The Curtiss XBTC was a single seat torpedo and dive bomber that entered development in 1942 but didn’t make its maiden flight until 1945, and that lost out to more modern Douglas and Martin designs.
In January 1942 the US Navy’s Bureau of Aeronautics issued specifications for a single seat single engine carrier aircraft that would combine the roles of dive bomber and torpedo bomber in a single aircraft. This was to be powered by the R-3360 engine and armed with four 20mm cannon. The task of developing the new aircraft was given to Curtiss-Wright’s Columbus division.
In June 1942 Curtiss submitted a proposal to produce two versions, one using the R-3350 engine and the other with the new Pratt & Whitney R-4360 engine. Late in the month the Navy issued letters of intent for four prototypes, two XBTC-1s powered by the R-3350 and two XBTC-2s powered by the 3,000hp Pratt & Whitney R-4360 Wasp Major. The two types would be very similar, but the XBTC-2 would have two feet longer wings and use contra rotating propellers to take advantage of the extra engine power. The new aircraft would have an internal bomb bay that could carry a single bomb or torpedo or could carry bombs and a torpedo externally.
Problems with other Curtiss designs now conspired against the XBTC. The SB2C-1 Helldiver was entering into production, and was proving to be troublesome. The SO3C observation seaplane was proving to be a disappointment, so Curtiss was ordered to give the single seat XSC-1 a higher priority. Wright were also struggling with the R-3350 engine. As a result on 31 December 1942 Curtiss was given a contract to produce the two XBTC-2 prototypes (serial numbers 31401 and 31402), but with a low priority, while the XBTC-1 was cancelled.
The XBTC was produced with two different wings. The original plan had been to give it full span Duplex flaps. However early wing tunnel tests revealed problems with this design, so a less complex alternative was also produced. Both had the same inner section, with tapering leading and trailing edges. The ‘Model A’ had a straight leading edge and tapered trailing edge, wile the ‘Model B’ had a tapered leading edge and straight trailing edge, and the full span flaps.
The first XBTC-2 with the Model A wing, made its maiden flight in January 1945.
The slow progress now doomed the project. Douglas only came up with the basic design for the XBT2D (the early designation for the AD Skyraider) in July 1944 when they were informed that their BTD-1 was to be cancelled, but the prototype made its maiden flight on 18 March 1945, and a contract for 548 production aircraft was signed on 5 May 1945. The Martin XBTM-1 (later AM Mauler) made its maiden flight on 26 August 1944 and an order for 750 aircraft was placed on 15 January 1945. Both of these aircraft were considered to be more advanced than the Curtiss design, although work on it continued to test out the contra-rotating propellers and the full span flaps.
The second prototype was completed with the Model B wing, and the first prototype had its Model B wing installed during the year. The original Curtiss electric contra-prop failed, and had to be replaced by a new Aeroproducts design. The contra rotating drive gears also caused problems that grounded the aircraft for some time. However both prototypes were delivered to the Naval Air Test Centre at Patuxent River, Maryland, in July 1946, where they served with the NATC’s Flight Test and Service Test division. However both aircraft were soon lost – the first prototype was lost while being trnasfered to the Naval Air Material Centre in Philadelphia in August 1947 and the second was lost in a crash in February 1947.
Curtiss also developed the XBT2C, which was a modified version of the SB2C Helldiver. This proved to be a rather easier aircraft to develop, but also failed to enter production, once again losing out to the Douglas and Martin designs.
Engine: Pratt & Whitney XR-4360-8A Wasp Major
Length: 38ft 7in
Height: 12ft 11in
Empty weight: 13,410lb
Maximum take-off weight: 21,600lb with one Mk.13-2 torpedo
Max speed: 370mph at 16,000ft
Climb Rate: 2,250ft/ min
Service ceiling: 26,200ft
Range: 1,800 miles at 188mph
Armament: Four 20mm cannon
Bomb load: One 1,600lb torpedo internally or one Mk 13-2 torpedo under and two 500lb bombs under fuselage