At the beginning of World War II, in 1939, there was very little military interest and investment in national defense, and as a result, the army was inadequate and equipment was outdated due to the continual reduction of funds for military expenditures. After the demobilization that followed the end of World War I, the army consisted of just over 170,000 men, vehicles were scarce, and funds for training were a tiny fraction of the budget. The service rifle was the Springfiled 1903, now decidedly outdated, the artillery was obsolete, while anti-tank and anti-aircraft equipment was almost nonexistent. Army Chief of Staff General George Marshall, in particular, tried to explain to politicians that the Army's needs for expansion and modernization were essential to national defense.
With the outbreak of war in Europe, U.S. President Franklin Delano Roosevelt declared the country in a limited state of emergency, authorizing a slight increase of 17,000 men in the Army, the purchase of vehicles and equipment, and increased exercises both for the state militia and to provide experience for senior officers and general staff personnel through Regular Army Corps maneuvers. The majority of the American public, however, was imbued with a non-interventionist view of the war that was breaking out in Europe, especially when the situation seemed to have stabilized after the Wehrmacht's conquest of Poland.
Everything changed, even in public opinion, when, between May and June 1940, the German army overwhelmed France and England, after the defeat at Dunkirk and the almost total loss of heavy equipment left on the French coast, found itself on the brink of invasion, while the Royal Air Force fought fiercely in the skies. By May 1940, at the President's request and initiative, Congress had appropriated nearly $1.5 billion, increasing the Army to 375,000 men and enabling it to begin acquiring new artillery, building new ammunition factories, and beginning production of equipment for soldiers. By the fall, manpower levels in both the Army and Air Force would begin to grow more substantially, with additional funding allowing them to plan for the modernization of the aircraft fleet.
In the summer of 1940, between August and September, the state militia came under federal control, the President signed the Conscription Act, and the construction of the first training camps for future recruits began. In practice, with the Conscription Act, the U.S. Army could grow to nearly 1.5 million personnel.
On March 11, 1941, the Lend-Lease Act was passed, allowing Roosevelt to "sell, exchange, lease, loan, or otherwise dispose of to any government whose defense is deemed essential by the President of the United States. The first recipient of $1 billion was England, in October 1941.
All of America's economic, productive, and organizational power had begun to be deployed, and by July 1941 the strength of the armed forces was 1,400,000 men, divided into 456,000 in 28 divisions, 43,000 in armored forces, 308,000 in 215 specialized regiments of land artillery, 167,000 in aviation, 46,000 in harbor defense, 120,000 men in overseas garrisons including Alaska and Newfoundland, 160,000 in 550 military installations including depots and embarkation ports; the remainder were recruits in training centers which, like those for the Army, had been built and set up very quickly during the winter of 1940-1941.
THE MAIN INFANTRY ARMAMENT
The Garand M1 was the first .30-caliber (7.62-millimeter) gas-operated semi-automatic rifle fed by an eight-shot .30-06 Springfield "en bloc" clip.
It was already in production by 1937 and had been mass-produced and distributed by 1940, after defeating its direct competitor, the Johnson 41.
Considered the rifle that won World War II, some six million were produced during its long production run.
The Winchester M1 was a short, lightweight semi-automatic carbine designed for men in support roles, such as tankers, artillerymen, and engineers, as well as NCOs on the front lines.
Deliveries began in mid-1942, and it was a medium-range weapon fed by 15- and 30-round .30 Carbine magazines. Approximately seven million were produced.
The Thompson submachine gun, in its early M1 and standard M1A1 military versions, was a civilian machine gun designed by John Thompson in 1919 during Prohibition. Although it was a heavy weapon, it had a high rate of fire and excellent close-combat effectiveness due to the high stopping power of its .45 ACP (11.5 mm) caliber ammunition. Approximately two million were produced.
The Browning Automatic Rifle (BAR) was used in the latter stages of World War I and upgraded to the M1918A2 model in 1938. It was then adopted as a squad weapon. This gas-operated weapon intercepted the gas produced by the gunpowder to eject the bullet in a small hole in the barrel just before the muzzle. The pressure of this gas acted on a piston that retracted the bolt and allowed the extractor to remove the cartridge case. A spring then allowed a new round to be inserted into the barrel. It fired standard American .30-caliber ammunition.
