v2.0.6 / 01 apr 09 / greg goebel / public domain
* As aerospace development programs have become more complicated and expensive over the last decades, countries have increasing pooled their resources to share program costs. Helicopters have been part of this trend, resulting in international programs to develop the AgustaWestland "EH101" and the NH Industries "NH90". These are state-of-the-art rotorcraft, intended for transport, maritime warfare, and search and rescue roles. This document provides a history and description of the EH101 and NH90.
* In the late 1970s, confronted with hundreds of Soviet attack submarines that threatened the sea lanes connecting Europe to America in time of war, the British Royal Navy (RN) and the Marina Militaire Italiane (MMI / Italian Navy) formulated a requirement for an advanced antisubmarine warfare (ASW) helicopter, to replace the Sikorsky-Agusta-Westland Sea King then in service for this role.
Westland of Britain's initial studies for a "Sea King Replacement (SKR)" were given the designation "WG.34". Basic requirements were for a helicopter that was more compact than the Sea King, but had a greater lift capability, and of course general improvements in operational performance and maintainability.
Discussions between Westland and Agusta of Italy on the SKR quickly resulted in the formation in June 1980 of a joint company named "European Helicopter (EH) Industries", with its headquarters in London, to develop the new helicopter, which was designated "EH101". Work was apportioned between the two parent companies to give them roughly equal shares without duplication.
As design studies progressed, it was decided that transport versions should be developed as well. Ultimately, a number of different EH101 variants were proposed:
A full-scale mockup of the EH101 was displayed at the Paris Air Show in 1985. A single ground test airframe called the "Iron Bird" and a total of nine flying preproduction prototypes ("PP"s) were built:
Initial production orders for the EH101 took place in 1991, with civil certification for the UK, Italy, and US following in 1994.
* The EH101 emerged as an attractive, sleek helicopter of generally conventional main / tail rotor configuration. It features a five-blade main rotor with paddles on the end of the blades, a four-blade tail rotor, and retractable undercarriage. It is powered by three turboshaft engines, with the engine type depending on the variant, with an auxiliary power unit (APU) for ground power and engine starting. The rotors are made of composite materials, while the fuselage is made of honeycomb lithium-aluminum alloy, with composite paneling. The tail boom folds forward, except in variants with a rear loading ramp.
The EH101 has an emergency floatation system using helium-inflated polyethylene-kevlar floats, as well as anti-icing features such as sideways-facing turbine inlets, provided because icing was a severe problem with the Sea King. The machine has a single-point pressure refueling system that allows it to be topped off in a few minutes.
* Development of the EH101 was protracted, for a number of reasons:
In July 2000, EH Industries was replaced by a full merger of Agusta and Westland, known simply as "AgustaWestland", and the EH101 is now properly referred to as the "AgustaWestland EH101".
* The two British EH101 variants are the Royal Navy's "Merlin HM.1" ASW helicopter and the Royal Air Force's (RAF) "Merlin HC.3" combat transport. Both are powered by three Rolls-Royce Turbomeca RTM322-01/8 or RTM332-02/8 turboshaft engines with 1,575 kW (2,100 SHP) for takeoff.
The Merlin HM.1 is an impressive rotorcraft, but its development wasn't
smooth. The procurement plan ran well over budget and was more than five
years behind schedule. However, aircrews were enthusiastic when they
received the new helicopter, praising it as "simple to handle, extremely
capable, and agile." They were very impressed with its avionics and
particularly its autopilot system. The Merlin's "Joint Tactical Information
Display System (JTIDS)" data link capability is a particular plus, allowing
operators to access "floods of data", and the helicopter is highly
maintainable.
AGUSTA-WESTLAND MERLIN HM.1:
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spec metric english
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fuselage length 19.5 meters 64 feet
length (with rotor) 22.8 meters 74 feet 9 inches
height (with rotor) 6.65 meters 21 feet 10 inches
main rotor diameter 18.6 meters 61 feet
empty weight: 10,500 kilograms 23,150 pounds
maximum speed: 309 KPH 192 MPH / 167 KT
cruise speed: 278 KPH 173 MPH / 150 KT
service ceiling: 4,575 meters 15,000 feet
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The Merlin HM.1 carries a pilot, copilot-observer, and two electronics
systems operators. The helicopter's electronics suite, integrated by
Lockheed Martin UK, provides formidable combat capabilities. The suite
includes an active Thomson Marconi dipping sonar that is so powerful that two
HM.1s can effectively monitor the entire English channel for submarine
activity. The HM.1 also carries a suite of various types of sonobuoys,
packed in two rotary stores stations in the rear of the cabin.
