
to apply on all-time buy.
W374-ORD-1744, Supplement No. 1, covering $15,000,000.00 was accepted by
Ford Motor Company on 23 July 1942. Supplement No. 2, covering
$4,500,000.00 on Letter-Purchase Order for 5,070 additional vehicles was
accepted 27 July 1942.
By Amendment No. 1 to
Production Order T-3809 of 29 September 1942, covering production of
6,000 vehicles, additional funds of $126,480,000.00 were authorized for
finalization of contract. The estimated cost per vehicle was $18,000.00
plus a fixed fee of $1,080.00 per vehicle
[This amount did not
include the costs of weapons and radios];
this to be renegotiated after 3,000 cars had been accepted.
On reduction of Production
Order T-4175 by amendment No. 1 to 2,460 vehicles, funds were allotted
for completion of the contract. The armored utility car M20 was
developed from the light armored car M8 as a companion vehicle. The Tank
Destroyer Command recommended that, for use of the M8 as a command car,
the 37mm gun mount be removed and a caliber .50 machine gun be mounted
in a ring mount on top of the turret, and that the turret and top plate
of the be removed and the interior be rearranged. For use of the basic
M8 as personnel, ammunition, and cargo carrier, the same changes were
recommended. For use as an antiaircraft vehicle, it was recommended that
a Maxson multiple machine gun turret be used, employing the original
turret ring with a special Maxson type turret mount.
|Recommendation was made that pilot models of each of these variations from the original vehicle be constructed, and that the antiaircraft vehicle be designated Multiple Gun Motor Carriage, T69, that the command vehicle be designated Armored Command Car, T26 and that the personnel and cargo vehicle be designated Personnel-Cargo Carrier, T20.|
|Car, Utility, Armored, T26. The T26 was also a 6x6 vehicle. (Photo: US Army)|
It was later found possible
to meet the requirements indicated for personnel carrier T20 and armored
car T26 in one vehicle and the designation of this design, fulfilling
both needs, was changed to Armored Utility Car T26. This was
standardized in May 1943 as Armored Utility Car M10. To avoid confusion
with the 3-inch gun motor carriage M10 the designation of this car was
then changed to Armored Utility Car M20.
|Car, Utility, Armored, M20. A very successful vehicle, M20s are still in service today around the world, albeit much modified. (Photo: US Army)|
The chassis, running gear,
and lower hull of the armored utility car M20 were identical with those
of the light armored car M8. The turret on the upper hull of the M8 was
removed and the sidewalls extended upward about 15 inches (381mm) to
form a rectangular crew compartment. Above the crew compartment was
mounted the Caliber .50 Ring Mount, M49. Provision was made for carrying
a crew of from five to seven men. Crew compartment seats and a bulkhead
between driving and crew compartment may be removed, providing space to
carry about 3,000 pounds (1362kgs) of cargo.
All improvements found
needed on the M8 were incorporated simultaneously on the M10/20.
Production of the armored utility car, M20 was begun in July 1943 at the
Chicago branch of the Ford Motor Company.
The Army Supply Program of
1 August 1943 revised requirements for this vehicle from 4,000 in 1943
to 3505, and from 2,622 in 1944 to 567. Procurement was adjusted in
accordance with these changes. A total of 1,624 cars were accepted in
1943 the difference between this quantity and the requirements being
carried forward and added to the requirements for 1944.
Production for 1944 was
scheduled at about 215 vehicles per month. The Army Supply Program of 1
February 1944 reduced the total requirement for that year to 766
vehicles, and authorized procurement of 785 vehicles in 1945.
Procurement was again adjusted in accordance.
A change in the Army Supply
Program of 18 July 1944 increased the procurement authorized for 1944
from 766 vehicles to 1337, and increased the procurement authorized for
1945 from 785 vehicles to 806. Remarks were made, and procurement was
once again adjusted to conform to these requirements.
|The project for this vehicle [the M20] is still in existence early in 1946 and present schedules are being maintained.|
|Carriage, Motor, Multiple Gun, T69. After testing, the Antiaircraft Command decided to stick with their current half-track based multiple gun units. (Photo: US Army)|
The Multiple Gun Motor
Carriage T69 was developed at the request of the Tank Destroyer Command,
using the chassis of the Light Armored Car M8.
Engineering studies made by
the Ordnance Department indicated the possibility of mounting four
caliber .50 machine guns in a power operated turret capable of 360
degree traverse and elevations from minus ten degrees to plus 85
degrees. The power control mechanism used in the M45 mount, in
production, was found to be adequate for the proposed turret. In
November 1942 the W.L. Maxson Corporation, of New York City, began
design and construction of a pilot caliber .50 machine gun turret. A
modified armored car M8 chassis, with the electrical system changed from
12 to 24 volts, and with the addition of an auxiliary motor-generator
capable of supplying 50 amperes at 24 volts, was furnished by the Ford
Motor Company for incorporation of the new turret.
By direction of Army Ground
Forces, responsibility for service testing of the pilot T69 was placed
with the Antiaircraft Command rather than with the Tank Destroyer
The pilot T69 was tested at
Aberdeen Proving Ground and was returned to the W.L. Maxson Corporation
for incorporation of new power feed assist for feeding the two outboard
guns, improved disposition of empty cases, strengthening of the sight
mounting, and improving the gunner's seat.
With modifications, the T69
was returned to Aberdeen Proving Ground for additional firing tests, and
was tested by the Antiaircraft Artillery Board at Camp Davis, North
Carolina, in comparison with the standard multiple gun motor carriage
M16. The report of this Board indicated that the T69 was inferior to the
M16 in weight-carrying capacity, mobility, space provisions, centering
of fire of the mount, and effectiveness of fire.
The Office, Chief of
Ordnance-Detroit believes, however, that the T69 is superior to the M16
in its greater armor protection for the crew, vehicle, and components,
in reduction of crew personnel from five to three men, and the fact that
the T69 has a manual control which could permit effective fire against
ground targets. Further advantages are ability to engage enemy aircraft
with at least two guns firing continuously for a longer time, and
greater flexibility of electric power available for operation of the
turret by provision of a generator on the vehicle engine in supplement
of the auxiliary generator unit.
|The Antiaircraft Artillery Board recommended no further consideration of the T69 and the project was closed.|
are several US vehicles that were either produced or under consideration
that were missed in the original history. Below are photos and a brief
description of some of those vehicles.
|Dodge Armored Car developed by Troop A, 1st Armored Car Squadron, 1st Cavalry Division, at Fort Bliss, Texas in 1930. This is one of at least three versions. All had the same armament of one .30 caliber machine gun in an aircraft ring mount. (Photo: Editor's collection)|
|Armored Car developed for the 112th Cavalry in 1932. Built and designed by Capt. John Dunlap, of the Machine Gun Troop, 112th Cavalry. (Photo: Editor's collection)|
Car, Armored, T8. A total of two Armored Car, T8 were completed based on a Chevrolet chassis, USA W-1307 and USA W-1308. USA W-1307 was later converted to the Armored Car, T9. (Photo: Editor's collection)
|Car, Armored, T9. The T9 used the armored body from the T8 series placed on a Plymouth chassis. (Photo: Editor's collection)|
|Above: Car, Armored, M38. Although type classified, the M38 was too late to see combat during WWII and only a very few vehicles were completed. Above an M38 is fitted with the turret from the M24 Light Tank series. In many ways this was similar to what would later be the British Saracen armored car. (Photo: US Army)|
|Previous Page||Return to Article Index||Next Page|
|Copyright: David Haugh - August 2006|