The M3 submachine gun, introduced in 1942 and nicknamed the "Grease Gun" or "Grease Pump" because of its shape, was designed as a close-combat weapon to replace the Thompson. The Thompson was extremely expensive and complex to produce, and the M3 was much lighter and less bulky. Like the British Sten and the German MP40, it was largely made of stamped metal and produced in two calibers: 9mm for partisan forces in Europe (the Germans used 9mm ammunition for MP pistols and machine guns) and .45 ACP for tankmen and infantry troops.
There were three machine guns in service:
The Browning M1917A1, a water-cooled machine gun, was first used during World War I as the M1917. It was fed by 250-round canvas belts of standard American .30-caliber ammunition.
The Browning M1919 was an air-cooled medium machine gun that entered service in 1919. It was mainly used in World War II in its A1, A3, A4, and A6 versions, with the A6 being used towards the end of the war. It was fed by 250-round belts of standard American .30-caliber ammunition.
The Browning M2, produced in 1933, was an air-cooled heavy machine gun used in World War II. It was fed by metal-handled magazines and fired .50 caliber (12.7 mm) ammunition. The airborne version, the Model M1921, dates from this period.
The U.S. Armored Forces were born between August 1940 and June 1941. The Armored Corps School and Training Center were established primarily at Fort Knox and Fort Benning. By the time the United States entered the war following the Japanese attack on Pearl Harbor on December 7, 1941, four armored divisions were available. During the interwar period, there was little support for tank development. By the time the U.S. entered the war, only two models were in service: the M2 medium tank, designed in 1937, and the M2 light tank, designed in 1935. By 1940, these models had been developed into the M2A1 medium tank and M2A4 light tank, respectively. In 1941, due to the inadequacy of the M2 versions and pending the development of a new tank capable of competing with new European models, the intermediate M3 Lee light tank was produced. Its armament consisted of a 37mm gun on the turret and a 75mm gun mounted below the turret, next to the driver. This gun could only fire forward with a maximum total swing of 30 degrees.
The M4 Sherman medium tank did not enter service until 1942 and became the U.S. Army standard until 1955. Nearly 50,000 were produced in its many variants. The initial models featured a single cast hull and a Wright R-975 Whirlwind 16-liter radial aircraft engine. The turret-mounted gun was a 75mm gun, replaced in 1944 by a much more powerful 76.2mm gun needed to cope with the German Panther IV and Tiger tanks.
Tankers nicknamed the Sherman the "Ronson" because it was gasoline-powered and poorly protected by armor. This made it prone to catching fire when hit by the powerful German guns, even from a distance.
Last photo: From left: two Harley Davidson WLA's, an amphibious Ford GPA Seep, Willys, M3 Halftruck, M3 Stuart, M4 Sherman, M8 with howitzer, an armored M3.
Bibliography:
Sherman medium tank 1942-1945 by Steve Zaloga e Peter Sarson
Thompson submachine gun by Desert Pubblications
The Garand M1 and the M1 Carbine by Bruce N. Canfield
US Army Photo Album by Jonathan Gawne
The American Arsenal by Greenhill Military Paperback
THE UNITED STATES AIR FORCE
During the interwar period, aviation suffered from limited resources and experienced slow development fraught with obstacles. Aviation was divided into two branches: classical aviation under the Army and naval aviation under the Navy. This division persisted until September 18, 1947, when the National Security Act established the Department of Defense, comprising the Army, Navy, and Air Force.
At the start of the war in Europe, the U.S. Air Force - called the United States Army Air Corps (USAAC) until 1941- had just under 1,000 aircraft. Unlike Germany and Italy, however, American military thinking had brought U.S. aircraft companies to a very advanced stage in the development of large strategic bombers. The German invasion of France and President Roosevelt's declaration of a limited state of emergency led to the rapid development of aviation in the U.S., reaching 54 battle groups and 167,000 active-duty troops by July 1941.
