The Curtiss SB2C Helldiver was the main US Navy dive bomber during the last two years of the Second World War. Although it was a significant improvement over the Douglas SBD Dauntless, offering a big increase in speed, it arrived too late to take part in the major carrier battles of the war, and was not popular with its pilots, earning the nicknames “the beast” and “Son-of-a-Bitch 2nd Class”.
Many of the aircraft’s problems were imposed by the Navy specifications, issued in August 1938. These called for an aircraft capable of carrying a 1000lb bomb in an internal bomb bay, with a higher fuel capacity (and range) than the SBD, powered by the Wright R-2600 Cyclone 14 engine, itself then under development. The main restriction on the designers was size – two of the new aircraft had to fit on a standard aircraft carrier elevator with a foot clearance all around. These elevators were 40 feet wide by 48 feet long. The production SB2C would be 36 feet 9 inches long, and 49 feet 9 inches wide, reduced to around 20 feet with the wings folded. The prototype XSB2C-1 was significantly shorter.
Wind tunnel tests on a scale model, carried out early in 1940, suggested that the new aircraft would have an unacceptable high stall speed, giving it a high landing speed, not acceptable on carrier aircraft. The tests also suggested that the new aircraft would have poor handling characteristics. Despite these problems an order for 370 aircraft was placed in November 1940. Three weeks later, on 13 December 1940, the first prototype XSB2C Helldiver was ready.
The development process was slow. The first flight came on 18 December, and revealed poor low speed stability, with some problems at high speed. The Wright Cyclone also needed much more work, and on 9 February 1941 failed just before landing. The prototype was out of action until May. It then flew again for a week, before a landing gear collapse took it out of use until June.
In August the prototype was taken away for major modifications, which saw it stretched by a foot. After more test flights in September the tail was enlarged, and tests resumed in late October. On 21 December, during a high-stress dive test, the right wing and tail failed while the aircraft was recovering from the dive. The test pilot, Baron T. Hulse, survived, but the aircraft was written off.
The problems with the prototype were matched by problems with production. The first production aircraft was not ready until June 1942, six months later than planed. It suffered from a common failing in American aircraft design in the early years of the Second World War. The prototype had been built without many essential features, including self-sealing fuel tanks or armour. Worse, the prototype Helldiver had used very light weight alloys, replaced in the production aircraft by heavier aluminium. The empty weight of the aircraft rose from 7,122lbs to 10,144lbs. Top speed dropped, landing speed rose, range was reduced and rate of climb slowed.
Despite all of these problems, production continued. So many changes needed to be made to the basic model that a second factory had to be set up to modify new aircraft, working in parallel to the main factory until November 1943, when the main production line finally caught up with all the changes on aircraft number 601. By this point production had moved onto the SB2C-1C (starting with the 201st aircraft), which featured every change made on earlier aircraft, as well as replacing the two .50 calibre machine guns in each wing with one 20mm cannon. 778 dash-1Cs were built, becoming the main operational model by the spring of 1944, when the Helldiver began to replace the Dauntless in earnest.
The majority of problems with the Helldiver were cured during production of the SB2C-3, which began in the spring of 1944. The most important change made was the use of a more powerful Wright R-2600-20 engine, capable of providing 1,900hp. With the new engine top speed increased by 13mph, up to a creditable 294 mph. The increase in power also improved the aircraft’s handling. Another problem that had plagued the Helldiver was its high speed in the dive. In a fast dive the aircraft approached the speed at which compressibility caused tail buffeting and lack of lift. Once it was realised what the problem was, the dash-three was equipped with perforated dive brakes, which solved the problem. Curtiss produced 1,112 of the dash-three, while the Canadian Car and Foundry (CC&F) produced 413 as the SBW-3 and Fairchild of Canada produced 150 as the SBF-3.
The most numerous version of the Helldiver was the SB2C-4, of which 2,045 were built by Curtiss and 100 by Fairchild. The dash-four featured every change made during the production of the dash-three. It also carried eight zero-length rocket launchers under the wings. By now the much maligned Helldiver had matured into an impressive aircraft, with performance as good as any of its competitors.
One more production variant would appear, the SB2C-5, but this version appeared too late to see service in large numbers. Production began in February 1945, and by the time it stopped at the end of the war 970 had been built by Curtiss, and 85 by CC&F (as the SBW-5). The main change made to the dash-five was in fuel capacity, increased by 35 gallons. The end of the war also ended work on the XSB2C-6, which was powered by a 2,100hp R-2600-22, resulting in another increase in top speed, but none were ordered.
Carrier tests began in November 1942, when a number of Helldivers were issued to the USS Essex. However, before serious work could begin the Essex had to return to the combat area, leaving its Helldivers behind. The first sea tests took part on the Yorktown in May 1943. They did not go well. The SB2C-1 was not really ready for service. Its poor low speed handling caused a series of crashes, and even the aircraft that did not crash were often out of commission. The land gear had a tendency to collapse under the weight of the aircraft. However, one should not overemphasis the seriousness of these problems. The F4U Corsair also suffered from serious problems when first tested on carriers, and during its carrier the majority of Corsairs lost were lost in accidents.
The Helldiver finally entered active service in October 1943, with VB-17 on the USS Bunker Hill. The aircraft saw action on 11 November, taking part in a raid on Rabaul. More significant service soon followed, as the Helldivers of the Bunker Hill helped support the invasion of Tarawa. The Helldiver now proved itself to be a capable combat aircraft. In the sustained operations over Tarawa it proved itself to be a reliable accurate dive bomber (at least as long as it didn’t crash on landing).
The Helldiver began to replace the SBD Dauntless during the first half of 1944. At the start of February the Bunker Hillwas still the only carrier to carry the new aircraft, by June it equipped five squadrons on five carriers. The type played an important role in the Battle of the Philippine Sea, although 51 aircraft were lost, most while returning to their carriers. The lost aircraft were replaced by the superior dash-three in time for the Battle of Leyte Gulf, and the Beast began to loose its bad reputation. A sign of the improving performance of the Helldiver was its adoption as the standard Navy dive bomber after the war. However, by this point the dive bomber was becoming less important as a type. Standard naval fighters armed with rockets were just as effective an anti-shipping weapon, and the Corsair could carry the same bomb load as the Helldiver. The Helldiver was responsible for sinking a large number of Japanese ships, but because of its late entry into combat was operating in an increasingly safe environment as the quality of Japanese fighter opposition declined.
Engine: Wright R-2600-20 Cyclone
Horsepower: 1,900 at take-off
Span: 49 feet 9 inches
Length: 36 feet 9 inches
Maximum Speed: 294 mph at 12,400 feet
Range: 1,200 miles
Ceiling: 25,000 feet
Armament: Two 20mm cannon, one in each wing, two .30 calibre machine guns in the rear cockpit
Bomb load: 2,000lbs maximum, part in bomb bay and part under wings.