Merlin HM MK1 (formerly Merlin EH101) is an Anti-Submarine (ASW) variant of the EH101 helicopter. The first aircraft was delivered in December 1998, to begin the replacement of the ageing ASW Sea King (Mk6). The 44th and final aircraft was delivered in December 2002.
Designed in Western Europe, through a project which began in 1979 with EH Industries (the company formed by Agusta of Italy and GKN Westland in the UK), it is the largest collaborative helicopter project in history.
In 1991 the United Kingdom selected IBM-Aerospace Systems Integration Corporation (ASIC) (subsequently Loral-ASIC, now Lockheed Martin ASIC (LMA)) as prime contractor to complete Royal Navy development, integration of the Mission System and production of 44 aircraft.
Further progress was made on the programme through the award of the Collaborative Production Investment contract in March 1992 to EH Industries. Contracts were also awarded to Lockheed Martin ASIC for the Merlin Training System in July 1994, and the Merlin Support and Spares Availability System in July 1996.
The first Merlin test flight was on 6 December 1995. This was followed by the first mission system fitted Merlin Mk1 flight in January 1997 and Royal Navy intensive flight trials began on schedule in December 1998.
The Royal Navy operate the aircraft from four aircraft squadrons and single aircraft flights, with worldwide detachments from a range of ships including CVS, RFAs and Type 23 frigates. An eight aircraft training Squadron and full motion simulator is based at RNAS Culdrose in Cornwall. The aircraft was effectively employed on force protection duties during the Gulf War.
Work is currently underway to sustain the capability of the in-service Merlin Mk1 aircraft to its out of service date.
General characteristics / technical performance
The aircraft has a state-of-the-art, integrated mission system, which processes data from an extensive array of on-board sensors, giving Merlin an independent capability to search for, locate and attack submarine targets. It is this autonomous capability which makes Merlin unique among ASW helicopters.
The aircraft and its mission system are managed by two computer systems, linked by dual data buses. The cockpit is designed for operation by a single pilot, with the auto-pilot allowing for hands-off flight for most of the mission.
Normally flown by a crew of three - pilot, observer and aircrewman - Merlin is equipped with the Thales active "dunking" sonar which gives enhanced submarine detection ranges, and the GEC Marconi AQS 903A acoustic processor. All crew stations can access the management computers and operate the tactical displays. These are fed by the SELIX Blue Kestrel radar which possesses full 360-degree coverage and ability to Track-While-Scan surface contacts. It can also pass tactical information via a datalink to other participating units; a significant capability which has not been used by maritime helicopters before.
Based at RNAS Culdrose, Cornwall, Merlin is designed to operate in all weathers from the flight decks of both large and small ships (Invincible class aircraft carriers and Type 23 frigates). It is powered by three Rolls-Royce RTM 322 engines, is capable of speeds of up to 150 knots and has a range of 200 nautical miles. It can carry up to four homing torpedoes or depth charges, for use against threat submarines and can provide targeting information via datalink for the prosecution of surface threats. T
he Merlin retains all the secondary role capability of its predecessor, the Sea King, including loadlifting, casualty evacuation, troop carrying and search and rescue.
Physical characteristics
- All-up weight = 14,600kg
- Rotor diameter = 18.6m
- Length = 22.8m
- Width = 4.55m
- The anticipated service life of the aircraft is 35-40 years
Commercial aspects
The prime contractor is Lockheed Martin ASIC. The aircraft is a development of the military Naval version of the Anglo-Italian EH101 and has a large degree of commonality with the Medium Support Helicopter variant, the Merlin HC Mk3. The EH101 is manufactured by AgustaWestland which is an Italian / UK based company. The International Development Programme under which the EH101 was developed was an Anglo-Italian collaborative programme.
Each nation is currently procuring variants of the baseline helicopter. USA, Canada, Denmark, Portugal, Italy, India, Algeria, Japan and the Middle East have also procured variants of the EH101.