After flying the little XF-92A delta demonstrator in 1948, Convair used its delta experience to offer a bomber design for Air Force study. On February 17, 1951, Convair signed a letter contract to develop a parasite delta, called the MX-1626, which could be carried by a B-36, and on February 26, Boeing got a similar design contract for a more conventional MX-1712 proposal.
Revised USAF requirements issued February 26, 1952, led to Convair’s MX-1964 and Boeing’s MX-1965 three-place supersonic medium bomber designs, which became the XB-58 and XB-59. Boeing used four General Electric J73s and a swept wing, but when both detail designs were presented, Convair’s delta was chosen on November 18. A mockup was inspected in August 1953, and the design was finalized after the J79 engine was chosen.
Development of 13 YB-58 test aircraft from Fort Worth was authorized June 29, 1954, although the definitive contract was not approved until December, 1955. Beryl Erickson flew the first YB-58 November 11, 1956, with four General Electric YJ79-GE-1 turbojets and afterburners in pods below the conical-cambered delta wing.
The narrow area-ruled fuselage had pressurized compartments for three crewmen provided with tandem ejection seats, and honeycombed wing skin panels resisted the high temperatures of supersonic air friction. Aircraft size was too small for a bomb bay. Instead, the stilted 18-wheel retractable landing gear held the narrow area-ruled fuselage high enough to clear an MB-1C pod containing a W39Y-1 nuclear warhead and 4,172 gallons of fuel. A similar pod with cameras, the LA-331, was available for reconnaissance missions.
The bomb pod, slung beneath the fuselage, was carried at Mach .91 cruising speed and released on a Mach 2 dash over the target at 55,000 feet. Air refueling could increase combat radius from 1,750 to 5,590 miles. A dual pod, the BLU-2B flight-tested May 12, 1960, had a 54-foot lower 3,962-gallon fuel section released before the 35-foot upper section with a BA53-Y1 warhead. This configuration allowed a Mach .91 sea-level attack capability for that nine-megaton weapon. Hard points for four 2,065-pound, one-megaton Mk 43 weapons were added and a B-58 made the first supersonic weapons drop on June 16, 1962.
Navigation and bombing at Mach 2 presented unusual problems, which on the B-58 were to be solved by a Sperry AN/ASQ-42 system which used active radar navigation during a mission’s approach phase, with inertial and star-tracking methods employed over enemy territory. Weighing 1,948 pounds, the system had an analog computer receiving data from search radar in the nose, an astro star tracker amidships, a Doppler radar in the tail, inertial sensors, and radio altimeter. Sitting at his console behind the pilot, the bombardier-navigator was provided with continuous and precise information on aircraft position, heading, ground speed, altitude, steering data, and distance to target, as well as ballistic computations for weapons release. Unfortunately, not until 1967 was the system’s reliability satisfactory.
The third crewman was the defense systems operator, who, seated behind the navigator, had an Emerson MD-7 fire control for a 20-mm M-61 Vulcan with 1,120 rounds, and a 60-degree cone of fire in the tail. Electronic countermeasures, including 200 pounds of chaff in the wings were provided. Beginning with the 8th aircraft, the gun and J79-GE-5A engines were fitted, and new crew escape capsules were provided in 1962.
The first 30 Hustlers were built as test ships, but ten were modified to the B-58A tactical configuration and eight to dual-control TB-58A trainers. Eighty-six more standard B-58As with J79-GE-5Bs were delivered from September 1959 to October 26, 1962, also the B-52’s last delivery day. Flyaway cost per production B-58 was listed as 12.44 million dollars, including about six million for engines, electronics, and armament. B-58 operations were said to be three times B-52 costs.