Convair YB-60

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 had 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; its tail surfaces were swept to match the wings and a wedge-shaped insert added at the wing root. The swept wings also used many B-36 parts.

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 15, the YB-60's crew numbered only ten. Production B-60s were to have defensive armament similar to the B-36.

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 slower than the YB-52 and also had severe handling problems. It carried a heavier bomb load—72000 lb against 43000 lb 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 60000 lb.

The flight test program was canceled on 20 January 1953 with 66 flying hours accumulated, and a second prototype was never completed. The airframe was built, but it was not fitted with engines or much other 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.