Modern-Aviation

The Convair B-58 Hustler was the first operational jet bomber capable of Mach 2 flight. The aircraft was designed by Convair engineer Robert H. Widmer and developed for the United States Air Force for service in the Strategic Air Command during the 1960s. It used a delta wing, which was also employed by Convair fighters such as the F-102, with four General Electric J79 engines in pods under the wing. It carried five nuclear weapons; four on pylons under the wings, and one nuclear weapon and fuel in a combination bomb/fuel pod under the fuselage, rather than in an internal bomb bay.

Maximum speed: 2,132 km/h (1,325 mph) Range: 4,400 mi Length: 96.82 ft Wingspan: 56.79 ft Cruising speed: 981.70 km/h (610 mph) Passengers: 3

Adverse Flight Characteristics
While its performance and design were exceptional and appreciated, it was never easy to fly. This was caused by the 60° leading edge sweepback of its wing and was inherent in these types of delta wing platforms. It required a much higher angle of attack than a conventional aircraft, up to 9.4° at Mach 0.5 at low altitudes. If the angle of attack was too high, in excess of 17°, the bomber could pitch up and enter a spin. Several factors could prevent a successful recovery: if the pilot applied elevon, if the center of gravity was not correctly positioned, or if the spin occurred below 15,000 feet (4,600 metres), recovery might not be possible. The B-58 also had stall characteristics that were not conventional. If the nose was elevated, the bomber maintained forward motion without pitching down. Unless large amounts of power were applied, the descent rate increased rapidly. Another problem pilots faced was called "fuel stacking" and took place when the B-58 accelerated or decelerated. It was due to fuel moving in the tanks and causing sudden changes in the center of gravity. This could cause the aircraft to pitch or bank and subsequently lose control. The B-58 was very difficult to safely recover from the loss of an engine at supersonic cruise due to differential thrust.

The plane had very unusual takeoff requirements, with a 14° angle of attack needed for the rotation at about 203.5 knots (376.9 km/h; 234.2 mph) for a 150,000 pound combat weight. This poor takeoff performance was also evident with the high landing speed that necessitated a drogue parachute for braking.

Weapon Systems
The Sperry AN/ASQ-42 bombing/navigation system combined a sophisticated inertial navigation system with the KS-39 Star tracker (astro-inertial navigation system) to provide heading reference, the AN/APN-113 Doppler radar to provide ground speed and windspeed data, a search radar to provide range data for bomb release and trajectory, and a radar altimeter. The AN/ASQ-42 was estimated to be 10 times more accurate than any previous bombing/navigation system.

Defensive armament consisted of a single 20 mm (0.79 in) T-171E-3 rotary cannon with 1,200 rounds of ammunition in a radar-aimed tail barbette. It was remotely controlled through the Emerson MD-7 automated radar fire-control system only requiring the DSO to lock-on a selected target blip on his scope and then fire the gun; the system computing all aiming, velocity or heading differential, and range compensation. Offensive armament typically consisted of a single nuclear weapon, along with fuel tanks, in a streamlined MB-1C pod under the fuselage. Incurable difficulties with fuel leakage resulted in the replacement of the MB-1C with the TCP (Two Component Pod), which placed the nuclear weapon in an upper section while the lower fuel component could be independently jettisoned. This had the added benefit of allowing the pilot to "clean up" the aircraft for fuel efficiency or in case of emergency, while still retaining the (somewhat) more slim weapon.

The first prototype, serial number 55-660, was completed in late August 1956. The first flight took place in November 1956. A difficult and protracted flight test program involving 30 aircraft continued until April 1959. The final B-58 was delivered in October 1962.

From 1961 to 1963, the B-58 was retrofitted with two tandem stub pylons under each wing root, adjacent to the centreline pod, for B43 or B61 nuclear weapons for a total of five nuclear weapons per aircraft. Although the USAF explored the possibility of using the B-58 for the conventional strike role, it was never equipped for carrying or dropping conventional bombs in service. A photo reconnaissance pod, the LA-331, was also fielded. Several other specialized pods for ECM or an early cruise missile were considered, but not adopted. The late 1950s High Virgo air-launched ballistic missile was designed to be launched from the B-58 with four test launches of the High Virgo carried out by a B-58 to determine ballistic missile and anti-satellite weapon system capability.

Excessive Programme Expenditure
Through FY 1961, the total cost of the B-58 program was $3 billion ($58 billion in 2016 dollars). A highly complex aircraft, it also required considerable maintenance, much of which required specialized equipment and ground personnel. For comparison, the average maintenance cost per flying hour for the B-47 was $361, for the B-52 it was $1,025 and for the B-58 it was $1,440. The B-58 also cost three times as much to operate as the B-52. The cost of maintaining and operating the two operational B-58 wings equaled that of six wings of B-52s. This included special detailed maintenance for the nose landing gear, which retracted in a complicated fashion to avoid the center payload. Further, compounding this, the B-58 had an unfavorably high accident rate: 26 B-58 aircraft were lost in accidents, 22.4% of total production. The SAC senior leadership had been doubtful about the aircraft type from the beginning, although its crews eventually became enthusiastic about the aircraft. General Curtis LeMay was never satisfied with the bomber and after a flight in one declared that it was too small, far too expensive to maintain in combat readiness and required an excessive number of aerial refuelings to complete a mission. Although the high altitude ferry range of the B-58 was better than the B-47, the lack of forward basing resulted in a requirement for more KC-135 tanker support. Cost: $12.44 million.

General Characteristics
Crew: 3: pilot; observer (navigator, radar operator, bombardier); defense system operator (DSO; electronic countermeasures operator and pilot assistant).
Length: 96 ft 10 in (29.5 m)
Wingspan: 56 ft 9 in (17.3 m)
Height: 29 ft 11 in (8.9 m)
Wing area: 1,542 ft² (143.3 m²)
Airfoil: NACA 0003.46-64.069 root, NACA 0004.08-63 tip
Empty weight: 55,560 lb (25,200 kg)
Loaded weight: 67,871 lb (30,786 kg)
Max. takeoff weight: 176,890 lb (80,240 kg)
Zero-lift drag coefficient: 0.0068
Drag area: 10.49 ft² (0.97 m²)
Aspect ratio: 2.09
Powerplant: 4 × General Electric J79-GE-5A turbojet Dry thrust: 10,400 lbf dry thrust (52.9 kN) each
Thrust with afterburner: 15,600 lbf (69.3 kN) each