Convair RB-58 Hustler

Introduction

The Convair RB-58 Hustler was the first supersonic bomber to be put into operational service, entering service with the USAF in March 1959. It represented a new breed of strategic reconnaissance aircraft intended to enter hostile airspace and eliminate the defenses there, combining the roles of fighter, reconnaissance aircraft and bomber. It continued these duties from the 1960s through to the early 1990s. The type is best known from an early member of the production run, the famous RB-58C Marisol

Early Development

The origin of the B-58 can be traced back to the period just after the end of the Second World War. In September 1948, following the first Red Sun exercise Curtis E. LeMay, wrote a letter to Lt. Gen. Nathan F. Twining, chief of the Air Materiel Command, to request that work begin on a new jet- powered medium bomber that would be ready for service by the late 1950s. This bomber, the XB-55, should have a combat radius of 2500 miles, a cruising speed of at least 500 mph, and a gross weight of 170,000 pounds. It was proposed that the development of such an aircraft would follow the development of the B-52. A developed version of this aircraft would fulfill the role of strategic reconnaissance aircraft, replacing the modified heavy bombers that had previously been used for this role.

The XB-55 was cancelled early with the general cut-back of tactical and medium-bomber aviation in the early 1950s but the strategic reconnaissance aircraft gained in urgency as the decade progressed. In April of 1950, the specification was changed to provide for a radius of 3500 to 4500 miles, with speeds as great as Mach 1.5. On January 26, 1951, following the completion of the detailed study, Convair proposed that it develop a long range supersonic reconnaissance bomber capable of carrying 10,000 pounds of bombs. It had to be capable of operating in all weather conditions, and had to be able to achieve a combat radius of 5000 miles with a single outbound inflight refuelling. It had to be capable of supersonic performance at altitudes of 50,000 feet or more and of high subsonic performance at lower altitudes. It was considered important that the aircraft be fairly small, since this would reduce the radar reflectivity and make the aircraft harder to detect. The Air Force wanted production to begin within five years.

On December 2, 1952, it was announced that the designation of the new bomber would be B-58. The Deputy Chief of Staff for Development endorsed a production schedule based on the four-year procurement of 244 B/RB-58s. The first 30 would be used for testing, and they would be reworked on the production line as problems appeared and were solved. This plan was based on the "Cook-Cragie" philosophy, in which the prototype phase was skipped. This plan, named for General Laurence C. Cragie, Deputy Chief of Staff for Development, and Orval R. Cook, Deputy Chief of Staff for Materiel, was rather risky and was really applicable only when there is a fairly high degree of certainty that the aircraft is actually going to go into production. At this point, only the basic concept had been approved, not any detailed design. On March 20, the Air Force indicated its acceptance of a firm configuration with a 60-degree delta wing with the trailing edge swept forward by ten degrees. A small amount of leading edge camber was provided to reduce drag due to lift. The aircraft was to be powered by four General Electric J79 turbojet engines, with the two inboard units mounted on underwing pylons and the two outboard engines mounted on the wing upper surface.

The first development engineering inspection took place on August 17/18, 1953. At this stage, the B-58 mockup was known as Configuration II. The requirements matched fairly closely with the specifications issued by Convair in August 1952 as well as with the USAF demands issued in the September 1952 GOR. At this stage in the design, the fuselage of the B-58 still consisted of an upper component and a lower pod that were integral with each other rather than being separated by a pylon. The return component had a flat fuselage undersurface once the disposable pod component had been jettisoned. In addition, nose gear requirements were complicated by the fact that both the pod and the return component required a nose gear. In the development engineering inspection of August 1953, it became obvious that this pod would have to be completely redesigned. In October 1953, the Air Force authorized Convair to shorten the pod to a length of 30 feet and to separate it from the fuselage by a pylon. In addition, the search radar was taken out of the pod and put in the nose of the upper compartment. The droppable nose gear was eliminated, and external fuel tanks were added to compensate for the fuel lost due to the shorter pod, and the positions of the navigator/bombardier and defensive systems operator were reversed.

In August 1954, what was to prove to be the final B-58 configuration was chosen. The engines were now mounted inside four individual underwing pylons, and all fuel was contained internally and in the podded lower component. The fuselage was aligned to the modified transonic area rule for supersonic speeds. The external wing tanks were eliminated, and the tail area was increased to 160 square feet. By December of 1955 a definitive contract was issued to Convair for 13 aircraft and 31 pods. These pods were in varying configurations, some containing fuel, some fuel plus a nuclear device, some a mix of missiles, others reconnaissance equipment.

