WS-110A
Encyclopedia
WS-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
. Although the program was put on indefinite hold before any actual designs were completed, it paved the way for the B-70
program.
s of the time had poor fuel efficiency
. An aircraft capable of carrying a reasonable bomb load to the Soviet Union
from the continental United States had to carry a large fuel load (and thus be very large itself) due to the unrefueled range required.
The aviation industry had been examining this problem for some time. There was considerable interest in the use of nuclear powered aircraft in the bomber role from the mid-1940s. Nuclear engines in aircraft
used the heat generated by a nuclear reactor
in place of jet fuel, giving it virtually unlimited cruising range. In addition to solving the range issue, these aircraft could be flown to holding areas away from the airbases and kept in the air for extended periods of time, making them immune to sneak attack. Accordingly, Boeing developed plans for a nuclear powered bomber equipped with afterburners that used chemical fuel. Lockheed
and Convair
proposed similar designs.
Another possibility was the use of boron
-enriched "zip fuel
s", which improved the energy density
of the fuel by about 40%. Various U.S. government agencies had been experimenting with zip fuels for some time, and they believed that once the problems were solved, zip fuel would become almost universal for high-speed aircraft. Although the advantages of a zip-fueled aircraft would not be as great as those of a nuclear powered one, it would offer a real performance increase and was a relatively straightforward development of existing engines and fuels.
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 miles (1,609.3 km) 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".
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. 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 fuel
s 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." 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.
United States Air Force
The United States Air Force is the aerial warfare service branch of the United States Armed Forces and one of the American uniformed services. Initially part of the United States Army, the USAF was formed as a separate branch of the military on September 18, 1947 under the National Security Act of...
in the 1950s to develop a supersonic bomber aircraft capable of delivering nuclear weapons. Proposals for such an aircraft were submitted by Boeing
Boeing
The Boeing Company is an American multinational aerospace and defense corporation, founded in 1916 by William E. Boeing in Seattle, Washington. Boeing has expanded over the years, merging with McDonnell Douglas in 1997. Boeing Corporate headquarters has been in Chicago, Illinois since 2001...
and North American Aviation
North American Aviation
North American Aviation was a major US aerospace manufacturer, responsible for a number of historic aircraft, including the T-6 Texan trainer, the P-51 Mustang fighter, the B-25 Mitchell bomber, the F-86 Sabre jet fighter, the X-15 rocket plane, and the XB-70, as well as Apollo Command and Service...
. Although the program was put on indefinite hold before any actual designs were completed, it paved the way for the B-70
XB-70 Valkyrie
The North American Aviation XB-70 Valkyrie was the prototype version of the proposed B-70 nuclear-armed deep-penetration strategic bomber for the United States Air Force's Strategic Air Command...
program.
Background
Boeing Aircraft Corporation's MX-2145 Project with Rand Corporation that started in January 1954 explored what sort of aircraft would be needed to deliver the various nuclear weapons then under development. Providing for a long range and high payload were obvious requirements, but they also concluded that after bomb-release the plane would need supersonic speed to escape the weapon's critical blast-radius. Jet engineJet engine
A jet engine is a reaction engine that discharges a fast moving jet to generate thrust by jet propulsion and in accordance with Newton's laws of motion. This broad definition of jet engines includes turbojets, turbofans, rockets, ramjets, pulse jets...
s of the time had poor fuel efficiency
Fuel efficiency
Fuel efficiency is a form of thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier fuel into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is...
. An aircraft capable of carrying a reasonable bomb load to the Soviet Union
Soviet Union
The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....
from the continental United States had to carry a large fuel load (and thus be very large itself) due to the unrefueled range required.
The aviation industry had been examining this problem for some time. There was considerable interest in the use of nuclear powered aircraft in the bomber role from the mid-1940s. Nuclear engines in aircraft
Aircraft Nuclear Propulsion
The Aircraft Nuclear Propulsion program and the preceding Nuclear Energy for the Propulsion of Aircraft project worked to develop a nuclear propulsion system for aircraft. The United States Army Air Force initiated Project NEPA on May 28, 1946...
used the heat generated by a nuclear reactor
Nuclear reactor
A nuclear reactor is a device to initiate and control a sustained nuclear chain reaction. Most commonly they are used for generating electricity and for the propulsion of ships. Usually heat from nuclear fission is passed to a working fluid , which runs through turbines that power either ship's...
in place of jet fuel, giving it virtually unlimited cruising range. In addition to solving the range issue, these aircraft could be flown to holding areas away from the airbases and kept in the air for extended periods of time, making them immune to sneak attack. Accordingly, Boeing developed plans for a nuclear powered bomber equipped with afterburners that used chemical fuel. Lockheed
Lockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...
and Convair
Convair
Convair was an American aircraft manufacturing company which later expanded into rockets and spacecraft. The company was formed in 1943 by the merger of Vultee Aircraft and Consolidated Aircraft, and went on to produce a number of pioneering aircraft, such as the Convair B-36 bomber, and the F-102...
proposed similar designs.
Another possibility was the use of boron
Boron
Boron is the chemical element with atomic number 5 and the chemical symbol B. Boron is a metalloid. Because boron is not produced by stellar nucleosynthesis, it is a low-abundance element in both the solar system and the Earth's crust. However, boron is concentrated on Earth by the...
-enriched "zip fuel
Zip fuel
Zip fuel, also known as high energy fuel , is any member of a family of jet fuels containing additives in the form of hydro-boron compounds, or boranes. Zip fuels offered higher power density than conventional fuels, helping extend the range of jet aircraft, a major problem for the military...
s", which improved the energy density
Energy density
Energy density is a term used for the amount of energy stored in a given system or region of space per unit volume. Often only the useful or extractable energy is quantified, which is to say that chemically inaccessible energy such as rest mass energy is ignored...
of the fuel by about 40%. Various U.S. government agencies had been experimenting with zip fuels for some time, and they believed that once the problems were solved, zip fuel would become almost universal for high-speed aircraft. Although the advantages of a zip-fueled aircraft would not be as great as those of a nuclear powered one, it would offer a real performance increase and was a relatively straightforward development of existing engines and fuels.
Air Force studies
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 11000 nautical miles (20,372 km), capable of flying up to 1000 miles (1,609.3 km) at a speed greater than Mach 2 at altitudes greater than 60000 feet (18,288 m) with a 20000 lb (9,071.8 kg) payload, revising this to 25000 lb (11,339.8 kg) in GOR.82 later that month.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 miles (1,609.3 km) 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".
Aircraft Nuclear Propulsion
The Aircraft Nuclear Propulsion program and the preceding Nuclear Energy for the Propulsion of Aircraft project worked to develop a nuclear propulsion system for aircraft. The United States Army Air Force initiated Project NEPA on May 28, 1946...
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 fuel
Zip fuel
Zip fuel, also known as high energy fuel , is any member of a family of jet fuels containing additives in the form of hydro-boron compounds, or boranes. Zip fuels offered higher power density than conventional fuels, helping extend the range of jet aircraft, a major problem for the military...
s 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
F-104 Starfighter
The Lockheed F-104 Starfighter is a single-engine, high-performance, supersonic interceptor aircraft originally developed for the United States Air Force by Lockheed. One of the Century Series of aircraft, it served with the USAF from 1958 until 1969, and continued with Air National Guard units...
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
Curtis LeMay
Curtis Emerson LeMay was a general in the United States Air Force and the vice presidential running mate of American Independent Party candidate George Wallace in 1968....
was not enthusiastic about the design, claiming "Hell, this isn't an airplane, it's a three-ship formation." 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.