The Curtiss SB2C Helldiver was a dive bomber developed by Curtiss-Wright during World War II. Nicknames for the aircraft included "Big-Tailed Beast" or just "Beast",O'Rourke, G.G, CAPT USN. "Of Hosenoses, Stoofs, and Lefthanded Spads." United States Naval Institute Proceedings, July 1968.Runyan February 1945, p. 132. "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.Shettle 2001, p. 29.
The Helldiver was developed during the late 1930s and early 1940s for the United States Navy (USN) to serve as a carrier-based bomber to supplement and replace the Douglas SBD Dauntless. First flown on 18 December 1940, the XSB2C-1 prototype initially demonstrated poor handling characteristics and other issues; late modifications caused lengthy delays to production and deployment, to the extent that the aircraft was investigated by the Truman Committee, which produced a scathing report. This negative coverage contributed to the decline of Curtiss as a company, and delayed the type's entry to service, despite the urgency associated with the outbreak of the Pacific War, until December 1942. In late 1943, a land-based variant, designated as the A-25 Shrike, became available; however, by this point, most Allied air forces had abandoned dedicated dive bombers. Accordingly, the majority of A-25s delivered to the United States Army Air Forces (USAAF) were promptly transferred to the United States Marine Corps (USMC), which used the type only in one-side campaign and non-combat roles. The British Royal Navy and the Royal Australian Air Force both cancelled substantial orders for the type,Wilson 1994, p. 85. retaining only a few aircraft for research purposes.
In service, the type was not typically appreciated by either pilots or senior USN officials.Ethell 1995, p. 221. Nevertheless, the Helldiver was faster than the Dauntless, and by the end of World War II, the Helldiver had become the primary dive bomber and attack aircraft on USN carriers.Ethell 1995, p. 221. As a result, several major battles fought during the latter part of the conflict had Helldivers present, including the Battle of the Philippine Sea, the Battle of Leyte Gulf, the Battle of Iwo Jima, and the Battle of Okinawa. The type was only briefly used during the early years of the Cold War, but did see further combat with other nations, such as with the Royal Hellenic Air Force during the Greek Civil War and the French Navy during the First Indochina War. Military use of the Helldiver ceased in the late 1950s, the dive bomber role having been largely rendered obsolete by the advent of air-to-ground rockets. Several Helldivers have been preserved into the twenty-first century.
Design and development The origins of the Helldiver can be traced back to 1938 and the issuing of a specification by the USN, seeking a replacement for the Douglas SBD Dauntless. In comparison to the Dauntless, the Helldiver was a much larger aircraft, able to operate from the latest aircraft carriers and carry a considerable array of armament. Despite this, it was necessary for it to be an exceptionally short airplane due to the USN also requiring two aircraft to fit onto an Essex-class carrier's elevators. The USN's requirements led to an aircraft 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 "multirole" aircraft into the design.Winchester 2004, p. 63.
The resulting aircraft possessed a relatively stubby and squat appearance, featuring a barrel-like forward fuselage with a deep belly that swept upwards towards the rear.Runyan February 1945, pp. 132-133. The wing, which was fitted with automatic slots, featured a straight leading edge and a forward-swept trailing edge; it could be folded for more compact stowage onboard ship. The wing and the tail-unit were unusually close-coupled; the tail unit featured a backswept leading edge and rounded tips. Both the fin and the rudder were relatively large, however, the tail unit was relatively short, which negatively impacted its directional authority. To enable it to better perform its core mission as a dive bomber, it was equipped with dive brakes that gave the pilot better control during descent as well as preventing the aircraft from attaining excessively high speed. Armor was present to protect both the pilot and tail gunner.Runyan February 1945, p. 133. It featured an internal bomb bay that reduced drag when carrying heavy ordnance, which was a first for an American dive bomber.Runyan February 1945, pp. 133, 205-206.
