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The SDY-Greadtóir 19 Cuaifeach Mark I Shipborne Helicopter is the result if a request for proposals by the SDF to replace the older Fuisce Utility Helicopters of the SDF in service since the late 70s. Developed and built by SDY's subsidiary Greadtóir Limited, which has modified helicopters according to custom specifications since the 90s, and is now, with the Cuaifeach, presenting their first own design.

The term cuaifeach means whirlwind.

Design

The SDY-Greadtóir 19 Cuaifeach Mark I Shipborne Helicopter is a relatively small sized shipborne helicopter with coaxial rotors. The fuselage has a length of 11.5 metres, a height of 5.2 metres and a diameter of the main rotors of 16 metres, although the main rotors can be folded for space-saving.

The Cuaifeach Helicopter has a crew of third, a pilot and a co-pilot, as well as a sonar operator. Up to 4.2 tons of freight can be loaded onboard the Cuaifeach Helicopter, the cabin being lined with folding chairs for up to 16 fully armed soldiers.

Due to its rugged design, the Cuaifeach Helicopter can be used in both tropical and arctic areas and can safely hover in storm force 5 due to a stable auto-pilot and an inertial guidance system connected to it. For operations in arctic areas, the rotor blades can be heated up.

Due to the rotor arrangement, the Cuaifeach Helicopter does not need a tail rotor, thus saving space and reducing the acoustic signature, eliminating the 'slapping'-noise. This rotor arrangement also allows for a more stable flight then single-rotor arrangements, reducing torque - for steering, the rotor blades are pitched, thus creating controlled torque.

For crew and passenger safety, the Cuaifeach Helicopter is equipped with chambers for survival gear and parachutes underneath the crew seats, while both sides of the airframe have containers for air cushions, which are automatically deployed as soon as the helicopter hits the water, thus enabling the crew and passengers to leave the aircraft as it is still above the surface and swim to the emergency inflatable dinghy.

Aiframe

The airframe is constructed as a semi-monocoque fuselage built of corrosion-resistant materials, lightly armoured to resist small arms fire. The cabin has space for pilot and copilot, while the sonar operator sits behind them. A twin-tail provides additional steering power.

The passenger compartment is separated from the crew compartment by a door, the passenger compartment featuring two wide entrances to either side. Provision to mount heavy machine guns are integrated into the sides for a door gunner on either side. Integrated into the fuselage are the rubber fuel tanks, self-sealing and fire-resistant.

The steering commands are transmitted by triple-redundant fly-by-wire systems based on modular architecture, including dual redundant digital databusses. Data about speed, heading and similar data is displayed digitally on the flight instrument displays, thus not relying on analogue dials and gauges. These displays can also support a pilot helmet with HUD-Capabilities.

The airframe also provides provisions to carry and deploy flares and chaffs for self-defence, two dispensers for each mounted on either side of the fuselage. Two stubby wings provide provisions to carry external fuel tanks, ammunition, like rocket pods or light anti-ship missiles, or external cargo pods on four hardpoints.

Engines

The engines of the Cuaifeach Helicopter are two Luas L-91 Mark II Turboshaft Engines, a new version of the capable engines which powered the Fuisce Utility Helicopters, providing 1700 horsepower each.

This engine, with a dry weight of 300 kilograms, is a free-turbine turboshaft engine with annual combustors, a single-stage turbine driving the 10 stage all-axial compressor. The engine features a double-redundant Full Authority Digital Engine Control System, or FADEC-System, which is a digital computer, the Engine Control Unit, with the accessories to control all aspects of the engine performance, thus providing maximum efficiency, both concerning power output and fuel efficiency, at any given condition. The L-91 consumes 300 grams of fuel per kilowatts and hour, achieving a maximum power-output of 1,267.7 kilowatts with an minimum air mass flow of 8.9 kilograms per second.

The engines themselves are relatively easy to maintain, although the maintenance of the concentric shaft and the accompanying gearboxes is a bit more complicated.