The Merlin carries a Blue Kestrel 5000 radar on the underside of the fuselage that provides 360-degree coverage and guidance capability for antiship missiles. An Orange Reaper (Racal Kestrel) electronic support measures (ESM) system uses six antennas to detect, locate, and identify about 2,000 different types of emitters. At least some of the Merlin fleet has been fitted with the Wescam MX-15 electro-optic imager turret.
Sensor data is processed, fused, and displayed by the Common Control Unit processor, which interfaces to the pilot, co-pilot, and to electronic systems operators in the cabin. The data is displayed overlaid on digital maps of the seabed. The HM.1 carries a set of radios fitted for encrypted communications. The only armament qualified so far for the Merlin HM.1 is the Marconi Stingray torpedo, with the helicopter carrying up to four. EH101 mockups were displayed with Exocet antiship missiles, but for the moment there is no interest in qualifying the Merlin to carry antiship missiles, that mission being performed by other platforms.
The Royal Navy ordered 44 Merlin HM.1s. The type is operated off Type 23 DUKE-class frigates, INVINCIBLE-class carriers, and other RN combat vessels. The first production aircraft flew on 6 December 1995, and the first fitted with operational avionics flew on 14 January 1997. A flight trials unit was formed as Number 700M Squadron on 1 December 1998. Number 824 Naval Air Squadron was formed for training in June 2000. The first frontline Merlin squadron, Number 814, was commissioned in late 2001, to be followed by Number 820 and Number 829 Squadron. The last of the 44 Merlin HM.1s was delivered in late 2002.
In 2006, a "Capability Sustainment Plus (CSP)" upgrade program was initiated for the Royal Navy's Merlin HM.1s, with the contract awarded to Lockheed-Martin. The upgrade will replace four rotor system control hydraulic actuators -- three for the main rotor, one for the tail rotor -- with low-maintenance electromechanical actuators. It will also add two BAE Systems fly-by-wire flight control computers, as well as fiber-optic links and two new electrical power generators. The upgrade will reduce weight by 40 kilograms (88 pounds), improve serviceability, and widen the EH101's flight envelope. 30 of the 44 rotorcraft purchased are to be upgraded, with an option for eight more upgrades; the first upgrades will reenter service in 2013.
* The RAF Merlin HC.3 transport can accommodate 30 troops, sixteen stretchers, or other loads of comparable weight. The first HC.3 flew on 24 December 1998. Initial operating capability was achieved in the summer of 2000, with the type going into service with RAF Number 28 and Number 72 Squadrons. The last of 22 Merlin HC.3s ordered was delivered in late 2002. In response to urgent operational requirements in Afghanistan and Iraq, in 2007 six more HC.3s were bought from the Danish Air Force -- see below -- only months after they had been delivered.
The Merlin HC.3 is less sophisticated than the HM.1, and has not suffered as much from development problems. The HC.3 differs from the HM.1 in having a rear-fuselage loading ramp, and of course does not have the elaborate ASW avionics fit of the HM.1.
However, the HC.3 is well-fitted for combat operations, with kit suggesting that it will be used for combat search and rescue (CSAR) or special operations missions. The HC.3 has a comprehensive electronics countermeasures (ECM) suite, including a new directed infrared countermeasures (DIRCM) with two turrets under the fuselage; the cockpit is designed to be compatible with night-vision goggles (NVGs); and a forward-looking infrared (FLIR) imager can be fitted in the nose. A fixed mid-air refueling probe can be installed as well, and there are pintles for mounting two light machine guns, with work underway for fit of a third machine gun. There is interest in supporting the more formidable Gatling minigun as well.
