In 1930, the Naval Affairs Committee proposed an amendment to the discussion, recommending the construction of one more small aircraft carrier and two medium aircraft carriers of increased tonnage in the future. Pen ~ fun ~ Ge www.biquge.info small aircraft carriers can be used to follow the battleship, while medium aircraft carriers can be used as a strike force independently, which can not only meet the tactical needs of the navy, but also make full use of the remaining tonnage. The medium-sized design eventually led to the two Yorktown-class aircraft carriers, as well as the USS Vespa, which was miniaturized. [6]

The controversy over the medium-sized design is similar to that of the Raider, in terms of speed, defense and carrier-based aircraft. In terms of speed, with the exception of Lieutenant Colonel Kelly Turner, who represented the Aviation Department, who accepted a lower speed in exchange for space in other facilities, the other departments generally agreed to increase the speed from 29 knots to 32.5 knots. In terms of defense, the focus is on reducing the chance of flight deck being paralyzed by air strikes and overall defensive armor. In response to the first problem, the Aviation Department has proposed to build a double-deck flight deck, install hangar catapults and add lifting platforms to improve the efficiency of aircraft lifting, but these equipment, together with armor, etc., are not affordable by the medium design tonnage. In terms of armor, the Yorktown-class was positioned to defend against the 6-inch guns, bomb-drops, and torpedo attacks of light cruisers, but had to compromise due to tonnage limitations. Finally, in terms of carrier-based aircraft, the Aviation Department was working out a new air regiment composition, which should consist of 18 aircraft in each of the four squadrons, a total of 72 aircraft, and then a number of substitutes. However, due to different calculation methods, the ministry estimates that the number of aircraft on the new ship can exceed 90. Based on the experience of the Lexington class, the Panel also considered that the island was not detrimental to flight operations, and therefore decided to add an island to the new ship to effectively remove the boiler exhaust gases. [7]

In early 1932, the Panel finally selected a 20,000-ton displacement, 770-foot length, 80.3-foot width, 120,000 shaft horsepower, 32.5 knots maximum speed, and 90 carrier-based aircraft. However, citing the economic depression, Congress did not allocate funds for the construction of a new aircraft carrier, which further delayed the design. During this period, the Secretary of the Navy asked the War Department to study a 27,000-ton plan for the installation of 8-inch guns, but it was ultimately aborted.

Two Yorktown-class ships were launched in 1936 and commissioned in 1937 and 1938 respectively. At that time, the main features of the hull were as follows:[8]

After the outbreak of World War II, the United States was no longer bound by disarmament treaties. The Navy could rush to build one more aircraft carrier to meet the needs of the war. Due to the tight schedule, the Naval Affairs Committee had no choice but to propose a continuation of the Yorktown-class design, with a number of improvements, notably staggered configuration of the new ship's boilers and engines to reduce risk. However, due to too many changes, the new ship Hornet could only build a new island and extend the bow, and the problem of the power system was not solved. At the Battle of Midway and the Battle of the Santa Cruz Islands, both the Yorktown and the Hornet were damaged by a torpedo attack and could not leave the battlefield and sank. [7]

At the time of the design of the Yorktown class, radar technology was not yet mature. In 1937, the Navy developed the first ship search radar, which was named CXAM in 1940 and installed on many ships. The Yorktown was fitted with a CXAM radar in 1940, while the Enterprise was fitted with a CXAM-1 radar in 1941. With an accuracy of 300 yards and a resolution of 400 yards, CXAM can generally detect battleships within 16 feet, destroyers within 12 kilometers, PBY seaplanes at 10,000 feet high within 70 kilometers, or fighter jets at the same altitude within 50 kilometers. The accuracy of the CXAM-1 has been improved to 200 yards. Due to the bulky CXAM radar, the Hornet was commissioned in 1941 with a new type of SC radar, but the search range was greatly reduced, and it could only detect battleships within 10 km, destroyers within 3 km, fighters up to 30 km, and bombers up to 25 km. As a result, the Navy soon dismantled the CXAM radar of the battleship USS California, which was sunk in Pearl Harbor, and installed it on the USS Hornet, leaving the SC radar as a backup. At the same time, the Navy has installed a new YE return device for the Hornet, which cooperates with two radars to guide the carrier-based aircraft to return to landing. [9]

