EMALS/ AAG: Electro-Magnetic Launch & Recovery for Carriers

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EMALS and AAG delays and cost increases have hit a point where they’re creating problems for the new Ford Class carriers, driving up costs to $12.8 billion for the 1st ship, adding risk, and impairing initial capabilities.

Costs: Since 2008, EMALS-related costs for the first-of-class Gerald R. Ford [CVN 78] have risen by 133.7%, from $317.7 – $742.6 million. AAG costs have also spiked, though its 124.8% jump is only from $75 – $168.6 million. This is so despite the Navy’s 2010 firm fixed-price contracts to produce these systems for CVN 78. Even with cost caps, however, late delivery and testing means that changes have to be made to a partially-complete ship. EMALS configuration changes have already forced electrical, wiring, and other changes within the ship; and instead of just being hoisted into place, the Advanced Arresting Gear will now have to be installed in pieces via a hole cut in the flight deck. AAG continues to undergo redesigns, most recently to its energy-absorbing “water twister,” and limited EMALS testing with the delayed F-35C risks forcing further changes after the ship has been built. The Navy says that all future changes will take place within the components’ allotted space and weight, but GAO doesn’t think they can possibly know that.

Risk: Beyond redesign risks, the Navy needs to confront larger ship delivery risks. At present, EMALS isn’t scheduled for TRL 7 level maturity until FY 2014, with AAG to follow in FY 2015. The ship is due for delivery in FY 2016. Systems are already maturing so late that comprehensive testing must wait until the ship is at sea, so further schedule delays have nowhere else to go. Launch delays would mean delays to post-launch test programs, which are closely synced with ship delivery.

Capabilities: Once CVN 78 is built, EMALS and AAG’s reliability will continue to hamper operations. As of March 2013, both systems are far below where they’re supposed to be, with critical failures every 2-3 cycles. Since Initial Operational Test & Evaluation requires certain reliability levels between critical failures (MTBCF), continued problems could endanger the ship’s entry into service. GAO points out that the Navy’s “Duane” model for reliability growth doesn’t match their long-standing data, and even under optimistic planned growth levels, AAG isn’t supposed to hit the ~100 cycle MTBCF minimums before 2027. EMALS will take even longer, to 2032.

Unless and until they succeed, they’ll destroy the new carriers’ key 2007 promise of generating 25% more aircraft sorties per ship than the Nimitz Class. As things stand, even meeting the USS Enterprise’s OEF wartime record of 2,970 combat missions and a 99.1% sortie completion rate seems unlikely. Sources: GAO Report #GAO-13-396 | Virginian-Pilot , “The costs and doubts keep growing for carrier Ford”.


EMALS/ AAG: Electro-Magnetic Launch & Recovery for Carriers

 

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From Steam to Magnets: EMALS vs. Current Approaches


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.

EMALS’ problem is that it has become a potential bottleneck to the USA’s new carrier class. It opportunity is that it may become the savior of Britain’s new carrier class.

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.

Ford Class Enhancements

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.

Launches have begun, and the 2nd phase of EMALS aircraft compatibility testing is scheduled to begin in 2012. Engineers will continue reliability testing through 2013, then perform installation, checkout, and shipboard testing, with the goal of shipboard certification in 2015.

The related Advanced Arresting Gear (AAG) sub-program will replace the current Mk 7 hydraulic system used to provide the requisite combination of plane-slowing firmness and necessary flexibility to the carriers’ arresting wires. The winning AAG design replaces the mechanical hydraulic ram with rotary engines, using energy-absorbing water turbines and a large induction motor to provide 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.


EMALS was also set to play a pivotal role in the British CVF Queen Elizabeth Class, until the window of opportunity shut in 2012. The F-35B’s ability to take off and land with full air-to-air armament was already a matter of some concern in Britain before the 2010 strategic defense review, which moved the heavier F-35C from “Plan B” for British naval aviation, to the Royal Navy’s preferred choice.

An F-35C requires catapults, but the Queen Elizabeth Class carrier’s CODAG (COmbined Diesel And Gas) propulsion doesn’t produce steam as a byproduct, the way nuclear-powered carriers do. Instead, it produces a lot of electricity. Adding steam would require a huge redesign in the middle of construction, and raise costs to a point that would sink the program entirely. Instead, after commissioning some research of their own with British firms, they placed a formal request to buy EMALS.

By 2012, however, the Royal Navy had discovered that adding catapults to its new carrier design was much more difficult and expensive than BAE had led them to believe. In an embarrassing climb-down, the government retreated back to the F-35B STOVL (short Take-Off, Vertical Landing) fighter, and ended efforts to add catapults to its carriers.


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EMALS/ AAG: Electro-Magnetic Launch & Recovery for Carriers