The type's first operational service was in deployment to Bosnia in 2003, leading to service in Iraq. Operational availability has been outstanding even given the tough Iraqi environment. The British, and other EH101 users, do report tail rotor hub cracking problems, but this problem is not generally regarded as a show-stopper, simply something maintenance crews need to keep an eye on. Work is underway for a redesigned tail rotor.
The British government is also considering a possible requirement for a Support Amphibious Battlefield Rotorcraft, which may lead to more EH101 orders from the UK.
* The three MMI variants of the EH101 are powered by three General Electric (GE) T700-GE-T6A engines with 1,530 kW (2,040 SHP) for takeoff. Italy has ordered sixteen EH101s, with the first flying on 6 December 1999, initial delivery in 2000, and final delivery in 2004. The Italians obtained three batches, with each batch to a different configuration:
AgustaWestland believes that Italy may order more EH101s, since the original requirement was for 36 aircraft.
* The Canadians were the next major buyer for the EH101, in the form of the "CH-149 Cormorant" AKA "AgustaWestland 520" search and rescue (SAR) variant. The original Canadian request, issued in 1993, was for 43 machines, including an ASW variant and a SAR variant, but this was cancelled when the Canadian Liberal Party came to power in 1993. However, the need for SAR helicopters for North Atlantic rescue operations remained outstanding, and 15 Cormorants were ordered in 1998 for the SAR role.
The Cormorant is based on the civil version of the EH101 as a cost-saving measure. It features mostly commercial off-the-shelf avionics, and has a rear loading ramp and a rescue winch. The first Cormorant took to the air on 31 May 2000 at the Agusta plant in Italy, and was flown across the Atlantic in early 2001 for service with the 442 Transport & Rescue Squadron at Comox in British Columbia. Five of the CH-149s were sent there in total, initially for operational training, while the other ten were split up between 413 Squadron at Greenwood, Nova Scotia, and 103 Squadron at Gander, Newfoundland.
The EH101 was also a contender for replacement of Canadian shipborne Sea King helicopters, which are just about ready to fall apart, with a potential order for 28 new aircraft. However, in the summer of 2004, Sikorsky won the contract with their comparable H-92 helicopter.
* Civilian models of the EH101 are powered by GE CT7-6 engines, the CT7 being commercial equivalent of the military T700 series, with 1,440 kW (1,920 SHP) for takeoff. There have been no sales of the Heliliner, which like the Merlin HC.3 can accommodate 30 passengers, but a single Series 510 was sold to the Tokyo Metropolitan Police Agency, with service entry in March 1999.
By mid-2000, AgustaWestland had orders and commitments for close to 100 EH101-series helicopters. Sales then went slow, compounded by a global economic slowdown that began at the end of 2000, but picked up with a number of new orders:
The minesweepers include kit for towing a minesweeping sled and have large rear-view mirrors to keep an eye on the sled. The machines are being assembled in Japan by Kawasaki Heavy Industries, and are being fitted with Japanese-built turboshaft engines. Initial deliveries were in 2006.
One of the more high-profile wins was in the "VXX" competition for the next US presidential helicopter, which sought a machine with better range, speed, and payload than the current Sikorsky "Presidential Hawk" machines. AgustaWestland joined forces with Lockheed Martin, already a partner in the Merlin HM.1 program, to offer the patriotically-named "US101" variant of the EH101.
The US101 was seen as something of a dark horse contender because the competition was the Sikorsky H-92. Sikorsky had long been a supplier of presidential helicopters, and the US has a long though not absolutely inflexible bias against buying foreign military hardware. Somewhat to everyone's surprise, the US101 won the award in early 2005, apparently because the H-92 was still in development while the US101 was more or less "off the shelf". It was assigned the designation of "VH-71 Kestrel".
The VH-71 will incorporate comforts for its passengers, communications systems to keep the commander-in-chief in touch, and an extensive self-defense suite as appropriate for an era of international terrorism. It will feature the latest GE CT7-8E turboshaft engines, providing 12% more power than the CT7-6. The CT7-8E fit was evaluated on a trials machine in the UK, with this machine also featuring improved avionics and advanced "British Experimental Rotor Program (BERP) IV" rotor blades, though it is unclear if these other advanced features will be included in the US101.
