American M8 Howitzer Motor Carriage

M8 Howitzer Motor Carriage.

The 75 mm Howitzer Motor Carriage M8 was a self-propelled howitzer vehicle of the United States developed during World War II.

The first design for a close support howitzer on an M5 tank chassis was the T41, which had the howitzer in the hull front. This did not progress past the mock-up stage as the crew would not have been sufficiently protected and design work started on the T47. It was developed on the chassis of the then-new Light Tank M5 (Stuart VI). The prototype was designated the 75 mm Howitzer Motor Carriage T17E1 It had the standard M5 turret removed and replaced with a larger open-topped turret; as a result, the drivers' hatches had to be moved from the hull roof to the glacis plate. After a mock-up had been produced, it was ordered into production as the 75 mm Howitzer Motor Carriage M8. The M8 was based upon the Light Tank M5, but incorporated several changes. Like the Light Tank M5, the M8 had a crew of four; commander, gunner, driver, and assistant driver/loader. When the M8 was in action, the commander positioned himself at the antiaircraft machine gun and directed his crew, the gunner sat in the turret on the right side of the howitzer, the assistant driver/loader moved up from his seat in the right front hull, and the driver stayed at his position.

Due to the usage of a new turret, the crew hatches in the hull roof for the driver and assistant driver/loader were deleted and replaced by a pair of vision flaps in the glacis. Since the glacis hatches were too small to disembark through, these two crew members had to leave the vehicle through the open-topped turret. The driver and assistant driver/loader were provided with periscopes for visibility. In November 1944, the Ordnance Department gave the M8 the name General Scott, after American general Winfield Scott.

As the M8 was based upon the Light Tank M5 (itself a descendant of the Light Tank M3) it had relatively thin armor. The lower hull armor ranged from 1 in (25 mm) to 1.125 in (28.6 mm) on the sides to 1.75 in (44 mm) on the lower front and 1.0 in (25 mm) on the lower rear. The lower hull sides were vertical, while the lower hull front was sloped at 18 degrees from the vertical, and the lower hull rear, which protected the engine and radiator, was sloped at 17 degrees from the vertical. The hull floor ranged from 0.5 in (13 mm) thick at the front to 0.375 in (9.5 mm) thick at the rear. The glacis plate of the M8 was sloped at 45 degrees from the vertical and was 1.125 in (28.6 mm) thick. The upper hull sides, like the lower hull sides, were vertical and 1.125 in (28.6 mm) thick at the front, thinning to 1 in (25 mm) thick at the rear. The upper rear hull was a vertical plate, 1 in (25 mm). The plate sloped at 50 degrees for a short distance before it met the hull roof, which was uniformly 0.5 in (13 mm) thick, and flat.

The turret of the M8 was of cast steel. It was 1.5 in (38 mm) thick at the front, which was rounded, sloping from 0 to 63 degrees from the vertical. The sides and rear were 1 in (25 mm) thick and sloped at 20 degrees from the vertical. The cast gun shield which covered the barrel of the 75 mm Howitzer M2/M3 was 1.5 in (38 mm) thick and rounded.

The armament of the M8 consisted of a new open-topped turret armed with a 75 mm M2 howitzer, later a 75 mm M3 howitzer. The M8 carried 46 rounds of 75 mm ammunition; 11 rounds at the right rear of the fighting compartment, 20 rounds at the left rear of the fighting compartment, 9 rounds in the left hull sponson, and 6 "ready" rounds stored between the driver and assistant driver's positions. The most common types of ammunition carried were the M89 white phosphorus shell and the M48 high explosive shell. Unlike the standard M5 light tank, the M8 featured no hull-mounted or coaxial Browning M1919A4 .30 caliber machine gun. A Browning M2HB .50 caliber machine gun with 400 rounds was mounted on the right rear corner of the turret for local defense and anti-aircraft purposes. For self-defense, the vehicle driver was provided with a Thompson submachine gun, while the other three crew members were issued M1 carbines.

1,778 of the Howitzer Motor Carriage M8 were produced by the Cadillac division of General Motors from September 1942 to January 1944.