When the United States entered the war, one of the most important fighters in its Air Force was the North American P-51 Mustang. Delivered to the Allies under different names as a result of the Lend-Lease Act, the Mustang entered service in May 1941. The P-51 represented a fusion of American aircraft engineering and British engine design. Early 1940 models were powered by a 1,000-horsepower American axial-flow Allison V1710 engine. Eventually, the Rolls-Royce Merlin engine, capable of developing 1,300 horsepower, was adopted, partly due to advances in fuel technology. In 1942, Packard produced the V1650 under license from Rolls-Royce. Capable of developing 1,650 hp, it equipped the P-51, making it one of the best fighters of World War II. More than 15,000 P-51s were produced in all its versions. With a range of 3,300 kilometers, it began to make a difference in the European theater at the end of 1943 as an escort for heavy bombers attacking Germany, significantly decreasing their losses as the P-51 was able to match the German Fw 190.
Two other aircraft with which the U.S. Air Force entered the war were the Curtiss P-40 and the Bell P-39. Designed in 1937, the Curtiss P40 entered service in 1941. Powered by an Allison V1710 engine, nearly 14,000 were produced. While the P-51 and P-39 could also be used as fighter-bombers, the Bell P-39 Aircobra was a pure fighter. Manufactured by Bell, it entered service in 1941 with an Allison V1710 engine positioned behind the cockpit. It was a heavy aircraft that was slow to climb. The Soviets highly prized it, and more or less half of the production of just under 10,000 was destined for them.
In the bomber field, the first twin-engine medium bomber was the Martin B26 Marauder. The first of just over 5,000 produced were delivered in 1941, but the first operational B26s entered service in 1942. Powered by two powerful 2,000 hp Pratt & Whitney R2800 engines, it was well armed with six .50 caliber machine guns, could carry over 1,300 kg of bombs at a speed of over 500 km/h, and had a range of over 1,700 km.
Along with the B-26 Marauder, development began on another twin-engine medium bomber: the North American B-25 Mitchell. A pre-production series became operational at the end of 1941. In 1942, the sixteen planes that carried out the raid on Tokyo in response to the Japanese attack on Pearl Harbor were prepared. Nearly 11,000 B-25s were produced by the end of the war. The C version had two 1,700-horsepower Wright R2600 engines, 12 .50-caliber machine guns, and could carry 1,350 kg of bombs at a speed of 430 km/h with a range of more than 2,000 km. The B-25 Mitchell was also used for naval patrol and reconnaissance. Over 1,000 B-25 Mitchells were specially equipped for land or naval machine gunnery, featuring additional machine guns and a front-mounted 75 mm cannon.
The Boeing B-17 bomber was joined by the Consolidated B-24 Liberator, which was designed in 1939 and entered service in 1940. However, it did not enter mass production until January 1942, with nearly 2,700 Model Cs produced. The B-24 was one of the most historic heavy bombers of World War II, with more than 18,000 produced in all versions. Larger and faster than the B-17, the B-24 was powered by four Pratt & Whitney R-1830 engines, each rated at 1,200 horsepower. Armed with ten .50-caliber (12.7-mm) machine guns, the B-24 could carry a maximum load of 5,000 pounds of bombs on long-range missions. Nearly 20,000 of these robust aircraft were produced, capable of flying at a cruising speed of 350 km/h even with serious damage. The VLR Liberator version was equipped with additional fuel tanks, an AVS Mark II radar, and two powerful light projectors mounted under the wings. It made a significant contribution to convoy escorting and hunting German submarines in the Atlantic, both day and night.
Lastly, the B-29 Superfortress, a strategic heavy bomber, was designed in 1942 and entered service in June 1944. Powered by four Wright R3350 radial engines with over 2,000 horsepower each, it could fly over 12 kilometers at speeds over 600 kilometers per hour, with a maximum range of over 8,000 kilometers, depending on the bomb load, which could reach 9,000 kilograms. It was the first aircraft to be fully pressurized, equipped with a centralized CFCS fire control system, and later, an APG-15 radar system to handle its twelve Browning .30-caliber machine guns. Nearly 4,000 were produced. It was a very complex machine weighing over 60 tons at full takeoff. The engines caused wear and failure problems and were the most expensive design of the war; one plane cost about $650,000 at the time.