The VH-71 is to be in service by 2010 and a total of 23 machines will be obtained. This helped take quite a bit of the sting out of the loss of the Canadian Sea King replacement contract the summer before. It wasn't quite equivalent in terms of sales volume, but it was definitely a real win in terms of prestige, since a helicopter manufacturer couldn't have a much better advertisement than news videos of the American chief executive marching out of their machine, sitting there with rotors spinning and PRESIDENT OF THE UNITED STATES painted on the side.
The VH-71 will be the first helicopter of foreign design to be adopted by the American presidential fleet. News reports said that British Prime Minister Tony Blair and Italian Prime Minister Silvio Berlusconi had called US President George W. Bush to push for the deal, though program officials insisted they were not pressured by the White House to choose the US101. It is plausible that Misters Blair and Berlusconi simply wanted to make sure that the US101 was judged on a level basis with the S-92. If so, it clearly was; no doubt AgustaWestland executives felt justly pleased with themselves over the deal. Unfortunately, the program has suffered from delays and significant cost escalations, and is now in danger of cancellation, promising to reverse the gains made with the deal.
* The NH90 began life in the early 1980s as a European multinational development program for a new multi-purpose transport and naval helicopter, intended to replace the Bell UH-1 Huey, Aerospatiale Puma, Westland Lynx, and Sikorsky Sea King. The program was formally initiated in August 1992, with the participation of France, Germany, Italy, and the Netherlands.
The NH Industries consortium is headquartered in Aix-en-Provence in France, with the work done by AgustaWestland, Eurocopter France, Eurocopter Germany, and Fokker Aviation in the Netherlands. The first three manufacturers have a little over a 30% share each, while Fokker's share is about 5%. Norway became a "risk-sharing partner" of Eurocopter France in 1994. Portugal joined the group in June 2001, and has a 1.5% workshare.
The NH90 is of conventional appearance, with a main / tail rotor configuration and tricycle retractable landing gear. The default powerplants are two Rolls-Royce / Turbomeca RTM 322-01/9 turboshafts with a maximum rating of 1,575 kW (2,100 SHP) each, although the Italians have specified General Electric T700-T6E turboshafts with 1,530 kW (2,040 SHP) each, and other users may specify this alternate engine fit as well. Both types of engines have full authority digital engine control (FADEC). The power transmission system has a maximum rating of 2,560 kW (3,413 HP), so the engines will not be run at maximum power unless one fails. The NH90 is also fitted with an APU for self-starting and ground operation.
The main rotor system uses four composite blades with flared tips and a titanium hub. The tail rotor is of similar configuration. The machine's crashworthy airframe is built mostly of composite materials. There is a large sliding door on both sides of the machine, and crew exit doors on both sides of the cockpit.
The NH90 is designed for survivability, reliability, and ease of maintenance. It has an automatic fire detection and extinguisher system; crash resistant, self-sealing fuel tanks; a dual redundant hydraulic system; and dual redundant MIL-STD 1553B data buses. It has built-in monitoring and diagnostic systems. The NH90's glass cockpit has five 20 by 20 centimeter (8 by 8 inch) color flat panel displays. The NH90 can be optionally fitted with a FLIR turret in the nose, as well as defensive countermeasures aids.
* The NH90 is being offered in two different forms, the "NATO Frigate Helicopter (NFH)" and the "Tactical Transport Helicopter (TTH)".
The NFH is intended for ASW and maritime surface warfare, though it can be used for SAR and transport roles in a pinch. It has an automatic rotor and tail folding system, plus a combat avionics suite, including a 360 degree search radar in a drum under the fuselage, magnetic anomaly detector, dipping sonar or sonobuoys, electronic support measures system, and a "Link 11" datalink system. The NFH can carry up to 700 kilograms (1,545 pounds) of stores, including antiship missiles, homing torpedoes, and air-to-air missiles. Standard crew is pilot, copilot, and one or two systems operators. The pilot wears a Thales helmet-mounted sight system.
The TTH lacks the offensive avionics systems of the NFH, though it is fitted
with weather radar. It has infrared exhaust suppressors; armored crew seats;
a cable cutter; an NVG-compatible cockpit; and an optional rear loading ramp.