Both the Yorktown and the Hornet sank in 1942 without further radar and electronic systems. In the second half of 1942, the Enterprise installed an SG radar for horizontal search, with an accuracy of 200 yards and a resolution of 400 yards, capable of detecting bombers at a low altitude of 500 feet within 15 feet, battleships within 22 kilometers, and destroyers within 15 kilometers. The Enterprise was also equipped with the SC-1 radar, which doubled its search range and increased its accuracy to 100 yards with a resolution of 500 yards. When the Enterprise returned home in 1943 for overhaul, the CXAM-1 radar was replaced with a new SK radar, and the search range increased to 10,000 feet within 100 feet of the medium-sized bomber, with an accuracy of 100 yards and a resolution of 900 yards. The Enterprise was also equipped with an SM radar to search for aircraft at a distance of 50 feet at an altitude of 10,000 feet and battleships within 25 kilometers with an accuracy of 500 to 200 yards and a resolution of 200 yards. The SM radar is the first batch of fighter deployment radars of the US military, and it is only at this time that US aircraft carriers can effectively deploy fighter jets to intercept enemy aircraft. Together with the addition of the YG Return to Home device and the IFF Identification Friend or Foe System, the Enterprise's radar and electronics are comparable to those of the new Essex-class aircraft carriers commissioned in 1943. [10]

At the end of the war, the Enterprise changed the SC-1 radar to a new SR radar with an accuracy of 30 to 100 yards and a resolution of 500 yards, which could detect bombers flying at 10,000 feet within 110 feet, fighters at the same altitude within 75 kilometers, and bombers flying at 500 feet at 25 kilometers. At the same time, the company has a prototype of the combat command system, and in wartime, it will send TBM bombers carrying long-range radars to transmit its data back to the ship for processing and analysis. In 1945, the Enterprise also installed an initial electronic jamming system that could jam enemy radio signals. [10]

A recent photo of the Hornet's ship. No. 1 is the Mark4 fire control radar (FD fire control radar), and its base is the Mark37 fire control device. The Yorktown and Enterprise were initially equipped with only a Mark 33 fire control unit, which made it difficult to install auxiliary radars, and was later replaced by Mark 37. No. 2 is a YE return device, which sends a radio signal to friendly carrier-based aircraft to guide the return home. No. 3 is the SC radar. Originally, the SC radar was used to upgrade the CXAM and CXAM-1 radars, but its performance was not satisfactory. Soon after, the Hornet switched back to the CXAM radar.

Carrier-based aircraft and flight facilities

At the beginning of its service, the Yorktown class still carried pre-war aircraft models, including Grumman's F2F and F3F fighters, Martin's BM bombers (torpedo-dive) and Northrop's BT bombers (dive bombers). The Yorktown and Enterprise were replaced with F4F fighters in 1941 and SBD, TBD and TBF bombers in 1942. The late Hornet was replaced with an F4F in 1942 and began its service with SBC dive bombers and Brewsteraeronautical Corporation's SBN bombers. [11]

Due to the fact that the Navy did not have a complete radar system in early 1942, and the Navy inherited the pre-war attack-first tactics, the Yorktown class initially used bombers as the core of the aviation group. For example, in the Battle of Midway, the USS Yorktown, USS Enterprise, and USS Hornet carried 75, 79, and 79 aircraft, respectively, and the air regiments of the three ships were composed of one fighter squad (F4F), one torpedo bomber squadron (TBD), one dive bomber squadron (SBD), and one reconnaissance aircraft squadron (SBD). The three ships have 21 to 25 fighters, 37 to 38 dive bombers, and 13 to 15 torpedo bombers. After the Battle of Kuah began, the remaining USS Enterprise and HMS Hornet successively increased the number of fighters and reduced the number of torpedo bombers and dive bombers. In late 1943, the Enterprise was replaced with an F6F fighter, and by mid-1944, the Enterprise was a mix of F6F and F4U fighters, and replaced with an SB2C bomber. At this time, the Enterprise typically carried more than 34 fighters, 21 to 30 dive bombers, and 14 to 16 torpedo bombers. In 1945, the USS Enterprise was converted into a night combat aircraft carrier, and its air regiment was dedicated to the night and pre-dawn fighter alerts. The number of carrier-based aircraft dropped to 53 to 61, and all of them consisted of radar-mounted F6F and TBMs. [11]

The Yorktown-class hangar catapults, which had already been found to be inefficient before the war, were dismantled after the Battle of Midway in 1942. The Enterprise's bow landing facility was also dismantled later as it was rarely used. There were no significant changes to the other flight facilities.

