Gyundoan-Han GH-28 Ppulsoeori

The Gyundoan-Han GH-28 (Formal designation: 균도안-한 28호 직승기 / 균도안-恨 二八號 直升機, Gyundoan-Han ipal-ho Jiksŭnggi, "Gyundoan-Han No.28 Helicopter;" Short designation 균한-28 Gyuhan-ipal "GH-28"), also known by the nickname Ppulsoeori (뿔쇠오리, "crested murrelet"), is a utility helicopter family used by the Menghean Navy from the 1970s to the present day. It has been built in troop transport, anti-submarine warfare, and maritime search and rescue variants.

Design and development

In 1975, the Democratic People's Republic of Menghe purchased two Kamov Ka-27 helicopters from Letnia as competitors in a procurement search for the Menghean People's Navy. Though satisfied with most aspects of the design, MPN representatives requested that changes be made to suit their needs, resulting in substantial modifications to the body of the helicopter. While design work was underway, Gyundoan-Han negotiated a license agreement for the Ka-27's Klimov TV3-117 turbine engine and transmission, but did not negotiate a license for the Ka-27 itself. When the GH-28 was unveiled in 1978, its existence fed international debate over whether it had been illegally copied from the Ka-27 airframe, with Gyundoan-Han insisting that all aiframe parts apart from the powerplant and rotor set are of independent design and not subject to patent restrictions.

Like the Ka-27, the GH-28 uses a tandem rotor configuration, which eliminates the need for a tail rotor to counteract rotational torque. Once the helicopter has handed, service crews can fold the rotor blades back over the top of the fuselage, further reducing its storage space. A twin rotor also gives the GH-28 a relatively good power-to-weight ratio, allowing it to carry heavy sensor equipment (in its "N" variant) or a large cargo payload (in its "G" variant), and more stable handling in hover and descent, good for landing on a moving ship.

The GH-28 was originally ordered in two variants. The first, variant "G," was a dedicated troop transport and utility airframe, with a roomy passenger compartment and no dedicated ground-attack electronics apart from the pilot's holographic rocket sight. The second, variant "N," was a dedicated anti-submarine warfare platform, with a dipping sonar, sonobuoy rack, sea-search radar, and trailing magnetic anomaly detector. It also had room for two additional crew members who were tasked with monitoring the submarine-search electronics. Both helicopters retained external weapons pylons to carry rocket pods and homing torpedoes. Over the decades that followed, both received substantial upgrades and refits to make use of new weapons and electronics, and some new variants built around other roles were introduced.

Differences with Ka-27

Though the GH-28 is often described as a "clone" of the Kamov Ka-29, the two helicopters have a number of external differences due to Gyundoan and Han's modifications to the airframe. Notable external differences, useful for spotting and identification, include:

• The entire body is widened to match the cockpit, in contrast to the Ka-29, which becomes narrower near the hardpoint supports.
• The rudders and vertical stabilizers are more angular, and grow narrower from front to rear rather than rear to front.
• There is a centered, retractable front nosewheel, as opposed to the two non-retractable side nosewheels of the Ka-29.
• The rear landing gear sits under teardrop-shaped supports, and is retractable, with no link to the hardpoint supports.
• The door to the passenger compartment slides forward on rails, rather than opening in an up-down clamshell layout.
• The door to the pilot's compartment opens on a hinge rather than a rail.
• The window behind the pilot/copilot door windows is larger and slopes upward on the lower edge, somewhat resembling the windows on the Demirkan-Yŏng'an DY-11.
• On most versions, the external arms stores have one hardpoint per side rather than two, and they are about 33% shorter.
• The antennas and radomes under the tail boom are different, though they vary between models.
• The nose is slightly longer and rounder, and the cockpit slightly further forward.

Variants

GH-28G:

Original troop transport and general utility version.

GH-28N:

Original anti-submarine warfare version. Features a nose-mounted sea search radar, a dipping sonar at the base of the tail, and a trailing magnetic anomaly detector at the end of the tail. The troop compartment is taken up by an electronics and instruments room, and the total crew is increased to six. Unlike the Ka-27, it does not have an internal bay for sonobuoys; these are instead carried in a dispenser rack on one of the hardpoints.

GH-28D:

Dedicated search-and-rescue variant introduced in the 1980s. Generally similar to the GH-28G, it differs most visibly in the layout of the landing gear: the wheels are non-retractable, split one per side on the front, and are surrounded by inflatable floats, allowing the helicopter to land directly on the surface of the ocean. A small winch assembly over each door allows a rope or stretcher to be lowered into the water. The hardpoints are removed, but in their place the helicopter carries remote-controlled searchlights.

GH-28R:

Improved anti-submarine warfare version introduced in the 1990s. Features an entirely different sea-search radar in a new nose profile, as well as a new dipping sonar in the same compartment. The sliding doors of the crew compartment were removed entirely and replaced with a fixed, starboard-facing sonobuoy ejector system.

See also

• Gyundoan-Han GH-26 Agŏ