WS-110A

WS-110A ("Weapon System 110A") was a project by the United States Air Force in the 1950s to develop a supersonic bomber aircraft capable of delivering nuclear weapons. Proposals for such an aircraft were submitted by Boeing and North American Aviation, and although the program was put on indefinite hold before any actual designs were completed, it paved the way for the XB-70 Valkyrie project.

History

In October 1954, the Air Force issued General Operational Requirement No. 38, which was quite general and called simply for an intercontinental manned bomber which would replace the B-52 beginning in 1965. March 1955's GOR.81 was more specific, calling for a nuclear-powered bomber with a combat radius of 11,000 nautical miles, capable of flying up to 1,000 miles at a speed greater than Mach 2 at altitudes greater than 60,000 feet with a 20,000 lb payload, revising this to 25,000 lb in GOR.82 later that month. [http://home.att.net/~jbaugher2/b70.html North American XB-70A Valkyrie] , J Baugher.] Jenkins 1999, Ch. 1]

The Air Research and Development Command (ARDC) decided to separate the two approaches, and issued a requirement for "Weapon System 110A", which asked for a Mach 0.9 cruising speed and "maximum possible" speed during a 1000-mile entrance and exit from the target. The target date for the first operational wing of these bombers was July 1964, reduced a year in comparison to earlier GOR's. The nuclear approach became "Weapon System 125A", while the ICBM work was organized under "Weapon System 107A". [ [http://www.unrealaircraft.com/classics/xb70.php Lost Classics - North American XB-70 Valkyrie] ]

In early 1955, the Air Force issued GOR.96, which called for an intercontinental reconnaissance system with the same general requirements as WS-110A, called WS-110L. Pace 1986, p. 14.] The two requirements were combined soon afterwards, becoming Weapon System 110A/L. The nuclear-powered version was dropped during this period, given the problems in that program's development, as well as a general feeling of optimism about the zip fuels. In June 1955 the Air Staff directed that the details of WS-110A/L be released to the aviation industry and that a request for proposals be issued. Although six contractors were given the requirements, only Boeing and North American Aviation (NAA) submitted proposals. On 8 November 1955, the Air Force issued letter contracts to both Boeing and North American for Phase 1 development. The contracts called for models, design reports, wind tunnel tests, plus a mock-up.

In 1956, initial designs were presented by the two companies. Although zip fuels improved range, the overall effect was not very large, perhaps 10%, so both designs featured huge wingtip fuel tanks that could be jettisoned before a supersonic run on the target. In the case of the North American design, the entire outer portion of the wings was jettisoned as well, resulting in an aircraft that looked somewhat like a very large F-104 Starfighter after being "broken up".

The Air Force evaluated their designs and in September 1956 deemed them too large and complicated; the huge fuel load resulted in takeoff weights of 700,000 pounds, making safe operation from existing runways extremely difficult. They were also far too large to fit in existing hangars. Curtis LeMay was not enthusiastic about the design, claiming "Hell, this isn't an airplane, it's a three-ship formation." [ [http://www.unrealaircraft.com/classics/xb70.php Lost Classics - North American XB-70 Valkyrie] ] NAA and Boeing's study contracts were extended to further develop their bomber designs. The next month the program was put "on hold", although the companies were told to continue any low-level development they could.

References

* Jenkins, Dennis R. and Candis, Tony R. "Valkyrie: North American's Mach 3 Superbomber" Specialty Press, 2004. ISBN 1-58007-072-8
* Jenkins, Dennis R. " B-1 Lancer, The Most Complicated Warplane Ever Developed". New York: McGraw-Hill, 1999. ISBN 0-07-134694-5.
* Pace, Steve. "Triplesonic Twosome." "Wings" Volume 18, No. 1, February 1988.