Sensors

The Cuaifeach Helicopter is equipped with a small radar underneath the cockpit, a magnetic anomaly detector in the tail, a dipping sonar in the back of the fuselage, and a dispenser for sonar buoys between the cockpit and the passengers cabin. The Cuaifeach Helicopter also equipped with a radar-warning receiver, telling the craft, when it is acquired by a radar.

Navigational data is provided by a GPS System, communications by a 16-channel digital communication set with a range of 500 kilometres. The radio is ECM-resistant, making interruptions to the radio traffic not impossible, but considerably harder.

SDY-Greadtóir 19 Cuaifeach Mark I Shipborne AWACS Helicopter

A special modification to the airframe is the SDY-Greadtóir 19 Cuaifeach Mark I Shipborne AWACS Helicopter, a helicopter equipped with a retractable landing gear and a large, foldable antenna of the early warning radar.

The compartment for passengers is taken up by the radar's crew, their processing systems, an Artio Battlescape Network Mark IV-L and the auxilliary power unit providing power for all of that. The radar, a Nuacht N-45 Mark II Planar Array Radar, can detect aircraft at a distance of 150 kilometres, surface vessels from, depending on their size, 100 to 250 kilometres and track up to 75 targets at the same time, relaying their data to a control node, for example a ship, via the aforementioned Artio Battlescape Network. An IFF-System is installed into the radar. If need should arise, the Cuaifeach AWACS Helicopter itself can act as the node, but we do not recommend that.

A helicopter equipped with these modifications can not be modified into any other role. However, the SDY-Greadtóir 19 Cuaifeach Mark I Shipborne AWACS Helicopter retains the capability to detect submarines, but does not have the provisions to fight them.

SDY-Greadtóir 19 Cuaifeach Mark I Shipborne Civilian Helicopter

Another modification is the SDY-Greadtóir 19 Cuaifeach Mark I Shipborne Civilian Helicopter, a demiliterized version of the airframe, lacking the armour, provisions to carry armament, the advanced sensors (like the sonar) and the countermeasures. In return, the SDY-Greadtóir 19 Cuaifeach Mark I Shipborne Civilian Helicopter is equipped with a sound-proof cabin and cockpit. The cabin can be modified to allow for a more luxurious feeling of flight or for the transport of freight or passengers as a liner.

A more specialized cargo lifter is currently in development.

History

During the 1940s and 1950, the SDF began with trials and subsequently the adoption of helicopters in place of floatplanes aboard its vessels. During that time, the seaplane tender SDFC Faoileán was rebuild as a helicopter carrier, signifying that change.

The change was rather fast, mainly due to the SDF having little in the ways of vessels capable of carrying floatplanes or subsequently helicopters. Over the decades, it became a design requirement for all new SDF-Navy vessels above a certain size to at least be able to support an exceedingly large helicopter.

That trend, increasing size of the helicopters for little to no gain, began to bother the planners of the SDF and with the starting development of the Sealgaire-class Helicopter Carrier, the SDF began to look for a replacement. SDY, developers of the Sealgaire-class, cooperated with several design offices to build the new shipborne helicopters of the SDF, one of which became the Cuaifeach.

With its first flight in late 2015, technical kinks of the Mark 0 and the initial testing aboard vessels of SDY's Yard Fleet being taken care of, the design proved promising. Mark I Prototypes provided relief and aid to Bolcán Island after the severe winter storm in late 2016, a short time later, in early 2017, the SDF ordered production runs.

With the planning of the Sealgaire-class Helicopter Carrier, the SDF also saw the need for an AWACS platform, deciding to adopt the Cuaifeach for that role, ordering the modification of the normal helicopter for that purpose, thus creating the SDY-Greadtóir 19 Cuaifeach Mark I Shipborne AWACS Helicopter.

First flight of that adaptation was in early 2017.

Other options for that role were specially constructed helicopter drones and helicopters, as well as VTOLs, but with logistical constrains in mind, the SDF decided for a modification of the Cuaifeach with its specially developed radar.

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