Variants

Convair B-58A Hustler

The first group of aircraft off the production line, the B-58A was equipped as a bomber and served primarily as a training aircraft and group hack for the strategic reconnaissance groups. Its primary importance is that it was seen by the US Navy as a solution for its need to replace the subsonic P2B-2 Stratojet land-based maritime attack bombers. The B-58A production run was therefore cut short while Navy needs were filled and the definitive strategic reconnaissance RB-58 developed.

Specification of Convair B-58A Hustler

Powerplants: Four General Electric J79-GE-5A/5B axial flow turbojets, each rated at 9700 lb.s.t. normal power, 10,300 lb.s.t. military power, and 15,600 lb.s.t. maximum afterburner. Performance: Maximum speed: Mach 2.2 at 40,000 feet, Mach 0.91 at sea level. Cruising speed 521 knots. Takeoff ground roll 7850 feet at 160,000 pounds. Landing ground roll 2615 feet at 63,100 pounds. Maximum initial climb rate 38,650 feet per minute at sea level. An altitude of 30,000 feet could be attained in 11.2 minutes. Normal cruise altitude 38,450 feet. Target area altitude was 55,900 feet. Combat ceiling 63,400 feet. Maximum ferry range 4100 nautical miles. Weights: 55,650 pounds empty (without pod). Maximum gross weight 176,890 pounds (in flight). 63,100 pounds landing weight. Dimensions: Wingspan 56 feet 9.9 inches, length 96 feet 9.4 inches, height 29 feet 11 inches, wing area 1364.69 square feet. Armament: One General Electric T-171E-3 remotely-contolled cannon in tail with 1200 rounds. Offensive weapons consisted of one MB-1C pod containing a W39Y1-1 variable-yield thermonuclear warhead, or a a Two-Component Pod with a Mk.53 thermonuclear warhead. In addition, four Mk.43 thermonuclear weapons could be carried on external pylons underneath the wings between the fuselage and the main landing gear bays.

Convair PB5Y-1 Hustler

The Navy derivative of the B-58, the only difference between the PB5Y-1 and the B-58A was the dark blue paint job replacing SAC’s natural metal and different radios, communications and navigation equipment. Total production of the PB-5Y-1 totaled 200 aircraft, the type equipping two maritime strike groups.

Convair B-58B Hustler

The slightly enlarged and significantly more powerful B-58B was proposed by Convair as a follow-on to the B-58A. The B-58B introduced the J79-GE-10 engine that developed 17,890 pounds of thrust on afterburner. The fuselage was extended by 8 feet amidships to accommodate extra fuel and electronics equipment. Perhaps the most significant difference between the B-58B and the earlier B-58A was to have been in the B-58B being able to offer many more weapons options than the B-58A. In particular, the B-58B was to have had a significant conventional weapons capability, which the B-58A did not have. This was to have been made possible by fitting a new and significantly larger underfuselage pod capable of carrying more fuel. In addition, it was proposed that a pair of air-launched ballistic missiles be carried on underwing pylons just outboard of the centerline pod. Alternatively, an extra pair of fuel tanks could be carried on these underwing pylons. 37 B-58Bs were built for SAC.

Specification of Convair B-58B Hustler

Powerplants: Four General Electric J79-GE-10A/10B axial flow turbojets, each rated at 10,700 lb.s.t. normal power, 11,300 lb.s.t. military power, and 17,890 lb.s.t. maximum afterburner. Performance: Maximum speed: Mach 2.4 at 50,000 feet, Mach 0.95 at sea level. Cruising speed 551 knots. Takeoff ground roll 7650 feet at 160,000 pounds. Landing ground roll 2815 feet at 63,100 pounds. Maximum initial climb rate 39,650 feet per minute at sea level. An altitude of 30,000 feet could be attained in 9.2 minutes. Normal cruise altitude 48,450 feet. Target area altitude was 65,900 feet. Combat ceiling 68,400 feet. Maximum ferry range 4100 nautical miles. Weights: 55,650 pounds empty (without pod). Maximum gross weight 176,890 pounds (in flight). 63,100 pounds landing weight. Dimensions: Wingspan 56 feet 9.9 inches, length 104 feet 9.4 inches, height 29 feet 11 inches, wing area 1364.69 square feet. Armament: One General Electric M-61 remotely-controlled cannon in tail with 1200 rounds. Offensive weapons consisted of one MB-1C pod containing a W39Y1-1 variable-yield thermonuclear warhead, or a Two-Component Pod with a Mk.53 thermonuclear warhead. In addition, four Mk.43 thermonuclear weapons could be carried on external pylons underneath the wings between the fuselage and the main landing gear bays.

