The Curtiss XBT2C was a prototype two-seat, single-engined dive/torpedo bomber developed during World War II for the United States Navy. Derived from the Curtiss SB2C Helldiver dive bomber, it was an unsuccessful competitor to meet a 1945 Navy specification for an aircraft to combine the roles that previously required separate types. Unlike the other competitors, the XBT2C was designed to accommodate a radar operator.
Design and development
In the 1930s and early 1940s, the Navy divided carrier-borne bombers into two types: the torpedo bomber and the dive bomber, each with crews of two or three men. Wartime experience showed that pilots could aim bombs and torpedoes without assistance from other crewmembers as well as navigate with the aid of radio beacons and the development of more powerful engines meant that faster aircraft no longer needed a rear gunner for self-defense. Furthermore, the consolidation of the two types of bombers greatly increased the flexibility of a carrier's air group and allowed the number of fighters in an air group to be increased.
Curtiss had been proposing changes to improve the Curtiss SB2C Helldiver two-seat dive bomber almost since the aircraft had entered production in 1942, but the Navy rejected those that might adversely impact production. The company submitted a proposal in August 1944 for a redesigned single-seat dive/torpedo bomber version of the Helldiver with the more powerful Wright R-3350 Duplex-Cyclone radial engine to meet a competition for this class of aircraft, but this was rejected because it was not deemed a significant enough improvement to warrant interrupting production. Six months later Curtiss submitted a reworked proposal that included a bubble canopy, a streamlined fuselage and empennage, and carried a second crew member in the rear fuselage to operate the radar, which was mounted in a pod under the starboard wing. To speed development and ease production, the XBT2C retained much of the Helldiver's wing and fuselage structure.
The Navy issued Detail Specification SD-394A on 29 January 1945 for the XBT2C-1 that matching Curtiss' proposal and followed it up with a contract for ten prototypes the following month. Only nine aircraft were ultimately completed as the engine cowling, wings and empennage of the tenth aircraft was fitted to one of the Curtiss XSB2C-6 prototypes instead. Sharing about half of its parts with the Helldiver, construction of the first aircraft was relatively quick and it made its first flight on 7 August.
Description
Like the Helldiver the XBT2C was a low-wing monoplane with retractable conventional landing gear, although its more powerful R-3350 engine required a larger propeller. Unable to alter the wheel wells that the aircraft inherited from the Helldiver, Curtiss used a telescoping oleo strut mechanism to provide the necessary additional length of the landing gear. The extra height of the landing gear would have increased the height of the aircraft so that it could no longer fit inside the hangars of the s with its wings folded until most of the wing tip outside the aileron was removed to reduce the height to . For comparison purposes, the Navy demanded a engine cooling fan, much like those used by various Japanese aircraft, be installed. Trials showed that the fan eliminated the need for the cowl flaps traditionally needed to cool the engine and its accessories.
The XBTC used the same fuel tanks as the Helldiver with the addition of tanks. This increased the aircraft's total internal fuel supply to divided between a fuselage tank and interconnected wing tanks of and 45-US-gallon capacity. All of the tanks were self-sealing. The XBTC could carry an additional of fuel in three drop tanks. One could be fitted to the center shackle in the bomb bay and the others positioned on the main wing hardpoints.