Rockwell International B-1 Bomber

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The Story and Description of the Rockwell International B-1 Bomber

The B-1 bomber has direct links to some of the greatest accomplishments in the aviation

industry. Consequently, this aircrafts interesting development and career has held a unique spot within

aeronautics. Its highly argued about where the B-1 starts due to alternatives proposed and forgone.

Early on the B-1 would be considered the best vehicle to replace the B-52, whose production had been

halted in 1962. The B-1 starts in 1955 with an initial requirement, known as GOR 82, to design a

Chemically-powered, strategic bombardment reconnaissance weapon system 110A/L.(book) Boeing

and North American Aviation were to conduct the initial studies. What

eventually evolved from GOR82 was the giant delta-wing (named

because of the shape of the wings) XB-70 Bomber. (Right)

North America was selected in 1957 to produce the advanced new system and seven years later

they reached the first flight. Of course a project always comes with naysayers, they argued that

strategic deterrence they were interested in achieving could be accomplished with munitions they

already have, intercontinental ballistic missiles and/or air launched missiles. And the fact is that the C-5

cargo-transport could carry the same payload of long range missiles to fulfill the strategic need, they

sought progression. Eventually, the B-70 lost momentum and was thrown out. The argument that the

B-70 was capable of more than what was thought lasted well into the 1980s.

Many other ideas for bomber aircraft were kicked around the 1960s. Radars weakest detection

is near the ground. The fact that the Soviets grounded a high altitude U.S. spy plane, the U2(next page),
http://en.wikipedia.org/wiki/Image:North_American_XB-70_above_runway_ECN-792.jpg


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made the aircraft designers of the U.S. conclude

that they needed to essentially design a plane that

had low altitude capabilities and able to reach high

speeds in this mode.

The two major studies in 1963, the AMP

(Advanced Man Penetrator) and the AMPSS (Advanced Man Penetrating Strategic Systems) provided the

way for the B-1. AMP called for a first-round design to meet four criteria: (1) all-subsonic, low altitude

(2) subsonic low-altitude with a high-altitude, high supersonic capability (3) subsonic low-altitude with a

high altitude, high supersonic capability (4) vertical/short take off and landing. The AMPSS honed in and

optimized the subsonic low-altitude aircraft with a high-altitude supersonic capability. In 1965 the

studies ended and later that year the well known AMSA (Advanced Man Strategic Aircraft) studies

emerged. This studys goal was to focus on propulsion, alternate armament loading, reliability, titanium

cost and maintainability.

It progressed quickly and the Air Force in 1967 wanted to submit a request to look for

contractors. Being the direct predecessor to the B-1, the AMSA led the Air Force to submit the request

in 1969. Seven months later Rockwell was to build the B-1 and GEs F101 engine was chosen as the

powerhouse. In October of 1971 the Rockwell was well on track by making the first full-scale B-1

bomber and in that same year it was approved. The first B-1 was called the B-1A.


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With the archetype flying by 1974, it was by 1977 Rockwell planned to have 241 bombers off the

line. But, in 1977 the program faced a major issue. It was cancelled. The B-1 faced scrutiny through

arguments which were raised and attested that the B-1 was, in fact, useless because the B-52 could

carry out missions which were specifically targeted by the B-1s engineers. During this time 4 prototypes

were still tested. These prototypes were important because they were used to provide information that

supported the idea that the B-1 was better than the B-52 in certain situations. After all the debates and

justifications were through, the B-1 made a comeback. The B-1A played an important part and provided

a sort of blueprint for a new B-1, the B-1B. Though the B-1A provided a general outline this didnt mean

it was a replica, in fact the B-1 brought many new innovations to the table. The biggest difference

between the aircraft would be the weight. The B-1B had a max weight of about 217,000kg; a lot of the

weight was because the plane had a higher fuel and payload capacity than the B-1A.

One of the noticeable aspects was the design that featured a blended wing and body. It has a swing-

wing design which provides means for high aerodynamic and structural efficiency. Not to be unnoticed

in todays military the configuration led to the design of

the infamous F-16 Fighting Falcon. The F-16 has a major

presence in the U.S. air force with fleet of over 1,200.