Standard crew is pilot and copilot, with a payload capacity of 20 troops, 12
stretchers, a light tactical vehicle, or 2,500 kilograms (5,500 pounds) of
cargo. The TTH can be fitted with defensive armament.
NH INDUSTRIES NH90 NFH:
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spec metric english
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main rotor diameter 16.3 meters 53 feet 6 inches
tail rotor diameter 3.2 meters 10 feet 6 inches
fuselage length 15.88 meters 52 feet 1 inch
footprint length 19.56 meters 64 feet 2 inches
height (tail rotor) 5.44 meters 17 feet 10 inches
empty weight 6,800 kilograms 14,995 pounds
max loaded weight 10,000 kilograms 22,000 pounds
max cruise speed 260 KPH 160 MPH / 140 KT
service ceiling 6,000 meters 19,700 feet
range 880 kilometers 550 MI / 475 NMI
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The TTH has a smaller empty weight of 5,400 kilograms (11,900 pounds)
and a higher cruise speed of 290 KPH (180 MPH).
Five NH90 prototypes were built:
Initial production delivery, of a TTH machine to Germany, was in May 2004, followed by a delivery of a TTH to Italy in September.
* A total of 363 NH90s are being built for the four original partner nations, including 270 TTHs and 93 NFHs. Italy has ordered 116, Germany 122, France 95, the Netherlands 20, and Portugal 10.
The NH90 won its first substantial foreign order in 2000. Sweden, Finland, Norway, and Denmark issued a joint request for a new "Nordic Standard Helicopter" and evaluated machines from most of the major helicopter manufacturers. The Danes dropped of the group and, as mentioned above, selected the EH101 since they felt they needed a larger machine for the SAR role, but the other three nations chose the NH90:
There was some worry about further orders, but as it turned out the NH90 was a fairly hot product:
Some difficulties have been encountered with the maritime variant of the NFH, mostly over qualifying the radar, and a fully-capable NFH is not expected to be available until late 2011 at earliest. Partially-capable NFH machines may be provided to some users as early as 2009 and then upgraded to full spec.
AgustaWestland's participation in the NH90 program means the company is competing with itself to a degree with the EH101, but the EH101 is a larger machine and fits into a somewhat different niche.
* Eurocopter is now introducing improvements to the NH90, the first being the "Hellas" laser-radar obstacle avoidance system. It is a sophisticated system, capable of identifying different classes of threats -- wires, poles, or trees -- and features a memory that allows it to display threats encountered previously but not within range of the laser system. Threat alerts are presented on cockpit multifunction displays and crew helmet sights. A number of NH90 users are upgrading their machines to the Hellas. EADS is working on a "Hellas-3D" follow-on, which features auxiliary millimeter-wave radar sensors and will be capable of providing situational awareness in "brownout" conditions, when the helicopter is trying to land in a cloud of dust and dirt.
The group is also considering development of a "Heavy Transport Helicopter (HTH)" as a follow-on to the NH90. Its primary focus would be replacement of the Sikorsky CH-53s now in German service, and would be introduced in 2018 at earliest. It is envisioned as having three engines, a seven-blade rotor, a fly-by-wire or "fly-by-light" control system, and protection from small-arms fire. Takeoff weight would be up to 40 tonnes (44 tons), and unrefueled range would be 1,200 kilometers (745 miles). Typical loads would be an infantry combat vehicle or 70 troops. The French and German governments have expressed interest in a machine along such lines.
* Sources include:
The EH101 and NH90 files in the FLUG-REVUE database were used as well.
* Revision history:
v1.0 / 01 nov 00 / gvg
v1.0.1 / 01 nov 01 / gvg / Minor cosmetic update.
v2.0.0 / 01 jun 02 / gvg / Added NH90 materials.
v2.0.1 / 01 jan 03 / gvg / Portugal EH101 order, Greek NH90 order.
v2.0.2 / 01 jul 04 / gvg / Minor cosmetic update.
v2.0.3 / 01 mar 05 / gvg / Update to mention VH101 award.
v2.0.4 / 01 mar 07 / gvg / Minor update.
v2.0.5 / 01 jun 07 / gvg / Minor update.
v2.0.6 / 01 apr 09 / gvg / Minor update.
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