Steam and hydraulics generally are considered a “maintenance
nightmare” on board Navy ships, particularly aircraft carriers.
These systems are labor intensive and costly to operate, officials
That is the thinking behind a $322 million, seven-year program
to replace the steam catapults that have launched carrier-based
aircraft for decades, with electromagnetic devices.
An electromagnetic aircraft launch system (EMALS) is planned for
the next-generation carrier, called CVNX-1, said Capt. Dudley Berthold,
Navy program executive officer. The Navy plans to develop CNVX-1
during the next decade. A follow-on carrier, the CVNX-2, potentially
could have, in addition to electric launch catapults, an electric
aircraft arresting system, said Berthold.
Steam catapults not only are expensive to maintain, but also limit
the types of aircraft that can be launched from carriers, explained
George Sulich, EMALS team leader at the Naval Air Systems Command.
EMALS is being designed so the Navy can launch a wide range of
manned and unmanned aircraft, from small drones, to large warplanes
such as the Joint Strike Fighter.
The program currently is in early development by two competing
contractors: General Atomics, in San Diego, and Northrop Grumman
Marine Systems, in Sunnyvale, Calif. This phase will end in late
2003. Next, will be a five-year engineering program to further develop
the technology, before it can be evaluated for future use in the
EMALS includes four basic components, explained Sulich. It has
an energy storage device, a power conditioning system, a linear
motor and a closed-loop control system.
The technology that the Navy asked contractors to use is called
linear induction motors, noted Michael Doyle, a Navy electrical
engineer. The linear induction motors make it possible for the vehicle
being launched to transverse the length of the catapult (about 300
feet) at speeds ranging from 55 knots to 200 knots, depending on
the size of the aircraft.
“Linear motors can be applied to anything that requires linear
motion,” said Doyle. The same technology could be used to
recover aircraft on the other end of the ship, or to power weapon
elevators. “We are pushing the state of the art in those underlying
technologies [such as] energy storage, power generation and power
conditioning,” he said.
The desire to simplify maintenance chores on the ship, however,
“is the biggest driver” in the project, said Sulich.
EMALS will perform automatic “health monitoring,” which
warns of system failures and keeps track of how many launches can
be made before maintenance work has to be done, he added.
Sulich estimated that the Navy could save up to 30 percent in labor
costs compared to steam catapults. That would generate enough savings,
over several years, to pay for the cost of developing EMALS, he
The Office of Naval Research, meanwhile, has funded a technology
demonstration for electromagnetic aircraft-arresting gear. “That
project could transition to an acquisition program for a linear
electromagnetic aircraft-recovery system,” said Sulich. A
decision is expected within the next year or so, after the Navy
completes an analysis of alternatives to replace the current arresting
One significant benefit of an electric catapult will be enhanced
precision, said David Ohst, business development manager at Northrop
Grumman. That will allow the Navy to expand the range of light and
heavy aircraft that can be launched from carriers, he said.
Michael R. Reed, director of business development at General Atomics,
noted that electric systems are not necessarily safer but are less
labor intensive and more “high-fidelity in the ability to
control the launch and the recovery.”
Neither contractor provided details on their proposals, for competitive
reasons. Both firms plan to compete in a future electromagnetic
arresting gear program, once the Navy makes a decision to fund it.