Curtiss SB2C Helldiver
The Curtiss SB2C Helldiver was a dive bomber developed by Curtiss-Wright during World War II. As a carrier-based bomber with the United States Navy, in Pacific theaters, it supplemented and replaced the Douglas SBD Dauntless. A few survivors are extant.
Initially poor handling characteristics and late modifications caused lengthy delays to production and deployment, to the extent that it was investigated by the Truman Committee, which turned in a scathing report. This contributed to the decline of Curtiss as a company. Neither pilots nor aircraft carrier skippers seemed to like it. Nevertheless, the Helldiver was faster than the Dauntless, and by the end of the Pacific War, the Helldiver had become the main dive bomber and attack aircraft on USN carriers.
By the time a land-based variant, known as the A-25 Shrike, became available in late 1943, the Western Allied air forces had abandoned dedicated dive-bombers. A majority of A-25s delivered to the US Army Air Forces were transferred to the US Marine Corps, which used the type only in one side campaign and non-combat roles. The British Royal Navy and the Royal Australian Air Force also cancelled substantial orders, retaining only a few aircraft for research purposes.
Nicknames for the aircraft included "Big-Tailed Beast" or just "Beast", "Two-Cee", and "Son-of-a-Bitch 2nd Class"; the latter nickname was derived from the name SB2C and the aircraft's reputation for having difficult handling characteristics.
Design and development
The Helldiver was developed to replace the Douglas SBD Dauntless. It was a much larger aircraft, able to operate from the latest aircraft carriers and carry a considerable array of armament. Despite this, the Navy also required two aircraft to fit onto an Essex-class carrier's elevators, requiring an exceptionally short airplane. It featured an internal bomb bay that reduced drag when carrying heavy ordnance. The Navy's requirements led to a plane with the contradictory requirements of being larger than any other carrier aircraft on the inside while being sharply size-restricted on the outside. Saddled with demanding requirements set forth by both the U.S. Marines and United States Army Air Forces, the manufacturer incorporated features of a "multi-role" aircraft into the design.The Model XSB2C-1 prototype initially suffered development issues connected to its Wright R-2600 Twin Cyclone engine and three-bladed propeller; further concerns included structural weaknesses, poor handling, directional instability, and bad stall characteristics. In 1939, a student took a model of the new Curtiss XSB2C-1 to the MIT wind tunnel. Professor of Aeronautical Engineering Otto C. Koppen was quoted as saying, "if they build more than one of these, they are crazy". He was referring to controllability issues with the small vertical tail.
The first prototype made its maiden flight on 18 December 1940. It crashed on 8 February 1941 when its engine failed on approach, but Curtiss was asked to rebuild it. The fuselage was lengthened and a larger tail was fitted, while an autopilot was fitted to help the poor stability. The revised prototype flew again on 20 October 1941, but was destroyed when its wing failed during diving tests on 21 December 1941.
Large-scale production had already been ordered on 29 November 1940, but a large number of modifications were specified for the production model. Fin and rudder area were increased, fuel capacity was increased, self-sealing fuel tanks were added, and the fixed armament was doubled to four 0.50 in machine guns in the wings, compared with the prototype's two cowling guns. The SB2C-1 was built with larger fuel tanks, improving its range considerably.
The program suffered so many delays that the Grumman TBF Avenger entered service before the Helldiver, even though the Avenger had begun its development two years later. Nevertheless, production tempo accelerated with production at Columbus, Ohio and two Canadian factories: Fairchild Aircraft Ltd., which produced 300, and Canadian Car and Foundry, which built 894, these models being respectively equivalent to their Curtiss-built counterparts. A total of 7,140 SB2Cs and equivalent models were produced in World War II.
Operational history
US Navy
The U.S. Navy would not accept the SB2C until 880 modifications to the design and the changes on the production line had been made, delaying the Curtiss Helldiver's combat debut until 11 November 1943 with squadron VB-17 on, when they attacked the Japanese-held port of Rabaul on the island of New Britain, north of Papua New Guinea. The first version of the SB2C-1 was kept stateside for training, its various development problems leading to only 200 being built. The first deployment model was the SB2C-1C. The SB2C-1 could deploy slats mechanically linked with landing gear actuators, that extended from the outer third of the wing leading edge to aid lateral control at low speeds. The early prognosis of the "Beast" was unfavourable; it was strongly disliked by aircrews due to its size, weight, and reduced range compared to the SBD it replaced.In the Battle of the Philippine Sea, 45 Helldivers, most of which had been launched from extreme range, were lost when they ran out of fuel while returning to their carriers.
