If the CVF carriers are ever converted  to a "cat and trap" CV (aka CTOL) configuration, this will require the addition of a catapult launching system. 

The "Future Carrier Alliance"  propose that the CVF will be built to accommodate a potential electromagnetic catapult (EMCAT) backfit.  This will incur some additional costs at build, but will help 'future proof' the carrier design to accommodate new aircraft and air vehicles through its life - as is required by the MOD.

Compared with traditional steam catapults, EMCATs offer the prospect of significant life-cycle cost benefits (in terms of reduced maintenance and crew workload) and would also offer benefits for aircraft operations and flight-deck operability.   EMCAT's should increase launch performance and make significant reductions in installed weight, volume, and manning workload requirements. 

Early studies by DERA in the late 1990's indicated that a 90MW 300ft long linear motor EMCAT able to accelerate every 45 seconds a 100,000 lb. airplane to over 130 knots, or a lighter aircraft (such as UAV's) to 200 knots, would seem to be viable. 

The DPA announced in June 2000 a planning and test programme to examine whether EMCAT technology was a viable catapult option for CVF.  The solicitation for the technology demonstration stated: "The electromagnetic technology is considered to be available, but has never been built to the anticipated scale or integrated into a warship system.  [The] MoD wishes to develop and de-risk the technology in support of the FCBA programme, through the design, construction, integration and test of a system at a suitably representative scale.  ... The two-phase programme whilst reducing the technological risk aspects of the system, shall also provide unit production cost, through life cost and [availability, reliability and maintainability] information to allow objective comparisons to be made with alternative steam catapults."

The programme was never backed by BAE Systems and Thales who in October 2000 both expressed considerable concern at being tied down in their CVF proposals to commitments made by the DPA - indeed they preferred low risk and proven steam catapults for their CTOL design concepts.  However Alstom won the DPA study and the EMCAT technology programme continued and completed in March 2003, having de-risked demonstrated the core technologies needed for an EMCAT capable of launching manned aircraft from CVF.  Further development work was not pursued as with the selection of the STOVL but "adaptable" CVF design in September 2002 the programme was no longer considered necessary. 

Separately, across the Atlantic, the USN is actively planning for an Electromagnetic Aircraft Launch System (EMALS) to enter service aboard the projected CVN-21 class from 2014 - a comparable timeframe to CVF.

EMALS promises to deliver better performance and launch control that is tailored for a broader range of aircraft. It will accelerate aircraft weighing roughly 4500 to 45,000 kg to launch speeds of 100 to 370 km/h, with a controlled deftness that the inflexible, brute-force steam cats can't manage. Adjusting to the weight of the craft will mean less stress on the airframe. This will be especially crucial as the military adopts unmanned aircraft (UAV's) for surveillance as well as combat.

The heart of the USN EMALS is the 103-meter-long linear induction motor, which propels an armature, with the aircraft attached.  The linear motor of the EMALS is powered by energy from rotational storage devices that draw electric power from the ship's electrical distribution system. Initial EMALS design concepts included flywheels and pulse disk alternators, later eschewed in favor of more traditional systems that store energy in the rotors of generators, according to Richard Bushway, the U.S. Navy's EMALS program director.  Kinetic energy from the rotating system is converted into electric energy, and a solid-state power-conditioning system delivers a tremendous 2- to 3-second pulse of power to the stator.  The system must deliver the pulse as often as every 45 seconds to match the capability of the current steam catapult.

The EMALS system will use a 103 metre long linear electric motor to accelerate aircraft over the flight deck, employing rotational energy storage alternators to supply high-frequency power to the linear motor through a PWM inverter. The linear motor takes the average power from the inverter and releases it in a short pulse, which accelerates the aircraft for launch.

A closed-loop system, it constantly monitors itself, continuously adjusting the speed and power to create a launch profile tailored to each type of aircraft. Steam catapults are open-loop systems, with no sensors or feedback once the launch sequence is initiated.  In addition to allowing greater control flexibility, EMALS should eventually be half the size and weight of steam cat systems. Eliminating the maze of high-pressure, high-temperature steam pipes and valves will also lessen the risk to the crew during routine operations and battle.  It's also expected that with its electric and electronics subystems, EMALS could be serviced and maintained by an estimated 30 percent fewer crew members. Further, the EMALS is modular, so that components and subsystems can be swapped in and out both for maintenance and if,

Under parallel programme-definition and risk-reduction contracts awarded in December 1999, teams led by General Atomics and Northrop Grumman have each built full-scale, reduced length (c.50m) prototype systems, which were delivered to delivered in September 2003 to the U.S. Naval Air Systems Command site in Lakehurst, N.J. for testing and evaluation.  Following the hardware demonstrations, in April 2004 General Atomics was downselected and awarded a $145 million System Development and Demonstration (SDD) contract included the design, fabrication, delivery, integration, test and support of one full scale, full length, shipboard representative Electromagnetic Aircraft Launch System (EMALS) for NAVAIR Lakehurst, at the Naval Air Engineering Station Lakehurst, N.J.
 

It's expected that the first USN carrier to be fitted with EMALS catapults will be CVN-78, the lead ship of the new CVN-21 class, and expected to enter service in 2015.  She will fitted with four EMALS systems, each costing about US $26.5 million. 

The USN has held talks with the MoD over possible UK participation in the EMALS programme.  Apparently in 2004 the CVF platform design team asked General Atomics for technical information on their EMALS catapult so that appropriate provision could be made in the CVF design, but GA refused - in compliance with US laws.  The USN's EMALS programme and associated information is classified and the UK government had to negotiate with the US government to establish arrangements relating to the disclosure, transfer, and use of technical information. In late 2005 UK MOD sources disclosed that there had indeed been a recent joint study with the US Navy to examine the feasibility of fitting EMALS to CVF.   Given programme and risk issues, and projected equipment availability, EMALS catapults  would not be available for delivery to the UK prior to 2015.

Meanwhile, in April 2006 Converteam (as Alstom had been renamed) was awarded a further MoD Research Acquisition Organisation for the design, build and testing of an Electro-Magnetic Kinetic Integrated Technology (EMKIT) unmanned Air Vehicle (UAV)  technology demonstrator to demonstrate electromagnetic launch technology through the testing of a high-speed high acceleration demonstrator using advanced linear motor technology.  The system commissioned in December 2006 with land-based trials to commence in early 2007.  The demonstrator builds on the previous EMCAT project.  With two 3.2 MJ energy stores and a 14 metres launch length, it can launch UAV's of up to 500kg at a speed up to 50 m/sec.  The notional operation requirement is for a production  EMKIT system that will be able to launch UAV's such as the Hermes 180, Hermes 450, Eagle 1 and Predator A from ships as small as a frigate.

Arresting Gear

Like the catapults, it seems likely that any CTOL conversion of CVF will be fitted with US made arresting gear engines. 

The current USN standard is the Mark 7 Mod 3, however starting with the USS Ronald Reagan the USN is moving to a new three-wire Mark 7 Mod 4 arresting gear design (actually four arresting gear engines but with two of them interchangeable as the barricade engine).  The new system uses polycore cables designed to withstand more traps than steel cables and extra-large pulleys to reduce maintenance and man-hours, and provides the capability to land potentially larger and heavier aircraft.  It is hoped that the new design will reduce maintenance requirements by half by increasing the time interval between inspections and overhauls, in addition, the costs associated with replacing these high-wear components will be reduced.  Another benefit of this system will be that the arresting gear engines will be more accessible to flight line crews.

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