Production of M8 Howitzer Motor Carriage

Month	Number built	Serial number(s)	Registration number(s)
September 1942	1	1	4051234
October 1942	24	2-25	4051235-4051258
November 1942	101	26-126	4051259-4051359
December 1942	247	127-373	4051360-4051606
January 1943	160	374-533	4051607-4051766
February 1943	160	534-693	4051767-4051927
March 1943	160	694-853	4051928-4052086
April 1943	160	854-1013	4052087-4052246
May 1943	160	1014-1173	4052247-4052406
June 1943	160	1174-1333	4052407-4052566
July 1943	62	1334-1395	4052567-4052628
August 1943	62	1396-1457	4052629-4052690
September 1943	62	1458-1519	4052691-4052752
October 1943	62	1520-1581	4052753-4052814
November 1943	62	1582-1643	4052815-4052876
December 1943	60	1644-1703	4052877-4052938
January 1944	75	1704-1778	4052939-4053011
Total	1,778

The 75 mm Howitzer Motor Carriage M8 was assigned to the Assault Gun Troops of Cavalry Reconnaissance Squadrons in order to give them close support against enemy fortified positions. The high elevation (40 degrees) of the howitzer was useful for hitting enemies emplaced on the sides of hills. The M8 was used in the Italian Campaign, the Western Front, and in the Pacific Theater of Operations by the US Army and on the Western Front by the French Army. It was also used by the French Union and State of Vietnam during the First Indochina War. It stayed in French service until the 1960s and saw service in Algeria.

Type: Self-propelled artillery

Place of origin: United States

In service: 1942-1960s

Designer: U.S. Army Ordnance Department

Designed: 1942

Manufacturer: Cadillac division of General Motors

Produced: September 1942–January 1944

Number built: 1,778

Weight: 34,600 lb (15.69 metric tons) combat weight

Length: 16 ft 4 in (4.98 m) with sand shields

Width: 7 ft 7.5 in (2.32 m) with sand shields

Height: 8 ft 11 in (2.72 m) over antiaircraft machine gun

Crew: 4 (Commander, gunner, driver, assistant driver/loader)

Armor: 0.375 to 1.75 in (9.5 to 44 mm)

Main armament: 75 mm Howitzer M2/M3 in Mount M7; 46 rounds

Secondary armament: .50 caliber (12.7 mm) Browning M2HB machine gun; 400 rounds

Engine: Twin Cadillac Series 42 inline 6 cylinder 4-stroke gasoline engine; 220 hp (164 kW) total at 3,400 rpm; 110 hp (82 kW) per engine

Power/weight: 14.02 hp/metric ton

Transmission: Twin Hydramatic; 4 speeds forward, 1 reverse

Suspension: Vertical volute spring suspension (VVSS)

Ground clearance: 14 in (0.35 m)

Fuel capacity: 89 US gallons (340 liters)

Operational range: 100 mi (160 km) on road

Speed: 36 mph (58 kph) on road

Steering system: Controlled differential, steering levers

Variants

75 mm Gun Motor Carriage M8A1: A lightweight tank destroyer prototype that used an M5A1 light tank hull. The M8's turret was paired with a 75 mm gun M3 as used on the M4 Sherman tank. The project was later cancelled with the development of the M18 Hellcat.

Users

United States: U.S. Army

France: French Army

South Vietnam: Army of the Republic of Vietnam (ARVN)

Cambodia: Khmer National Army (FANK)

Kingdom of Laos: Royal Lao Army

Republic of China: Republic of China Army (ROCA)

Tunisia: Tunisian Army

 

M8 75mm Howitzer Motor Carriage, General Motors Proving Ground, 4 November 1943.

M8 75mm Howitzer Motor Carriage, General Motors Proving Ground, 4 November 1943.

Schematic cutaway view of the 75mm Howitzer Motor Carriage M8.

Diagram of 75mm and .50 cal. ammunition storage in the 75mm Howitzer Motor Carriage M8.

Knocked out M8 Howitzer Motor Carriage M8 being retrieved by wrecker.

M8 Howitzer Motor Carriage, Philippines.

M8 Howitzer Motor Carriage, Philippines.

M8 Howitzer Motor Carriage on Saipan, June 1944.

M8 Howitzer Motor Carriage, 113th Cavalry Reconnaissance Squadron, Belgium, September 1944. The nearest vehicle has a hedgerow cutter installed.

M8A1 Howitzer Motor Carriage re-armed with M3 75mm Gun.

M8 Howitzer Motor Carriage.

The drivers' doors in the hull front plate are obvious in this M8 Howitzer Motor Carriage; the drivers had periscopes in the hull roof as well for driving while buttoned up. The 75mm howitzer was covered by a long flash deflector, and the muzzle of the howitzer barrel can be seen down inside the flash hider. This vehicle is equipped with sand shields and brackets for stowing track grousers on the turret, which indicate it's a later production. The mount for the .50 cal M2HB MG can be seen towards the rear of the open-topped turret, although the gun itself is absent.