The wings spanned 41.67m in the forward position and
http://en.wikipedia.org/wiki/Image:B-1B_drawing.png


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23.84m when the aircraft morphed into its supersonic position. As you can see in the diagram the wings

werent perfectly straight when forward they were still slightly swept back. The B-1 has an airfoil which

was an exclusive design that was specifically made for the B-1. This special design enabled it to be

nearly perfectly efficient in a wide variety of conditions during takeoff and landing, subsonic cruise at

high lift, low-altitude penetration at low lift levels, and supersonic penetration at moderate lift.

With projected continual performances reaching Mach 2, the aerodynamic design became a

priority. The temperature the B-1B would reach floated around 421K. Because of the temperature the

engineers considered using titanium (around 40 percent) in the structure. The

metallic requirements were reduced due to the inability to detect and identify

targets at high speeds so close to the ground. With the adjustments it allowed the

engineers to use more aluminum which were for a variety of different reasons, mainly cost and ease of

fabrication. The B-1 not only had a requirement request for the structure, but also its engines. The

development of the engine had specific criteria: (1) unrefueled intercontinental range (2) Mach 2

performance (3) high thrust. General Electric was chosen as the builder and its F101 engine (above) was

the perfect match.

The development of the engine goes back to the late 1960s and again the AMSA studies. The

testing and write-off of the engine was in 1970. The original was a compact, two shafted, ducted,

afterburning turbofan. The full-length bypass duct of the engine carried the reduced air pressure


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around the outside of the engine core. The air then

went to fuel spray bars and flame holders adjacent to

the turbine exhaust stream as indicated in the figure on

the next page. As you can see, the fan blows low-

pressure air over the engine and as the high-pressure air

is ignited the air above the engine provides a sort of suction which increases the thrust.

The engine had a 2:1 bypass ratio a 2:1 bypass ratio is when the fan of the engine drives two

kilograms of air around the engine for every kilogram

that passes through the engine's core. The engine

produced a thrust at take off of about 75,619N and, by

adding afterburners, it significantly increased to

133,446N. The ISP of an afterburning high bypass

engine like the F-101-GE is represented in the chart to

the right. As you can see the fuel efficiency is one of

the best of to the jet propelled engines. This was

used to advantage of the B-1.

In 1984 the first B1-B was produced. The B-1Bs programs goal was to produce 100 aircraft

and equip the Strategic Air Command with 100 aircraft. This number was down from the production

numbers of the B-1As which had a quota of 241. The projected cost of the budget settled at around

20.5 billion dollars, or a little over $40 billion today. The Rockwell assembly building was enormous and

boasted over a million square feet of production possibilities. This was the home production site for all

100 aircraft.
http://en.wikipedia.org/wiki/Image:Turbofan_operation.pnghttp://upload.wikimedia.org/wikipedia/en/e/ef/Specific-impulse-kk-20050824.png


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The primary function of the B-1B was to be a long-range, multi-role, heavy bomber. This giant

44.5 meter long aircraft was powered by four General Electric F-101-GE-102 afterburning turbofan

engines. The B-1 stood at a height of 10.4 meters and weighed in at around 86,183 kilograms. The

maximum takeoff weight was 216,634 kilograms. At sea level the aircraft can travel upwards of 402m/s

or Mach 1.2 and has a service ceiling of more than 9,144 meters. All the while, the B-1B can harbor a

crew of four, aircraft commander, copilot, offensive systems officer and defensive systems officer while

completing these tasks. Just like other bombers, the B-1B, simply put, was just a mounting platform for

various weapons. It was considered such an asset due to its versatile system which carried a variety of

weapons. Included within that variety were conventional and nuclear bombs, and short range attack

and air-launched cruise missiles. This aircraft shows it versatility by being apt to be used in long-range

sea surveillance, anti-submarine patrol, and aerial mine-laying activities.

The B-1 has received much attention in aviation considering the records the aircraft has broken.

