Feature 2 | AircrAft cArriers
EMALS launcher starts HCT-2 testing
Now beginning a new phase of land-based testing, the US Navy’s future
electromagnetic aircraft launch system (EMALS) is designed to provide
better control forces (both peak and transient dynamic), improved
reliability and maintainability, increased operational availability and
reduced operator and maintainer workload.
G
eneral Atomics recently received
the green light to commence full
power train testing of the motor
components for the EMALS destined for
the US Navy’s next generation of aircraft
carriers. This second phase of High
Cycle Testing (HCT-2), which includes
environmental qualification tests, will
enable system engineers to collect data
and gauge the operability of EMALS.
Designed to replace the existing C-13
steam catapults used on the current Nimitz
class aircraft carriers, EMALS is seen to
offer significant life-cycle cost benefits in
terms of less maintenance (using modular
electrical and electronic components not
subject to mechanical wear), reduced
crew workload and increased reliability.
The new technology is one of the key
research and development paths for the
CVN-21 aircraft carrier programme
(with EMALS launchers planned to enter
cVN 78, assigned the name Gerald R Ford, will be equipped with four eMALs launchers.
service aboard USS Gerald R Ford in the
(photo: Northrop Grumman Newport News)
2015 timeframe).
Aircraft operations and flight-deck
operability also stand to gain as precise inverter. The linear motor takes the average Atomics Aeronautical Systems together
launcher control offers the potential power from the inverter and releases it in a with Alion Science and Technology,
to reduce the wind over deck required short pulse, which accelerates the aircraft Kato Engineering, Foster-Miller, L3
for launch and will be less stressing on for launch. Communications – Applied Technologies
airframes. Furthermore, it offers the In April 2004, the US Naval Air Pulse Sciences, University of Texas, Center
flexibility for low-speed (‘soft’) launch Systems Command (NAVAIR) awarded for Electromechanics and STV.
of unmanned aerial vehicles/unmanned an industry team led by General Atomics EMALS consists of five major
combat air vehicles. Aircraft engine Electromagnetic Systems a US$145 million subsystems:
and inlet steam ingestion constraints System Development and Demonstration
•
Prime Power Interface: this interconnects
are eliminated, and the carrier’s overall (SDD) contract. This followed a four- with the ship’s electrical distribution
infrared signature is reduced. year programme definition and system and delivers power to drive the
risk-reduction phase, which included the energy storage generators;
Launch accelerator testing of full-scale EMALS equipment
•
Launch motor: the linear induction
The EMALS system uses a long linear – including energy storage and power launch motor is a compact, modular,
electric motor to accelerate aircraft over conversion systems – on a half-length integrated flight-deck structure that
the flight deck, employing rotational launcher installed at the Naval Air Warfare converts electrical current into the
energy storage alternators to supply Center’s Lakehurst site. electromagnetic forces to accelerate the
high-frequency power to the linear motor The EMALS team comprises General aircraft along the launch stroke. A simple
through a pulse-width-modulated (PWM) Atomics Electronic Systems and General moving shuttle interfaces with the aircraft
22 Warship Technology May 2009
p22-23-24_WT_May09.indd 22 16/04/2009 11:59:21
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