During the war, the Navy Air Force developed the Grumman F6F Hellcat heavy fighter to replace the earlier Wildcat design. The Hellcat became the U.S. Navy's flagship fighter during World War II, with more than 12,000 produced. Powered by a Pratt & Whitney R2800 radial engine capable of producing 2,000 horsepower, it outperformed the Japanese Zeros despite having over 100 kg of armor installed to protect the cockpit and engine oil circuit. The Hellcat was armed with six Browning .50 (12.7 mm) machine guns and could reach speeds of over 600 km/h with a range of 1,500 km.
In 1942, the Curtiss SB2C dive bomber entered service. Due to a series of improvements and fine-tuning, it would not be present on aircraft carriers until 1944. Also in 1942, the Chance Vought F4U Corsair fighter entered service. With its powerful Pratt & Whitney R2800 radial engine, the F4U proved superior to the P-51 Mustang and the Grumman Hellcat.
In summary, the U.S. Air Force began the war with just under 1,000 aircraft, but by mid-1945, it employed nearly 2,500,000 men and had approximately 80,000 active aircraft on various fronts.
Bibliography :
Pratt & Whitney website engine charts
Jane's 20th Century American Fighting Aircraft by Michael Taylor
THE UNITED STATES NAVY.
Following World War I, the 1922 Washington Disarmament Conference established principles and limits for constructing large naval units and aircraft carriers. The proportions agreed upon by the United States, Great Britain, and Japan prompted the United States to disarm some of its battleships and convert two of its battlecruisers under construction into aircraft carriers: the Lexington and the Saratoga. In 1930, these same nations agreed to further restrictions that halted experimentation and, consequently, the production of new ship models. In 1933, the U.S. naval adjustment program received a major boost when Congress authorized the construction of 1,325,000 tons of warships, including two additional aircraft carriers, as well as cruisers, destroyers, and submarines.
Following the outbreak of war in Europe and President Roosevelt's declaration of a limited state of emergency in the United States, the largest naval expansion in the history of the U.S. Navy began in June 1940, especially with the Two Ocean Navy Bill in July 1940. In the summer of 1940, England "granted" the United States a number of naval bases for 99 years in exchange for 50 old destroyers to be used in anti-submarine patrols. These bases were located in the North Atlantic, greatly expanding America's naval borders. These bases housed ships, naval aircraft, seaplanes, and support forces that escorted convoys carrying raw materials and equipment to England across the North Atlantic.
Immediately after the signing of the Two Ocean Protection Act in November 1939, construction of factories to produce raw materials for warships and merchant ships began and expanded significantly. Production capacities increased rapidly: many factories that produced non-essential materials were converted to support the war effort. Often, a factory would go from laying the foundation stone to delivering the first piece of ordered equipment in eight or nine months.
At the same time, several ship models were standardized. Consider the Liberty-class transport ships, for example, which provided logistics and supplies to forces fighting on two oceans. Just over 2,700 were built and could reach speeds of up to 11 knots.
The twin-deck model carried material and equipment. Other models were produced to carry tanks (up to 440), aircraft, or to serve as specialized vessels, such as tankers, hospitals, prisoner transports, and animal transports. Speaking of animals, many horses and especially mules were sent to Europe, especially to the Apennines of Italy. In the fall and winter, the mountain roads became muddy swamps from heavy tank and armored traffic, and only mules could extricate themselves from the mud to carry supplies to the front.
Between 1941 and 1945, more than 29 million tons of standard tonnage of Liberty-class ships were produced. The average cost of a Liberty ship was about $1,800,000. In comparison to the values of the time, this was equivalent to three German U-boats ($595,000 each) or eight B-17s ($240,000 each).
Of the 2,711 Liberty ships built and launched, the first of which was the SS Patrick Henry on September 27, 1941, one could be built in 70 days. Only 200 were sunk by the Germans or in accidents. The Liberty's shortcomings were due in part to the speed of construction; sometimes, the welds were imperfect, creating structural hazards when the ship was fully loaded or in rough seas. The design was also unstable when the ship was unloaded.