Early on, the type suffered from development issues, some of which were related to its Wright R-2600-20 Twin Cyclone radial 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 XSB2C-1 to the MIT wind tunnel. Professor of Aeronautical Engineering Otto C. Koppen, in reference to the controllability issues with the compact vertical tail, was quoted as saying: "if they build more than one of these, they are crazy".Abzug and Larrabee 1997, p. 92.
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 suffered from frequent maintenance problems.Tillman 1997, p. 61. 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.
On 18 December 1940, the XSB2C-1 prototype performed its maiden flight.Bowers 1979, p. 424. It crashed on 8 February 1941 when its engine failed on approach, after which Curtiss was instructed to rebuild it. During this reconstruction, the fuselage was lengthened, an enlarged tail unit was fitted, and an autopilot was fitted to address the aircraft's poor stability. On 20 October 1941, the revised prototype flew once more; however, it was destroyed after a wing failure occurred during diving tests on 21 December 1941.Donald 1995, pp. 76–77.Bowers 1979, pp. 424–425. Accordingly, the prototype could never be used in service trials.
On 29 November 1940, large-scale production of the type was ordered, however, it was specified that a large number of modifications be implemented for the production model. These included increased fin and rudder area, expanded fuel capacity, the adoption of self-sealing fuel tanks, and the fixed armament was doubled to four 0.50 in (12.7 mm) machine guns in the wings, compared with the prototype's two cowling guns. Accordingly, the SB2C-1 was built with larger fuel tanks, considerably improving its range. However, the 880 changes demanded by the USN and modification of the aircraft to better suit its combat role resulted in a 42 percent weight increase, which in turn impacted its performance.
In June 1942, the first production Helldiver flew for the first time. However, the long term resolution to several of the aircraft's performance issues did not arrive until 1944 with the introduction of the SB2C-3. This improved model was powered by the R-2600-20 Twin Cyclone engine, capable of producing up to , which drove a new Curtiss-developed four-bladed propeller.
The program suffered from numerous delays, to the extent that the Grumman TBF Avenger entered service before the Helldiver, despite work on the Avenger having begun development two years later. Nevertheless, production tempo accelerated with production at Columbus, Ohio, and two Canadian factories: Fairchild Aircraft Ltd. (Canada), which produced 300 (under the designations XSBF-l, SBF-l, SBF-3, and SBF-4E), and Canadian Car and Foundry, which built 894 (designated SBW-l, SBW-3, SBW-4, SBW-4E, and SBW-5), 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.Taylor 1969, p. 480.
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 aircraft being built. Accordingly, the first deployment model was the SB2C-1C.Goebel, Greg. Vector site, 1 November 2010. 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.Winchester 2004, p. 62. In 1943, the air commander of the Atlantic Fleet stated that: "due to continued malfunctioning, structural failures and other operational difficulties which affect use of armament and safety in flight, SB2C airplanes were considered entirely unsuitable for assignment to combatant carriers at this time".
The Helldiver participated in several major battles, including the Battle of the Philippine Sea (over the Marianas), the Battle of Leyte Gulf (near the Philippines), the Battle of Iwo Jima, and the Battle of Okinawa. Amongst other milestones, the type was credited with being partially responsible for the sinking of the Japanese battleships and sister ship , although other aircraft, such as the Grumman TBF Avenger, have been recognised as having likely achieved more damage to these vessels. During the Battle of the Philippine Sea, 45 Helldivers, most of which had been launched from extreme range, were lost after they ran out of fuel while attempting to return to their carriers; only five aircraft of the 51 Helldivers dispatched on this attack were able to successfully return.Runyan February 1945, p. 206.
In the closing months of the conflict, Helldivers were also employed in the 1945 attacks on the Ryukyu Islands and the Japanese home island of Honshū in tactical attacks on airfields, communications, and shipping. The type was extensively used on patrols during the period between the dropping of the atomic bombs and the official Japanese surrender and in the immediate preoccupation 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, the U.S. Navy's Grumman F6F Hellcat and Vought F4U Corsair fighters were found to be 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.