The first launch of an aircraft by the U.S. Navy’s new Electro-Magnetic Aircraft Launch System could take place by mid-December, an event that would mark a major step ahead for a program with its full share of critics and doubters.
“The shot should take place within a couple of weeks,” said Rob Koon, a spokesman for Naval Air Systems Command (NAVAIR). Asked if the engineers were trying to make the launch before Christmas, Koon replied, “that’s what they’re hoping for.”
The Electro-magnetic Aircraft Launch System (EMALS) is a critical piece of technology that will be installed in the new Gerald R. Ford-class aircraft carriers, the first of which is now under construction. If the system isn’t ready in time, the Navy would have to revert to older steam catapults to launch aircraft from the ships, a move that would mean costly delays and redesigns.
An F/A-18E Super Hornet strike fighter is now being instrumented for the launch, Koon said. Test data is being analyzed for safety issues to obtain the necessary flight clearances.
The launch will take place at NAVAIR’s facility at the Naval Air Engineering Station Lakehurst, N.J., where the service and prime contractor General Atomics have built a full-scale test site replicating a shipboard installation, including major software and hardware components.
The development team began shooting test “dead-loads” from the system in the spring, Koon said. Since then, 722 dead-load launches have been made at speeds of up to 180 knots, the highest end-speed requirement for the system. The launch tests are part of the program’s system functional demonstration phase.
If the Super Hornet launch is successful, other types of carrier aircraft will be tested next year, including C-2 carrier-on-board-delivery planes and T-45 Goshawk jet trainers.
Koon said the EMALS program remains on track to deliver its first components to the new aircraft carrier in 2011.
The EMALS system would be the first new launch system since the Navy replaced hydraulic catapults with steam-powered systems in the 1950s. An electro-magnetic system has numerous advantages over steam. EMALS, which involves energizing a series of electro-magnets, is less stressful on aircraft and can launch a wider range of aircraft. The new system also would, theoretically, need less maintenance and cost less to operate.
The efficacy of the EMALS technology and particularly its test program has long been a question for the Navy, Congress and industry. The program — like nearly all technology development programs — has had its share of setbacks, but the service and General Atomics continue to insist the new system will be ready in time for installation on the Gerald R. Ford.
General Atomics made something of a statement of confidence on July 13, when it agreed to a $676.2 million fixed-price contract to produce the EMALS system and a new advanced arresting gear installation for the carrier.
|EMALS motor, HCT-1|
From Steam to Magnets: EMALS vs. Current Approach.
Current steam catapults use about 615 kg/ 1,350 pounds of steam for each aircraft launch, which is usually delivered by piping it from the nuclear reactor. Now add the required hydraulics and oils, the water required to brake the catapult, and associated pumps, motors, and control systems. The result is a large, heavy, maintenance-intensive system that operates without feedback control; and its sudden shocks shorten airframe lifespans for carrier-based aircraft.
To date, it has been the only option available. Hence its use on all full-size carriers.
EMALS (Electro-Magnetic Aircraft Launch System) uses an approach analogous to an electro-magnetic rail gun, in order to accelerate the shuttle that holds the aircraft. That approach provides a smoother launch, while offering up to 30% more launch energy potential to cope with heavier fighters. It also has far lower space and maintenance requirements, because it dispenses with most of the steam catapult’s piping, pumps, motors, control systems, etc. Ancillary benefits include the ability to embed diagnostic systems, for ease of maintenance with fewer personnel on board.
The challenge is scaling a relatively new technology to handle the required weights and power. EMALS motor generator weighs over 80,000 pounds, and is 13.5 feet long, almost 11 feet wide and almost 7 feet tall. It’s designed to deliver up to 60 megajoules of electricity, and 60 megawatts at its peak. In the 3 seconds it takes to launch a Navy aircraft, that amount of power could handle 12,000 homes. This motor generator is part of a suite of equipment called the Energy Storage Subsystem, which includes the motor generator, the generator control tower and the stored energy exciter power supply. The new Gerald R. Ford Class carriers will require 12 of each.
Because it’s such a big change, it’s a critical technology if the US Navy wishes to deliver its new carrier class on-time and on-budget, and fulfill the CVN-21 program’s cost-saving promises. If EMALS cannot deliver on time, or perform as advertised, the extensive redesign and additional costs involved in adding steam catapult equipment throughout the ship could easily rise to hundreds of millions of dollars.
The related Advanced Arresting Gear (AAG) sub-program will replace the current Mk 7 hydraulic system used to provide the carriers’ built-in system of arresting wires for carrier landings with the requisite combination of plane-slowing firmness and necessary flexibility. The winning AAG design replaces the mechanical hydraulic ram with rotary engines using proven energy-absorbing water turbines coupled to a large induction motor, providing fine control of the arresting forces. AAG is intended to allow successful landings with heavier aircraft, reduce manning and maintenance, and add capabilities like self-diagnosis and maintenance alerts. It will eventually be fitted to all existing Nimitz class aircraft carriers, as well as the new Gerald R. Ford class.
(click to view full)
EMALS may even prove critical to the future of the British CVF Queen Elizabeth Class, if the F-35B fighter proves unable to take off and land with full air-to-air armament. That’s a matter of some concern in Britain, which is looking into alternative landing approaches and sees the F-35C as its primary “Plan B” for naval aviation.
An F-35C would require catapults, however, and their new carrier’s CODAG (COmbined Diesel And Gas) propulsion doesn’t produce steam as a byproduct the way nuclear-powered carriers do. That threatens a significant redesign, and an accompanying rise in cost that could sink the program entirely. EMALS, on the other hand, would leverage the Queen Elizabeth Class’ design decision to become an all-electric ship, and require far less rework to install.
HMS Queen Elizabeth’s expected delivery date is now 2014-2015, and so the question is the same for Britain as it is for the USA: could a working, tested EMALS system be delivered in time?