This top view shows the internal arrangements of the open-topped turret of the M8 Howitzer Motor Carriage.

The dual drivers' controls of the M8 Howitzer Motor Carriage.

Details of the firing controls on the M8 Howitzer Motor Carriage.

Details of the breech end of the howitzer and its mount on the M8 Howitzer Motor Carriage.

The elevation and traverse controls of the M8 Howitzer Motor Carriage.

An exploded view of the M8 Howitzer Motor Carriage's trailing idler wheel.

The action posts on the M8 Howitzer Motor Carriage: The chief of section is manning the machine gun and monitoring the fall of the rounds. The gunner is just in front of the chief, and the loader is on the opposite side of the ordnance, leaving the driver as the only man in the hull. When mounted and not in action, the gunner would occupy the assistant driver's position, the loader would man the machine gun, and the chief would place himself on the turret's right side.

M8 Howitzer Motor Carriages, partially concealed by a hedgerow, preparing to fire on enemy positions near Marigny, France, July 1944.

M8 Howitzer Motor Carriages near Vic-sur-Aisne, France, September 1944.

M8 Howitzer Motor Carriage (s/n 4052227), "Laxative," with Cullin hedgerow cutter, Barenton, France, August 1944.

GMC CCKW 2½-ton 6x6 trucks and an M8 Howitzer Motor Carriage are passed by a French Moroccan Goumier with a pack mule, on the road to Castleforte, Italy, May 1944.

M8 Howitzer Motor Carriage.

M8 Howitzer Motor Carriage training in 1943.

M8 Howitzer Motor Carriages, manned by African American soldiers of the 758th Tank Battalion, firing in support of 442nd Regimental Combat Team, who were making an attack northward along the mountain ridges of Mount Belvedere toward the towns of Massa and Carrara, Italy, 8 April 1945.

M8 Howitzer Motor Carriages, manned by African American soldiers of the 758th Tank Battalion, firing in support of 442nd Regimental Combat Team, who were making an attack northward along the mountain ridges of Mount Belvedere toward the towns of Massa and Carrara, Italy, 8 April 1945.

Armored vehicles of the 46th Tank Battalion, 13th Armored Division, 1943. From left to right: Ford GPA Amphibian, MB/GPW Jeep, M2/M3 Halftrack, M5A1 Light Tank, M4 Medium Tank, M8 Howitzer Motor Carriage, M3A1 Scout Car, M6 Gun Motor Carriage.

M8 Howitzer Motor Carriage crosses a Tennessee river during maneuvers in 1943, towing an ammunition trailer.

American troops and vehicles on a road in Belgium, 8 September 1944. Left to right: Jeep, M8 Howitzer Motor Carriage, and M5 Light Tank.

M8 Howitzer Motor Carriage firing on German positions, Karlsbrunn, Germany, March 1945.

Crowds of French line the Champs Elysees to view Allied troops and vehicles pass through the Arc du Triomphe, one day after Paris was liberated on 25 August 1944. Halftracks, M8 Howitzer Motor Carriage (left).

Close-up of the M8 Howitzer Motor Carriage in the above photo.

M8 Howitzer Motor Carriages and infantrymen of 77th Infantry Division, Tenth Army on Okinawa.

M8 Howitzer Motor Carriage on display at the Musée des Blindés in Saumur, 8 August 2006.

M8 Howitzer Motor Carriage on display in the museum Maurice Dufresne, Azay-le-Rideau, Indre-et-Loire, France.

M8 Howitzer Motor Carriage is moved from Aberdeen Proving Ground, 6 August 2009. Sixty ordnance treasures made the 200-mile trip down treacherous Interstate 95 to Fort Lee, Virginia, during Phase I of the Ordnance Museum relocation.

This M8 Howitzer Motor Carriage arrived in the first phase of the move of the U.S. Army Ordnance Museum collection from Aberdeen Proving Ground, Maryland, to its new home at Fort Lee, Virginia, 4 August 2009. Workers unloaded approximately 60 tanks and artillery pieces. This is the largest move in the history of the U.S. Army Museum system, according to Dr. Joseph Rainer, Ordnance Museum director.

M8 Howitzer Motor Carriage coming ashore through surf. Still from film footage.