Convair PB5Y-2 Hustler

Navy equivalent of B-58B, 400 built.

Convair RB-58C Hustler

The RB-58C was the dedicated strategic reconnaissance version of the B-58 and the first of the type to see operational service with SAC. The RB-58C incorporated significant airframe modifications, including a new wing leading edge, a larger tail area and a 5-foot nose extension. The original bombing radar was moved to an under-nose gondola while the new nose radome was occupied by a multi-mode radar that was used for air-to-air and air-to-surface search. The aircraft had further improved engines, J79-GE-17s rated at 18,900 pounds thrust on afterburner. These engines were also optimized for high-altitude work.

Specification of Convair RB-58C Hustler

Powerplants: Four General Electric J79-GE-17A/17B axial flow turbojets, each rated at 11,700 lb.s.t. normal power, 12,600 lb.s.t. military power, and 18,900 lb.s.t. maximum afterburner. Performance: Maximum speed: Mach 2.5 at 60,000 feet, Mach 0.98 at sea level. Cruising speed 600 knots. Takeoff ground roll 7250 feet at 170,000 pounds. Landing ground roll 2815 feet at 63,100 pounds. Maximum initial climb rate 41,250 feet per minute at sea level. An altitude of 30,000 feet could be attained in 9.1 minutes. Normal cruise altitude 55,450 feet. Target area altitude was 70,900 feet. Combat ceiling 72,400 feet. Maximum ferry range 4400 nautical miles. Weights: 59,150 pounds empty (without pod). Maximum gross weight 196,890 pounds (in flight). 63,100 pounds landing weight. Dimensions: Wingspan 56 feet 9.9 inches, length 110 feet, height 29 feet 11 inches, wing area 1364.69 square feet. Armament: One General Electric M-61 remotely-controlled cannon in tail with 1200 rounds. Offensive weapons consisted of up to 12 nuclear-tipped air-to-air and air-to-surface missiles.

Convair RB-58D Hustler

The RB-58D had an improved multi-mode ASQ-18 radar that removed the need for a separate bombing radar and thus deleted the under-nose gondola of the C model.

Convair RB-58E Hustler

RB-58C and D models rebuilt with the engines of the RB-58F. An interim measure while new RB-58Fs were built.

Convair RB-58F Hustler,

The new-generation version of the RB-58, the RB-58F was powered by four non-afterburning Pratt & Whitney J58 turbojets rated at 23,000 pounds of thrust giving the aircraft the ability to cruise at supersonic speeds. The wing platform was changed with the leading edge inboard of the two inboard engines being extended forward to give a double-delta. The tail gun was replaced by a 30mm cannon.

Specification of Convair RB-58F Hustler

Powerplants: Four Pratt and Whitney J58-PW-20 axial flow turbojets, each rated at 23,000 lb.s.t. normal power, 25,600 lb.s.t. military power. Performance: Maximum speed: Mach 2.8 at 60,000 feet, Mach 0.99 at sea level. Cruising speed 1,620 knots. Takeoff ground roll 5250 feet at 195,000 pounds. Landing ground roll 3115 feet at 68,100 pounds. Maximum initial climb rate 45,550 feet per minute at sea level. An altitude of 30,000 feet could be attained in 6.1 minutes. Normal cruise altitude 65,450 feet. Target area altitude was 75,200 feet. Combat ceiling 78,400 feet. Maximum ferry range 5200 nautical miles. Weights: 63,150 pounds empty (without pod). Maximum gross weight 216,890 pounds (in flight). 69,100 pounds landing weight. Dimensions: Wingspan 58 feet 9.9 inches, length 110 feet, height 31 feet 2 inches, wing area 1564.69 square feet. Armament: One General Electric M-61 remotely-controlled cannon in tail with 1200 rounds. Offensive weapons consisted of up to 12 nuclear-tipped air-to-air and air-to-surface missiles.

Convair RB-58G Hustler

Development of the RB-58F equipped with the ELINT component of the Defensive Anti-Missile System equipping the B-70 Valkyrie. Obtained by rebuilding RB-58Fs

Convair RB-58H Hustler

New-build RB-58Gs with improved electronics. Replaced RB-58E aircraft

Convair RB-58J Hustler

Rebuild of RB-58G and RB-58H with new glass cockpit

Convair RB-58K Hustler

Modernized and rebuilt RB-58J aircraft produced as interim stage until RB-70 aircraft available.

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