The construction of aircraft carriers represented another spectacular phase of the shipbuilding program. After the Japanese attack on Pearl Harbor on December 7, 1941, the United States adopted the strategy of front-line aircraft carriers instead of battleships. They began rearming both the naval and aircraft forces at the most critical point. By fall 1942, only the Saratoga, Enterprise, and Ranger carriers remained in service. By the end of 1943, there were more than 50 operational aircraft carriers, including the large front-line Essex and Independence classes, as well as escort carriers converted from light cruisers or merchant ships. Many of these were sent to Britain for anti-submarine service.
The naval force expanded to include heavy cruisers of the Baltimore and Alaska classes, light cruisers of the Brooklyn and Cleveland classes, destroyers of the Fletcher class—whose production increased from three ships every two months in 1941 to 11 ships per month in 1943—battleships South Dakota, Indiana, and Massachusetts, and heavy ships Iowa, New Jersey, and Wisconsin.
As the number of aircraft carriers increased, so did the Navy's air force at sea.
At the start of the war, the 1,200-horsepower Grumman Wildcat fighter was in service, with nearly 8,000 produced.
Over the course of the war, the following aircraft entered service:
- the Vought Corsair, equipped with a 2,000-plus-horsepower engine, in June 1942; and - the Grumman Hellcat, equipped with a 2,000 hp radial engine, in September 1943; it was produced in about 12,000 units.
- the Grumman Hellcat, equipped with a 2,000-hp radial engine, entered service in September 1943 and was produced in about 12,000 units.
- The Grumman Tigercat, equipped with two radial engines of over 2,100 hp each, entered service in April 1944 and was produced in about 360 examples.
- The Grumman Bercat, developed from the Hellcat model and equipped with engines of over 2,000 hp, was produced in over 1,250 units.
- The Douglas Dauntless scout and dive bomber was equipped with a 1,200 hp engine, and it was produced in just under 6,000 units. It was later joined by the Curtiss Helldiver, which was equipped with a 1,700 hp engine, and it was produced in just over 7,100 units.
- The Grumman Avenger torpedo bomber, equipped with a 1,700 hp radial engine, was produced in nearly 10,000 units and was joined by the Douglas Devastator.
- The Consolidated Catalina, a scout and patrol aircraft powered by two 1,200 hp engines, was produced in about 4,000 units. After Pearl Harbor, it was joined by the Martin Mariner, a similar aircraft powered by two 1,700 hp radial engines, which was produced in over 1,280 units.
In addition to the ground-based aircraft, the Navy also used the four-engine Consolidated Liberator and the twin-engine Vega Ventura, as well as the Lockheed Hudson and Douglas Havoc bombers, which saw limited service. The North American Mitchell was used by Marine air squadrons.
Not to mention the countless support and supply ships and motor torpedo boats. In 1943 alone, 600 patrol boats were produced. Navy personnel increased from approximately 126,000 in September 1939 to 330,000 in December 1941, 1,260,000 in December 1942, 2,380,000 in December 1943, and 3,220,000 in December 1944.
Just as the Army had its Engineer Corps, the Navy had its Seabees. They landed with the first wave, bringing in equipment and setting up temporary bases. Inland, they moved pontoons, repaired vehicles, loaded and unloaded ships, and performed any necessary construction work. By 1944, 240,000 Seabees were serving, both at home and overseas.
The Marine Corps deserves a separate discussion. Its origin dates back to November 10, 1775. In 1939, it consisted of 19,500 men, including officers. By 1945, the Corps had grown to include 478,000 men and women. The Marine Corps Air Force consisted of six full divisions and approximately 118,000 enlisted men and officers. Officers were trained at the Marine Corps School in Quantico, Virginia. These intensive training programs included advanced studies at the newly established Command and Staff School, which instructed officers in the administrative, personnel, and political aspects of their profession within Marine battalions, regiments, and divisions.
Bibliography:
Liberty Ship, the Ugly Duckling of World War II by John G. Bunker
United States Naval Aircraft since 1911 by Gordon Swanborough
Report of the Supreme American Command - Biennial Report for the Period July 1, 1939 to June 30, 1941.