Requiring a successor for their aging Douglas A-26 Invader fleet, the United States Air Force (USAF) contracted with the Douglas Aviation Company to secure a land-based light tactical bomber variant of the carrier-based A-3 Skywarrior in service with the United States Navy (USN). The aircraft was only slightly revised but incorporated certain features required by the USAF and was adopted as the B-66 "Destroyer". The aircraft was introduced during 1956 and 294 total examples were procured. The RB-66 became a notable photographic reconnaissance mark which was ordered into development at the same time as the B-66 bomber form.



Following the A-3 Skywarrior lines, the B-66 utilized a long, slab-sided fuselage with a stepped cockpit flightdeck. Wings were high-mounted along the fuselage roof and swept rearwards, each with an underslung engine nacelle. The tail incorporated a large-area vertical tail fin and mid-mounted horizontal planes as normal. The undercarriage was wheeled and wholly retractable. Power was served through 2 x Allison J71-A-11 turbojet engines developing 10,200lb of thrust each. Standard armament became 2 x 20mm M24 series autocannons held in a remote-controlled, radar-assisted tail turret to counter following threats. An internal bomb bay allowed for up to 15,000lb of conventional drop ordnance to be carried. The operating flight crew numbered three and all positions were given ejection seats - a feature lacking in the USN's A-3 line.



USAF authorities bypassed the prototype development phase and entered into preproduction thinking with a focus on the RB-66A photographic reconnaissance platform before the low-level tactical bomber product. However, the USAF requirements began to delay the program considerably and the once-simply conversion process was beginning to bog down into a laundry list of required changes by the branch. Despite the slow progress, five preproduction RB-66A models were eventually realized and a flyable form first took to the air on June 28th, 1954.



Production of A-models ended with the fifth airframe received. This paved the way for the RB-66B variant of which 149 were produced. These were based on the RB-66A but were heavier and installed the Allison J71-A-13 series turbojet engines instead. This aircraft first flew in early 1955.



The B-66 light tactical bomber form was eventually evolved along its own set of requirements, ultimately yielding the B-66B production model of which 72 were obtained by the USAF. The USAF originally envisioned a fleet of 141 of the type but the numbers never worked out in the branch's favor. The B-model eventually formed the basis for the RB-66C, an Electronic CounterMeasures (ECM) model which added specialized mission equipment and an additional four crewmembers operating in a new work area where the internal bomb bay once resided. This mark totaled 36 examples and were easily differentiated by their wingtip pods. EB-66C models were RB-66Cs with modernized ECM equipment while the EB-66E was a highly specialized ECM version of the RB-66B. The WB-66D was a special weather-minded reconnaissance platform with a crew of five. 36 of this mark were produced. The WB-66D later formed the basis for a pair of Northrop X-21A experimental aircraft intended for laminar flow control wing testing by NASA.



Over the course of its service life, the B-66/RB-66 took on sorties involving the Cuban Missile Crisis and the Vietnam War. Most of its career centered on the reconnaissance role where valuable data on enemy positions was essential to upcoming offensives and air strikes. ECM versions also supplied the necessary jamming of North Vietnam air defense radar systems coupled to deadly ground-based fire and Surface-to-Air Missile (SAM) emplacements. The line was formally retired during 1975 as its battlefield roles were taken on by more modern mounts. Some examples managed extended service lives in testing programs and as museum showpieces.