Convair YB-60

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YB-60
The Convair YB-60.jpg
YB-60 prototype, Convair B-36F in the background
Role Strategic bomber
Manufacturer Convair
First flight 18 April 1952
Status prototype only
Primary user United States Air Force
Number built 1 complete, 1 nearly complete
Developed from Convair B-36

The Convair YB-60 was an American prototype bomber aircraft for the United States Air Force.

Design and development[]

The YB-60 landing at Rogers Dry Lake, California.

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, it authorized Convair to convert two B-36Fs (49-2676 and 49-2684) as the B-36G. Since the aircraft was so radically different from the existing B-36, the designation was soon changed to YB-60.

The YB-60 had 72% parts commonality with its piston-engined predecessor. The fuselages of the two aircraft were largely identical although the radar and bombing systems were located in a removable nose section as a result of the poor reliability of the B-36 installation. For initial flight testing a more streamlined nose with an instrumented boom was fitted; a wedge-shaped insert was added just outboard of the main landing gear to increase wing sweep and the tail surfaces were swept to match. The swept wings also used many B-36 parts. A steerable tail wheel was added to prevent the aircraft tipping backwards. It was not necessarily extended when on the ground but depended on how the aircraft was loaded.[1]

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. Prior to this engine configuration Convair had evaluated a six-turboprop design and one with 12 J47 engines.[2]

The first YB-60 prototype's crew numbered five; the second prototype's numbered nine, as it did in the planned production B-60s. Production B-60s were to have defensive armament similar to those of the B-36.[3]

Convair YB-60 serial number 49-2676 made its maiden flight on 18 April 1952, piloted by Beryl Erickson. The Boeing YB-52 beat the Convair aircraft into the air by three days. 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 lb (33,000 kg) against 43,000 lb (20,000 kg) 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 pounds (27,000 kg). The flight test programs were canceled on 20 January 1953, with 66 flying hours accumulated. The second prototype was nearing completion but it was not fitted with much equipment. Since Convair completed their prototype contract satisfactorily, both YB-60s were formally accepted by the Air Force in 1954. The operational aircraft never flew again, and both airframes were scrapped by July.

An airliner adaptation of the YB-60 was proposed by Convair, but its wingspan and weight would have required unacceptable airport infrastructure changes beyond those required for the upcoming Boeing 707. The company decided to pursue the Convair 880 series airliner instead.[4]

Specifications (YB-60)[]

The YB-60 in flight.

Data from [5]

General characteristics

  • Crew: 5 (two pilots, navigator, bombardier/radio operator, radio operator/tail gunner)
  • Length: 171 ft (52 m)
  • Wingspan: 206 ft (63 m)
  • Height: 60 ft 6 in (18.44 m)
  • Wing area: 5,239 sq ft (486.7 m2)
  • Airfoil: root: NACA 63(420)-422 Mod.; tip: NACA 63(420)-517[6]
  • Empty weight: 1,530–16 lb (694–7 kg)
  • Gross weight: 160,000 lb (72,575 kg)
  • Max takeoff weight: 300,000 lb (136,078 kg)
  • Powerplant: 8 × Pratt & Whitney J57-P-3 turbojet engines, 8,700 lbf (39 kN) thrust each

Performance

  • Maximum speed: 508 mph (818 km/h, 441 kn) at 29,250 ft (8,915 m)
  • Stall speed: 115 mph (185 km/h, 100 kn)
  • Combat range: 2,920 mi (4,700 km, 2,540 nmi)
  • Ferry range: 8,000 mi (13,000 km, 7,000 nmi)
  • Service ceiling: 53,300 ft (16,200 m)
  • Rate of climb: 1,060 ft/min (5.4 m/s)
  • Wing loading: 31 lb/sq ft (150 kg/m2)
  • Thrust/weight: 0.44

Armament

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

See also[]

Related development

  • Convair B-36

Aircraft of comparable role, configuration, and era

Related lists

References[]

  1. ^ Magnesium Overcast, The Story of the Convair B-36,Dennis R. Jenkins 2001-2002,ISBN 978 1 58007 129 1, p.190/201
  2. ^ Magnesium Overcast, The Story of the Convair B-36,Dennis R. Jenkins 2001-2002,ISBN 978 1 58007 129 1, p.188
  3. ^ Jenkins, D.R., 2001. Magnesium Overcast: The Story of the Convair B-36. Specialty Press. ISBN 978-1-58007-201-4.
  4. ^ Magnesium Overcast, The Story of the Convair B-36,Dennis R. Jenkins 2001-2002,ISBN 978 1 58007 129 1, p.201
  5. ^ "Convair YB-60".
  6. ^ Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
  • 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.

External links[]

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