Building a Bomber

Early this century Henry Ford revolutionized the industrial world when he introduced the assembly line. Eight decades later, Northrop Grumman Corp. is relying on the same principles.

Only it’s not cheap cars quickly pieced together by unskilled laborers that roll off the end of the Northrop line in Palmdale.

Coming together are the B-2s, the sleek, radar-evading bombers built from hundreds of thousands of components that requires assembly so precise that tolerances are measured in thousandths of an inch.

Major components arrive from all over the country to be pieced together by highly-skilled workers who rely heavily on computers.

For the bomber to meet its charge of eluding enemy detection, every joint has to be seamless. This perfectly smooth finish is required over the entire bat-winged aircraft, which measures 69 feet in length, 17 feet in height and 172 feet from wingtip to wingtip.

Quantity

The original government order was for 132 B-2s. The end of the Cold War, budget constraints and other factors reduced that number to just 20. In March, funding was found to overhaul an early test model that otherwise would have been sent to a museum.

The 21st--and at this point last--B-2 is expected to roll off the assembly room floor next year. Over the next few years the other bombers will return to the Palmdale assembly plant for various systems upgrades, including electronics, weapons compatibility, air refueling and radar.

Cost

The government has already allocated $44.9 billion to the B-2 program, with $24 billion of that spent on research and development. In a 1994 proposal, Northrop said each additional B-2 the government orders beyond 21 would cost $750 million.

Capabilities

The B-2 offers some of the most prized features of a bomber: long range, large payload, low observability and ability to launch precision weapons systems.

* Range: 6,000 miles and with just one refueling can go 10,000 miles, allowing it to go virtually anywhere in the world.

* Payload capability: In excess of 40,000 pounds, with the ability to deliver a variety of conventional and nuclear weapons.

* Stealth capabilities: Combination of several factors, including the smoothness of the plane, its shape and tactics pilots use while flying it.

The Parts

The bomber’s components and who makes them

Northrop

Boeing

LTV

General Electric

Hughes

*

Outboard wing assembly

Aft/ center wing assembly

Gust load alleviation system

Fixed trailing edge

Engines

Inboard elevon

Mid elevon

Outboard elevon

Split rudder

Radar

Nose landing gear

Rotary launchers stack packs

Crew station assembly

Main landing grear

Intermediate wing assembly

Leading edge

Wingtips

Putting it Together

Assembly of a B-2 bomber takes about three years and is done at several workstations inside a 1- million- square- foot hanger in Palmdale. Just two bombers remain on the assembly floor and both are at the final station. Here is how the B-2 is assembled and the estimated time the craft spends at each station.

* Station #1: Cockpit, also called the crew station assembly, is built. Made of aluminum, this is the only section of the plane not built of composites. Time at station: Several months.

* Station #2: Cockpit is attached to wing assembly. Time at station: About five months.

* Station #3: Two intermediate wing assemblies are hand-attached using more than 10,000 fastemers/ Time at station: About five months.

* Station #4: Outboard wing assemblies, wingtips, main and nose landing gears and aircraft’s leading edge. Time at station: Five months.

* Pick-up station: Built into the assembly line is station where workers have 11 weeks to complete any tasks that should have been accomplished by this point in the manufacturing process or make any changes.

* Station #6: Flight controls, avionics, hydraulics and other systems installed. Aircraft’s 17,000 wire segments are tested. Time at station: 10 weeks.

* Station #7: Radar is installed. Remaining tests except those that require fuel are completed. Aircraft is painted and returned for installation of its four engines.

Note: Once the B-2 is moved out of the assembly plant a second time it is given a final coat of paint, then put through various acceptance tests before delivery to the Air Force.

Sources: Jim Hart, spokesman, and Tom Vice, customer requirements manager, both of Northrop Grumman Corp; Researched by SHARON MOESER/For The Times