With 59 world records for speed, payload, distance and time-to-climb the B-1 made its mark in

aeronautics. The following chart from the United States Air Force shows the impact the B-1 had on the

industry:

Time-to-Climb Records for the C-1Q Weight

Category, Over 330,000lb at Altitudes

10,000ft 1 minute 59 seconds

20,000ft 2 minutes 39 seconds




Category, 170,000lb to 220,000lb at

Altitudes




40,000ft 5 minutes 1 second


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Category, 220,000lb to 330,000lb at

Altitudes


20,000ft 1 minute 55 seconds30,000ft 2 minutes 23 seconds


The production rate was approximately one aircraft per month at $200-million dollars plus. By

the time the 23rd aircraft was produced that rate had risen to one per week. After production

improvements were being designed and incorporated into elder versions of the B1-B. But, since the B-1

had significant time in the air it made way for avionic watchdogs of the government to seek and point

out issues the B-1 had. They claimed that the B-1 was capable of accomplishing only a few of its

intended missions against the Soviet air defenses and the cost estimates to fix the problems were

astronomical. Now, as it stands, there will be no more B-1Bs produced. But, theres good news for the

future, the B-2.

The acquisition of the B-2, in concert with the B1-B, ensures the Air Forces ability to provide

strategic deterrence into the 21st century. As it stands, the B-1Bs fleet consists of an active force of 51

aircraft, primary mission aircraft inventory of 72, 2 test vehicles; the Air National Guard has 18 primary

mission aircraft inventory (20 actual) and zero on reserve. The future doesnt look good for the B-1B,

but the fact that it has been such an integral part to the aeronautics industry, and that the trail it blazed

nearly forty-years ago will have an ever-present effect which will never be forgotten.


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http://en.wikipedia.org/wiki/Bypass_ratio(BYPASS ILLISTRATION)

http://www.af.mil/factsheets/factsheet.asp?fsID=81 (U.S. Air Force)

http://en.wikipedia.org/wiki/Specific_Impulse (ISP Illustration)

http://www.geae.com/engines/military/f101/index.html (PICTURE OF GE-F101)

http://en.wikipedia.org/wiki/Lockheed_U-2 (PICTURE of U-2 SPY PLANE)

http://en.wikipedia.org/wiki/B1B (WING ILLUSTRATION)

http://en.wikipedia.org/wiki/B1_bomber (REFERENCE)

http://inventors.about.com/library/inventors/blB_1B_Lancer.htm (REFERENCE)

The Illustrated Guide to Aerodynamics, H.C. Skip Smith; TAB Books: New York; 1992

-Used for Reference

The B-1 Bomber, William G. Holder; TAB Books: Blue Ridge Summit, PA; 1988

-Used for Reference
http://en.wikipedia.org/wiki/Bypass_ratiohttp://en.wikipedia.org/wiki/Bypass_ratiohttp://www.af.mil/factsheets/factsheet.asp?fsID=81http://www.af.mil/factsheets/factsheet.asp?fsID=81http://en.wikipedia.org/wiki/Specific_Impulsehttp://en.wikipedia.org/wiki/Specific_Impulsehttp://www.geae.com/engines/military/f101/index.htmlhttp://www.geae.com/engines/military/f101/index.htmlhttp://en.wikipedia.org/wiki/Lockheed_U-2http://en.wikipedia.org/wiki/Lockheed_U-2http://en.wikipedia.org/wiki/B1Bhttp://en.wikipedia.org/wiki/B1Bhttp://en.wikipedia.org/wiki/B1_bomberhttp://en.wikipedia.org/wiki/B1_bomberhttp://inventors.about.com/library/inventors/blB_1B_Lancer.htmhttp://inventors.about.com/library/inventors/blB_1B_Lancer.htmhttp://inventors.about.com/library/inventors/blB_1B_Lancer.htmhttp://en.wikipedia.org/wiki/B1_bomberhttp://en.wikipedia.org/wiki/B1Bhttp://en.wikipedia.org/wiki/Lockheed_U-2http://www.geae.com/engines/military/f101/index.htmlhttp://en.wikipedia.org/wiki/Specific_Impulsehttp://www.af.mil/factsheets/factsheet.asp?fsID=81http://en.wikipedia.org/wiki/Bypass_ratio

Rockwell International B-1 Bomber

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