Convair YB-60

Picture - YB-60 prototype, Convair B-36F-5 is in the background.

Role: Strategic bomber
Manufacturer: Convair
First flight: 18 April 1952
Status: Canceled 14 August 1952
Number built: 2
Program cost: US$14.3 million for program
Developed from: Convair B-36

The Convair YB-60 was an American experimental bomber prototype for the United States Air Force canceled on 14 August 1952.

Design and development

On 25 August 1950, Convair issued a formal proposal for a swept-winged version of the B-36 with all-jet propulsion. The United States Air Force was sufficiently interested that on 15 March 1951, the USAF authorized Convair to convert two B-36Fs (49-2676 and 49-2684) as B-36Gs. Since the aircraft was so radically different from the existing B-36, the designation was soon changed to YB-60.

The YB-60 betrayed its 72% parts commonality with its piston-engined predecessor. The fuselages of the two aircraft were largely identical, although the YB-60 had a longer, pointed nose with a needle-like instrument probe, instead of the B-36's rounded nose, and the tail surfaces were all new, swept to match the wings, instead of the B-36's more antiquated design. The swept wings used a lot of B-36 parts, with a wedge-shaped insert at the wing root to sweep the wings back more than the B-36's wings.

The YB-60's unofficial competitor for an Air Force contract was Boeing's B-52 Stratofortress. Convair's proposal was substantially cheaper than Boeing's since it involved modifying an existing design rather than starting from scratch. Like the B-52, it was powered by eight Pratt & Whitney J57-P-3 turbojets mounted in pairs in four pods suspended below the wing.

Instead of the B-36's crew of fifteen, the YB-60's crew numbered only 10. Production B-60s were to have similar defensive armament to the B-36.

Convair YB-60 serial number 49-2676 made its maiden flight on 18 April 1952, piloted by Beryl Erickson. The Convair aircraft beat the Boeing YB-52 into the air by three days, but it was soon obvious that it would win few other contests against Boeing's bomber. The YB-60 was approximately 100 mph (160 km/h) slower than the YB-52 and also had severe handling problems. It did carry a heavier bomb load - 72,000 pounds against 43,000 pounds (20 t) for the YB-52 - but the Air Force did not see the need for the extra capacity given the YB-60's other drawbacks. (Later "big belly" modifications increased the B-52's bomb load to 60,000 lbs)

Accordingly, the flight test program was canceled on 20 January 1953 with 66 flying hours accumulated, and a second prototype never completed. The airframe was built, but it was not fitted with engines or much other equipment. Since Convair had completed its prototype contract satisfactorily, both the YB-60s were formally accepted by the Air Force in 1954. The operational aircraft never flew again, and both airframes were scrapped by July.

Specifications (YB-60)

Picture - A YB-60 in flight.

General characteristics

Crew: 5
Length: 171 ft (52.1 m)
Wingspan: 206 ft (62.8 m)
Height: 60 ft 6 in (18.4 m)
Wing area: 5,239 ft² (486.7 m²)
Empty weight: 153,016 lb (69,407 kg)
Loaded weight: 160,000 lb (73,000 kg)
Max takeoff weight: 300,000 lb (140,000 kg)
Powerplant: 8x— Pratt & Whitney J57-P-3 turbojets, 8,700 lbf (38 kN) each

Performance

Maximum speed: 508 mph (411 knots, 818 km/h) at 29,250 ft (8,915 m)
Stall speed: 115 knots (132 mph, 212 km/h)
Combat radius: 2,920 mi (2,540 nm, 4,700 km)
Ferry range: 8,000 mi (7,000 nm, 13,000 km)
Service ceiling: 53,300 ft (16,200 m)
Rate of climb: 1,060 ft/min (5.38 m/s)
Wing loading: 31 lb/ft² (150 kg/m²)
Thrust/weight: 0.44

Armament

Guns: 2x— 20 mm (0.787 in) cannon in tail
Bombs: 72,000 lb (33,000 kg)

Related development

Convair B-36

Comparable aircraft

Boeing B-52 Stratofortress
Myasishchev M-4 Molot
Tupolev Tu-95

Jacobsen, Meyers K. and Wagner, Ray. B-36 in Action (Aircraft in Action No.42). Carrollton, TX: Squadron/Signal Publications, Inc., 1980. ISBN 0-89747-101-6.
Jones, L.S. U.S. Bombers, B-1 1928 to B-1 1980s. Fallbrook, CA: Aero Publishers, Inc., 1962 (second edition 1974). ISBN 0-8168-9126-5.

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Source: WikiPedia