RB-66A

Douglas RB-66A Destroyer

     The Douglas B-66 Destroyer was originally envisaged as a replacement for the World War 2-era piston-engined Douglas B-26 Invader in the tactical bombing role for both day and night operations. On June 14, 1951, the USAF issued a formal requirement for a tactical bombing aircraft to meet this need. The initial requirement specifically asked for a reconnaissance vehicle, but in August the requirement was amended to include tactical bombing as well.

     Several companies responded with proposals to meet this requirement. North American proposed an improved version of its B-45 Tornado four-jet bomber. Boeing proposed an adaptation of its B-47 Stratojet six-jet medium bomber. Martin proposed a version of the B-51 3-engined low-level bomber. Most promising, however, was Douglas's proposal of a land-based version of the Navy's XA3D-1 Skywarrior twin-engined carrier-based strategic bomber that was then currently under development. However, the XA3D-1 was not scheduled to fly for yet another year and was somewhat of an unknown quantity.

     On August 29, 1951, Douglas formally issued a proposal for an adaptation of its XA3D-1 to meet this requirement. On November 29, 1951, the USAF Aircraft and Weapons Board announced that the Douglas design had been approved. The designation B-66 was assigned on January 12, 1952.

     The Air Force originally thought that the B-66 would be more or less an off-the-shelf copy of the A3D, so there would be no need for prototype XB-66. Instead, a small initial batch of pre-production aircraft designated RB-66A (Douglas Model 1326) would be acquired for test and evaluation purposes. There would be two separate production versions that would be acquired--a reconnaissance version designated RB-66B and a bomber version designated B-66B. The reconnaissance version would have the higher priority, and would be equipped with night photography capability and would carry electronic countermeasures and reconnaissance equipment.

     The general operational requirements were issued on January 21, 1952. A fast, highly-maneuverable tactical reconnaissance bomber was called for, with a 1000-nautical mile radius. It had to be capable of carrying at least a 10,000 pound load of atomic weapons, conventional bombs, or photographic flash bombs. The plane had to be capable of carrying large amounts of electronic equipment without adversely affecting its normal performance. In addition, defensive armament had to be carried and electronic countermeasures equipment was required to deal with enemy radars. Finally, the aircraft had to be simple and easy to maintain and had to be able to operate from makeshift or temporary runways.

     Letter Contract AF 33(600)-9646 was issued on February 12, 1952, calling for the acquisition of a test quantity of 5 RB-66As. It was decided that it would not be worthwhile to acquire any examples of the Navy A3D because by now it was anticipated that the Air Force version would be quite different. The definitive contract was signed on December 4, 1952. 127 production aircraft were ordered in Letter Contract AF 33(600)-16314, signed on April 24, 1952.

     The design of the B-66 was assigned to a Douglas-Long Beach team under the direction of John C. Buckwalter. Work on the project began in early 1952. The B-66 shared the same basic configuration of the A3D, with a high-mounted sweptback wing with negative dihedral. The two engines were mounted in pods attached to underwing pylons. The crew of three were seated together in a cockpit in the forward part of the nose. The main landing gear members retracted into wells in the rear fuselage.

     The first step in the design was the elimination of the features of the Navy A3D that were specific to its carrier-based role, such as folding wings, arrester gear, and catapult harnesses. This was fairly simple to do.
The next step was not so straightforward. An early problem was the fact that the A3D did not have ejector seats, the crew escaping the aircraft via a chute in the rear of the cockpit. Since the B-66 would be flying at low altitudes and at fairly high speeds (the A3D was envisaged as a high-altitude strategic bomber), upward-firing ejector seats for the three crew members had to be provided. The use of ejector seats in turn required that the cockpit canopy be extensively revised to accommodate the escape hatches needed for the ejecting crew. In addition, the cockpit itself had to be extensively revised, with the pilot sitting centrally forward and the navigator and gunner/reconnaissance system operator seated immediately aft.

     Because of the low altitudes and high speeds that were anticipated, the airframe structure had to be strengthened. The wing had a revised planform with a reduced thickness/chord ratio at the root. New ailerons and flaps were fitted. In addition, the 30-inch radar antenna of the A3D had to be replaced by a 45-inch antenna for the APS-27 and K-5 bombing and navigation radar. Since the R/B-66 had to be capable of operating from semi-improved or temporary airfields, larger landing gear tires were required. New emergency air brakes, wing spoilers, improved lateral controls, and a two percent reduction in the wing angle of incidence were needed to minimize Dutch roll. The hydraulic system had to be revised and the fuel system had to be redesigned. The photo-navigator station had to be relocated, and the aircraft had to be fitted for inflight refueling. For the reconnaissance mission, a battery of four cameras was to be mounted in the center fuselage bay. A new remotely-controlled General Electric tail turret with two 20-mm cannon was fitted as the defensive armament.

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