Among its major faults, the Helldiver was underpowered, had a shorter range than the SBD, was equipped with an unreliable electrical system, and its manufacturing quality control was often poor. The Curtiss-Electric propeller and the complex hydraulic system had frequent maintenance problems. One of the faults of the aircraft throughout its operational life was poor longitudinal stability, resulting from a fuselage that was too short due to the necessity of fitting onto aircraft carrier elevators. The Helldiver's aileron response was also poor and handling suffered greatly under airspeed; since the speed of approach to land on a carrier was supposed to be, this proved problematic. The 880 changes demanded by the Navy and modification of the aircraft to its combat role resulted in a 42% weight increase, explaining much of the problem.
The solution to these problems began with the introduction of the SB2C-3 beginning in 1944, which used the R-2600-20 Twin Cyclone engine with and Curtiss' four-bladed propeller. This substantially solved the chronic lack of power that had plagued the aircraft.
The Helldivers would participate in battles over the Marianas, Philippines, Taiwan, Iwo Jima, and Okinawa. They were also used in the 1945 attacks on the Ryukyu Islands and the Japanese home island of Honshū in tactical attacks on airfields, communications and shipping. They were also used extensively in patrols during the period between the dropping of the atomic bombs and the official Japanese surrender, and in the immediate pre-occupation period.
An oddity of the SB2Cs with 1942 to 1943-style tricolor camouflage was that the undersides of the outer wing panels carried dark topside camouflage because the undersurfaces were visible from above when the wings were folded.
In operational experience, it was found that the U.S. Navy's Grumman F6F Hellcat and Vought F4U Corsair fighters were able to carry an equally heavy bomb load against ground targets and were vastly more capable of defending themselves against enemy fighters. The Helldiver, however, could still deliver ordnance with more precision against specific targets and its two-seat configuration permitted a second set of eyes. The Helldiver also had a significant advantage in range over a fighter while carrying a bombload, which is crucial in naval operations.
The advent of air-to-ground rockets ensured that the SB2C was the last purpose-built dive bomber produced. Rockets allowed precision attack against surface naval and land targets, while avoiding the stresses of near-vertical dives and the demanding performance requirements that they placed on dive bombers.
The SB2C remained in active postwar service in active duty US Navy squadrons until 1947 and in Naval Reserve aviation units until 1950. Surplus aircraft were sold to the naval air forces of France, Italy, Greece, Portugal, and Thailand. Greek SB2Cs served in combat in the Greek Civil War with additional machine guns mounted in wing pods. French SB2Cs flew in the First Indochina War from 1951 to 1954.
US Army and US Marine Corps service
Built at Curtiss' St. Louis plant, 900 aircraft were ordered by the USAAF under the designation A-25A Shrike. The first ten aircraft had folding wings, while the remainder of the production order omitted this feature. Many other changes distinguished the A-25A, including larger main wheels, a pneumatic tailwheel, ring and bead gunsight, longer exhaust stubs, and other Army-specified radio equipment. By late 1943, when the A-25A was being introduced, the USAAF no longer had a role for the dive bomber, as fighter aircraft such as the Republic P-47 Thunderbolt had shown their ability to carry out tactical air support missions with great success.The USAAF transferred 410 Helldivers to the US Marines. The A-standard 25As were converted to the USMC variant, SB2C-1A and one squadron, VMSB-151, based on Enjebi conducted bombing missions on bypassed Japanese strongpoints nearby. Otherwise, the SB2C-1A variant never saw combat, and was used primarily as a trainer and target tug.
Australian service
At an early stage of World War II, the Australian government noted that the Royal Australian Air Force lacked dedicated dive bombers and ordered 150 Curtiss Shrikes. These aircraft were paid for by the US Government as Lend Lease aid.By November 1943, when the first shipment of 10 Shrikes arrived in Australia, the RAAF had decided that dive bombing was an outmoded tactic. Vultee Vengeance dive bombers, which were already in service with the RAAF, were being replaced by light bombers. As a result, the order for the remaining 140 Shrikes was cancelled.
While the 10 aircraft received were taken on strength, with the RAAF serial prefix A69, only one of these Shrikes officially took to the air in RAAF service. A69-4 was assigned to No. 1 Air Performance Unit, for performance testing, between December 1943 and April 1944. The RAAF and US Fifth Air Force already operated a joint pool of aircraft types common to both services in the South West Pacific theatre and, by mid-January 1944, the other nine Shrikes had been transferred to USAAF units. A69-4 was also transferred to the USAAF in December 1944.