The Douglas B-66 Destroyer was a light bomber designed specifically for the United States Air Force (USAF).
It was developed from the United States Navy’s A-3 Skywarrior, which was a heavy carrier-based attack aircraft.
The B-66 was intended to be a simple adaptation of the A-3 but with unnecessary naval features removed, as it would be strictly land-based.
However, due to the USAF’s diverse requirements, the B-66 underwent considerable alterations, which resulted in a significant portion of the design being original.
The B-66 maintained the three-man crew arrangement used in the A-3, but it had ejection seats, which the A-3 lacked.
It made its first flight on June 28, 1954, and entered service with the USAF in 1956.
The standard model of the B-66 was a bomber that replaced the aging Douglas A-26 Invader.
Alongside the bomber model, a photo reconnaissance model, designated as RB-66, was introduced.
Several other variants of the B-66 were developed, which led to its use in signals intelligence, electronic countermeasures, and weather reconnaissance operations.
These aircraft were commonly deployed to bases in Europe, where they could approach the airspace of the Soviet Union more easily.
During the Cuban Missile Crisis, multiple variants were deployed around Cuba.
The B-66 also saw action during the American intervention in the Vietnam War, where it was primarily used as a support aircraft for other aircraft active over the skies of North Vietnam and Laos.
The aircraft also conducted missions to map SAM and AAA sites in both countries.
The last examples of the B-66 were withdrawn from service in 1975.
The USAF originally planned to convert the A-3 design by removing carrier-specific features and incorporating USAF avionics.
No prototypes were ordered, and instead, five pre-production RB-66A models were supplied, prioritizing the aerial reconnaissance mission.
However, multiple new variants were added, and modifications were made, resulting in an entirely new aircraft.
The B-66 was required to perform low-level operations, unlike the A-3, which was developed as a high-altitude nuclear strike bomber.
Design changes were made due to intense rivalry between the two services, with some being unnecessary, according to aviation authors Bill Gunston and Peter Gilchrist.
The fuselage and wing were redesigned, and the B-66 used two Allison J71 engines, which generated less thrust and were more fuel-hungry than the J57 engine already in USAF use.
As a result of the engine change, the power system was completely redesigned, with hydraulic pumps and generators repositioned onto the engines.
The pressurized crew compartment had a different structure, with a deep glazed front position for the pilot.
The landing gear was redesigned, and the B-66 was equipped with ejection seats, a feature the A-3 lacked entirely. Variants RB-66A (Douglas Model 1326) All-weather photo-reconnaissance variant, five built. RB-66B (Douglas Model 1329) A variant of the RB-66A with production J71-A-13 engines and higher gross weight, 149 built. B-66B (Douglas Model 1327A) Tactical bomber variant of the RB-66B, 72 built. NB-66B One B-66B was used for testing and an RB-66B was used for F-111 radar trials. RB-66C The electronic reconnaissance variant of the RB-66B included an additional compartment for four equipment operators, 36 built. EB-66C Four RB-66Cs with uprated electronic countermeasures equipment. WB-66D Electronic weather reconnaissance variant with the crew compartment modified for two observers, 36 built with two later modified to X-21A. EB-66E Specialized electronic reconnaissance conversion of the B-66B. Northrop X-21 The Northrop X-21 aircraft underwent modification from the WB-66D to carry out experiments on laminar flow control. The ultimate goal of this research was to reduce drag by a significant margin of up to 25%. The method employed involved the use of porous materials, narrow surface slots, or small perforations to eliminate a small amount of boundary-layer air. Northrop commenced flight research in April 1963 at Edwards Air Force Base. Unfortunately, despite the initial progress made, the X-21 became the final experiment undertaken utilizing this concept due to various challenges and the allocation of funds toward war efforts. Specifications Crew 3 Length 75 ft 2 in (22.91 m) Wingspan 72 ft 6 in (22.10 m) Height 23 ft 7 in (7.19 m) Wing area 780 sq ft (72 m2) Empty weight 42,549 lb (19,300 kg) Gross weight 57,800 lb (26,218 kg) Max take-off weight 83,000 lb (37,648 kg) Powerplant 2 × Allison J71-A-11 (later Allison J71-A-13) turbojet engines, 10,200 lbf (45 kN) thrust each. Performance Maximum speed 548 kn (631 mph, 1,015 km/h) at 6,000 ft (1,800 m) Cruise speed 459 kn (528 mph, 850 km/h) Combat range 782 nmi (900 mi, 1,448 km) Ferry range 2,146 nmi (2,470 mi, 3,974 km) Service ceiling 39,400 ft (12,000 m) Rate of climb 5,000 ft/min (25 m/s) Wing loading 74.1 lb/sq ft (362 kg/m2) Armament Guns 2 × 20 mm M24 cannon in radar-controlled/remotely operated tail turret Bombs 15,000 lb (6,800 kg) Avionics APS-27 and K-5 radars.
Sources Douglas B-66 Destroyer-Rene J Francillon, Mick Roth. McDonnell Douglas aircraft since 1920: Volume I-René J Francillon. San Diego Air and Space Museum Archive. The National Museum of the U.S. Air Force.