Convair B-58 Slider
Convair B-58 Hustler
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The Convair B-58 Hustler was the first operational jet bomber capable of Mach 2 flight. The aircraft was designed by Convair and developed for the United States Air Force (USAF) for service in the Strategic Air Command (SAC) 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 underwing pods; carried one nuclear weapon and fuel in a combination bomb/fuel pod under the fuselage, rather than in an internal bomb bay. Later on, four additional external hardpoints were added to allow five weapons to be carried.
Replacing the Boeing B-47 Stratojet medium bomber, it was originally intended to fly at high altitudes and supersonic speeds to avoid Soviet fighters. The B-58 was notorious for its sonic boom, which was often heard by the public as it passed overhead in supersonic flight.
The introduction of highly-accurate Soviet surface-to-air missiles forced the B-58 into a low-level-penetration role that severely limited its range and strategic value, and it was never employed to deliver conventional bombs. This resulted in only a brief operational career between 1960 and 1970 when the B-58 was succeeded by the smaller, swing-wing FB-111A.
Design and development
The genesis of the B-58 program was the Generalized Bomber Study (GEBO II) issued in February 1949 by the Air Research and Development Command (ARDC) at Wright-Patterson AFB, Ohio, for the development of a supersonic, long-range, bombardment aviation platform. The proposed bomber’s design and development was to begin less than two years after sustained supersonic flight had been achieved. Contractors who bid to perform the generalized study (that hopefully would lead to a development contract) included Boeing, Convair, Curtiss, Douglas, Martin and North American Aviation.
Convair, which had built the XF-92A and other delta-wing fighters, initially looked at swept and semi-delta configurations, then settled on the delta wing planform, which offered good internal volume for support systems and fuel. It also had low wing loading (for airframe size), permitting supersonic flight in the mid-stratosphere at 50,000 to 70,000 ft (15,000 to 21,000 m). The final Convair proposal, coded FZP-110, was a radical two-place, delta wing bomber design powered by General Electric J53 engines. The performance estimates included a 1,000 mph (1,600 km/h) speed and a 3,000-mile (4,800 km) range.
The Air Force chose Boeing (MX-1712) and Convair MX-1626 to proceed to a Phase 1 study. The Convair design, refined and redesignated the MX-1964, was chosen in December 1952 to meet the newly proposed SAB-51 (Supersonic Aircraft Bomber) and SAR-51 (Supersonic Aircraft Reconnaissance), the first General Operational Requirement (GOR) worldwide for supersonic bombers. In February 1953, the Air Force issued a contract to develop Convair’s design.
The resulting B-58 design was the first “true” USAF supersonic bomber program. The Convair design was based on a delta wing with a leading-edge sweep of 60° with four General Electric J79-GE-1 turbojet engines, capable of flying at Mach 2. Although its large wing made for relatively low wing loading, it proved to be surprisingly well suited for low-altitude, high-speed flight. It seated three (pilot, bombardier/navigator, and defensive systems operator) in separated tandem cockpits. Later versions gave each crew member a novel ejection capsule that could eject at an altitude of 70,000 ft (21,000 m) at speeds up to Mach 2. Unlike standard ejection seats of the period, a protective clamshell would enclose the seat and the control stick with an attached oxygen cylinder, allowing the pilot to continue to fly even “turtled up” and ready for immediate egress. The capsule was buoyant; the crewmember could open the clamshell, and use it as a life raft. Unusually, the ejection systems was tested with live bears and chimpanzees. The XB-70 would use a similar system with capsules of a different design.
To protect against the heat generated while cruising at Mach 2, the crew compartment, the wheel wells and electronics bay were pressurized and air conditioned. The B-58 was one of the first extensive applications of aluminum honeycomb panels, which bonded outer and inner aluminum skins to a honeycomb of aluminum or fiberglass.
The pilot’s cockpit was rather conventional for a large multi-engine aircraft. The electronic controls were ambitious and advanced for the day. The navigator and DSO’s cockpits featured wraparound dashboards with warning lights and buttons, and automatic voice messages and warnings from a tape system were audible through the helmet sets. Research during the era of all-male combat aircraft assignments revealed that a woman’s voice was more likely to gain the attention of young men in distracting situations. Nortronics Division of Northrop Corporation selected actress and singer Joan Elms to record the automated voice warnings. To those flying the B-58, the voice was known as “Sexy Sally.”
- Crew: 3
- Length: 96 ft 10 in (29.51 m)
- Wingspan: 56 ft 9 in (17.30 m)
- Height: 29 ft 11 in (9.12 m)
- Wing area: 1,542 sq ft (143.3 m2)
- Aspect ratio: 2.09
- Airfoil: root: NACA 0003.46; tip: NACA 0004.08
- Empty weight: 55,560 lb (25,202 kg)
- Gross weight: 67,871 lb (30,786 kg)
- Max takeoff weight: 176,890 lb (80,236 kg)
- Zero-lift drag coefficient: CD0.0068
- Frontal area: 10.49 sq ft (0.975 m2)
- Powerplant: 4 × General Electric J79-GE-5A afterburning turbojet, 10,400 lbf (46 kN) thrust each dry, 15,000 lbf (67 kN) with afterburner
- Maximum speed: 1,146 kn (1,319 mph; 2,122 km/h) at 40,000 ft (12,000 m)
- Maximum speed: Mach 2
- Cruise speed: 530 kn (610 mph; 982 km/h)
- Range: 4,100 nmi (4,718 mi; 7,593 km)
- Combat range: 1,740 nmi (2,002 mi; 3,222 km)
- Service ceiling: 63,400 ft (19,300 m)
- Rate of climb: 17,400 ft/min (88 m/s) at gross weight
- Lift-to-drag: 11.3 (subsonic, “clean configuration”)
- Wing loading: 44 lb/sq ft (210 kg/m2)
- Thrust/weight: 0.919 lbf/lb (0.00901 kN/kg)
- Guns: 1× 20 mm T171 cannon
- Bombs: 1× Mark 39 or B53 or 4× B43 or B61 nuclear bombs; maximum weapons load was 19,450 lb (8,820 kg)
- AN/APB-2 Bombing radar
- AN/APN-110 Doppler navigational radar (part of Sperry AN/ASQ-42 Navigation & Bombing System)
- AN/APN-170 Terrain-following radar
- AN/APR-12 Radar warning receiver
- Hughes Aircraft AN/APQ-69 podded Side looking airborne radar (mounted on RB-58A)
- Goodyear AN/APS-73 podded synthetic aperture radar (mounted on RB-58A)