CVN 78 Gerald R Ford Class – US Navy CVN 21 Future Carrier Programme, USA

The US Navy's programme CVN 21 for the future generation aircraft carrier programme was previously known as the CVN(X) programme. In January 2007, The US Navy announced that the new class would be called the Gerald R Ford Class. The first two ships, Gerald R Ford (CVN 78) and CVN 79, will be commissioned in 2015 and 2019 and further ships of the class will enter service at intervals of five years.

CVN 78 will replace USS Enterprise (CVN 65) which entered service in 1961 and will approach the end of operational life by 2015. The total acquisition cost of the CVN 21 is expected to be $11.7bn.

The US Department of Defense awarded Northrop Grumman Newport News in Virginia a $107.6m contract in July 2003, $1.39bn contract in May 2004 and $559m to prepare for the carrier construction and to continue the design program on the ship's propulsion system.

The CVN 78 first steel was cut in August 2005. Full construction is expected to begin in 2008. Northrop Grumman was awarded a contract for the planning and design of the second carrier, CVN 79, in November 2006. Construction of CVN 79 is expected to begin in 2012.

CVN 21 DESIGN

The Gerald R Ford class carriers will be of about the same displacement, about 100,000t, as its predecessor the Nimitz class George H W Bush (CVN 77) but will have about 500 to 900 fewer crew members.

The manpower reduction was an additional key performance parameter added to the original four outlined in 2000 in the operational requirements document for the CVN 21 programme. It is estimated that the new carrier technologies will lead to a 30% reduction in maintenance requirement and further crew workload reduction will be achieved through higher levels of automation.

The other main differences in operational performance compared to the Nimitz Class are increased sortie rates at 160 sorties a day (compared to 140 a day), a weight and stability allowance over the 50-year operational service life of the ship, and increased (by approximately 150% ) electrical power generation and distribution to sustain the ship's advanced technology systems. Another key performance requirement is interoperability.

AIRCRAFT CARRIER HULL

All US Navy aircraft carriers since the 1960s have been built at Northrop Grumman Newport News. Northrop has extended its design and shipbuilding facilities with a new heavy plate workshop and burners, a new 5,000t thick plate press, covered assembly facilities and a new 1,050t-capacity crane.

Northrop is using a suite of computer-aided design tools for the CVN 21 programme, including a CATIA software suite for simulation of the production processes and a CAVE virtual environment package.

The hull design is very similar to that of the current Nimitz Class carriers and with the same number of decks. The island is smaller and moved further towards the aft of the ship.

The island has a composite mast with planar array radars, a volume search radar operating at S band and a multi-function radar at X band and also carries the stern-facing Joint Precision Approach and Landing System. (JPALS), which is based on local area differential Global Positioning System (GPS), rather than radar.

The aircraft carrier traditionally carries the flag officer and 70 staff of the carrier battle group. The flag bridge which has previously been accommodated in the carrier's island has been relocated to a lower deck in order to minimise the size of the island.

The ship's internal configuration and flight deck designs have been significantly changed. The lower decks incorporate a flexible rapidly reconfigurable layout allowing different layouts and installation of new equipment in command, planning and administration areas.

The requirement to build in weight and stability allowance will accommodate the added weight of new systems that will be installed over the 50-year operational life of the ship. The removal of one aircraft elevator unit and reducing the number of hangar bays from three to two have contributed to a reduction of the weight of the CVN 21.

WEAPONS

The carrier will be armed with the Raytheon Evolved Sea Sparrow Missile (ESSM), which defends against high-speed, highly manoeuvrable anti-ship missiles. The close-in weapon system is the Rolling Airframe Missile (RAM) from Raytheon and Ramsys GmbH.

AIRCRAFT

The carrier will be capable of carrying up to about 90 aircraft including the F-35 joint strike fighter, F/A-18E/F Super Hornet, E-2D Advanced Hawkeye, EA-18G, MH-60R/S helicopters and unmanned air vehicles and unmanned combat air vehicles.

The requirement for a higher sortie rate at 160 sorties a day with surges to a maximum of 220 sorties a day in times of crisis and intense air warfare activity, has led to design changes in the flight deck.

The flight deck has a relocated and smaller island, and there are three rather than four deck edge elevators. Deck extensions also increase the aircraft parking areas. The aircraft service stations are located near the 18 refuelling and rearming stops.

General Atomics has been awarded the contract to develop the EMALS electromagnetic aircraft launch system which uses a linear electromagnetic accelerator motor. EMALS demonstrators have been tested at the Naval Air Systems Command (NASC) Lakehurst test centre in New Jersey. It is planned that EMALS will replace the current C-13 steam catapults.

If successful, EMALS technology offers the potential benefit of finer aircraft acceleration control, which leads to lower stresses in the aircraft and pilots and provides a slower launch speed for unmanned air vehicles and allows a wider window of wind-over-deck speed required for the launch sequence.

The contract for the development of an advanced turbo-electric arrestor gear has been awarded to General Atomics. The electro-magnetic motor applies control to the synthetic arrestor cable to reduce the maximum tensions in the cable and reduce the peak load on the arrestor hook and on the aircraft fuselage.

AIRCRAFT WEAPONS

The flow of weapons to the aircraft stops on the flight deck has been upgraded to accommodate the higher sortie rates. The ship carries stores of missiles and cannon rounds for fighter aircraft, bombs and air-to-surface missiles for strike aircraft, and torpedoes and depth charges for anti-submarine warfare aircraft.

Weapons elevators take the weapons systems from the magazines to the weapons handling and weapons assembly areas on the 02-level deck (below the flight deck) and express weapons elevators are installed between the handling and assembly areas and the flight deck.

The two companies selected by Northrop Grumman to generate designs for the advanced weapons elevator are the Federal Equipment Company and Oldenburg Lakeshore Inc.

The deployment of all-up-rounds, which are larger, rather than traditional weapons requiring assembly will require double-height magazines and store rooms and will also impact on the level of need for weapons assembly facilities.

The US Navy outlined a requirement for a minimum 150% increase in the power-generation capacity for the CVN 21 carrier compared to the Nimitz Class carriers. The increased power capacity is needed for the four electro-magnetic aircraft launchers and for future systems such as directed energy weapons that might be feasible during the carrier's 50-year lifespan.

PROPULSION

Northrop Grumman is developing the advanced nuclear propulsion system and a zonal electrical power distribution system for the CVN 21.

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