Anti-aircraft artillery and fire control systems

The Yorktown-class 1.1-inch anti-aircraft gun and 0.5mm Browning machine gun had operational problems before they were built. In 1939, the Bureau of Naval Armament began to deal with the problem of the backwardness of the fleet's anti-aircraft guns, and in 1940 began to produce the Pofoss 40mm anti-aircraft gun and the Oligas 20mm anti-aircraft gun, replacing the 1.1-inch gun and the Browning machine gun, respectively. The Hornet, built in 1941, has replaced all 24 Browning with single 20mm anti-aircraft guns; The Yorktown was replaced on the east coast of the United States after Pearl Harbor and then rushed to the Pacific Ocean; As for the Enterprise, on the eve of the air raid on Tokyo, 32 single-mount 20-mm anti-aircraft cannons were installed at one time, making her anti-aircraft firepower superior to that of ships of the same class. As for the Povers guns, they were installed on the Enterprise and its escort ship South Dakota before the Battle of the Santa Cruz Islands, which was one of the reasons for the Enterprise's survival. After the Santa Cruz War, the Hornet sank, and the Enterprise was too busy with the war to repair. After 1943, the Navy took the opportunity of the Enterprise to return to China for overhaul and began to significantly install anti-aircraft guns. By 1945, the Enterprise's anti-aircraft armament had increased to 11 4-pack Pophards guns, 5 twin Povers guns, and 16 twin-pack 20 mm anti-aircraft guns. [11]

In terms of the launch control system, both the Yorktown and the Enterprise were equipped with two Mark 33s at the beginning of their service. Designed for the 5-inch/38-inch gun, the MARK33 is fully electrically operated compared to the previous generation of manually operated MARK19 and MARK28, which can measure the distance and altitude of the aircraft more effectively. Due to the late commissioning of the Hornet, the newer mark37 was installed, which is larger than the mark33 and can accommodate a larger computer to improve performance. What's more, the computer and support points of the MARK37 are located on the deck below the launch control unit, rather than inside the unit, so that there is ample room for the system to be upgraded and the new radar assist can be installed. [12]

Both the Mark 33 and Mark 37 can be fitted with auxiliary fire control radars. In 1942, the United States prepared to install the FD fire control radar (Mark 4) of the first generation of anti-aircraft and horizontal naval guns on the USS Yorktown and USS Enterprise, but the USS Yorktown was sunk in the Battle of Midway, and the USS Enterprise was later equipped with two to assist the Mark 33 to guide the firing of 5-inch guns. The Hornet was already installed during sea trials. FD radar can detect 5-inch shells within 12,000 yards, bombers within 40,000 yards, battleships within 30,000 yards, destroyers within 20,000 yards, and submarines surfaced within 12,000 yards with an accuracy of 40 yards and a resolution of 400 yards. In 1943, when the Enterprise returned to China for overhaul, the Mark33 system was upgraded to Mark37. When the Enterprise returned to China for repairs in 1945 due to the damage of the suicide plane, the FD radar was replaced with a new product Mark 12/22 fire control radar, but it had no effect on the duty of the Enterprise that was about to be decommissioned. [12]

Finally, the Yorktown-class anti-aircraft weapon also has another set of fire control devices. At first, the 1.1-inch anti-aircraft guns and Browning machine guns of the Yorktown-class triship could only be aimed at crosshairs and tracer rounds. In 1941, the three ships installed the Mark 44 fire control device, but in fact the device was only composed of optical sight glasses, and the anti-aircraft weapons were still all aimed by hand. By 1943, the Enterprise was fitted with a Mark51 fire control device, supplemented by a Mark14 sight. The latter consists of two gyroscopes, combined with simple computer calculations, to calculate the appropriate firing angle and distance for the Bofoss gun and the 20mm cannon respectively. [12]

(To be continued.) )