Gyundoan-Han GH-28 Ppulsoeori

GH-28 "Ppulsoeori"
The ASW and troop transport versions of the GH-28, with typical payloads.
Role	ASW helicopter (-N and -R)
National origin	Letnia/Menghe
Manufacturer	Gyundoan-Han Helicopter Factory
First flight	1979
Introduction	1981
Status	In service
Primary user	Menghean Navy
Produced	1980–present
Developed from	Kamov Ka-27

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

List of major variants of the GH-28. Note that variant "D" bears the insignia of the Menghean Red Manja Society.

GH-28G

Original troop transport and general utility version, which made its first flight in 1978.

GH-28N

Original anti-submarine warfare version from 1981. Features a nose-mounted sea search radar and a dipping sonar at the base of the tail, but no magnetic anomaly detector. The troop compartment is taken up by an electronics and instruments room, and the total crew is increased to six, with no space for passengers. Two external hardpoints are fitted; typically, one would carry a torpedo, and one would carry a rack of sonobuoys.

GH-28D

Dedicated search-and-rescue variant introduced in 1984. Generally similar to the GH-28G, it differs most visibly in the layout of the landing gear: the wheels are surrounded by inflatable floats, allowing the helicopter to land directly on the surface of the ocean. A small winch assembly over each sliding side door allows a rope or stretcher to be lowered into the water. No external hardpoints are fitted.

GH-28M

Airborne early warning variant with a large air- and surface-search radar mounted under the fuselage. In transit, the array is stored flush against the lower hull to reduce drag and allow landing. The array can be deployed when the helicopter is in a stable hovering position with calm to moderate winds. This function allows ship formations without land- or carrier-based fixed-wing AEW assets to more effectively track aircraft, missiles, and surface targets beyond the horizon. First flown in 1998.

GH-28SN

A new transport and utility model introduced in 2002. It sports new turbine engines designed by Taesan, resulting in increased power, reliability, and fuel efficiency. The avionics are all improved, including a surface search and navigation radar in the nose. No external hardpoints are fitted, but a power winch above each door allows faster deployment and recovery of personnel from a hovering position.

GH-28HJN

A search-and-rescue variant introduced in 2003. It is effectively a GH-28SN with remotely-aimed searchlights on either side of the nose, along with a few minor changes to the avionics and communications equipment, and stretcher mountings inside the passenger compartment.

GH-28M1

Designation for GH-28M AEW helicopters refitted to communicate with the datalink family used on the new generation of Menghean warships. All GH-28M helicopters in service were retrofitted to this standard in 2002-2004.

GH-28SN1

Designation for GH-28SN helicopters with braces for pintle-mounted weapons outside each sliding door. These can support GCh-77 or GCh-96 machine guns, automatic grenade launchers, or rotary machine guns. First seen in 2004.

GH-28DJN

An improved anti-submarine warfare variant, originally planned for introduction in 2001 but delayed until 2005. It was developed alongside the GH-28SN, and incorporates many of the same improvements, including the new Taesan engines for increased payload and speed. It features a new surface search radar in a redesigned nose cone, an electro-optical sight on top of the cockpit, and a towed magnetic anomaly detector which is stored under the tail when not in use. The rear fuselage section at the base of the tail is redesigned to accommodate a new type of dipping sonar. A total of 12 sonobuoys are carried in external boxes mounted on either side of the rear fuselage. The rear landing gear struts were redesigned to be further back, allowing the hardpoints to carry the longer YŎ-35/2 torpedo.

GH-28SGN

A "transport-gunship" (susong-gonggyŏk) version of the GH-28, introduced in 2006. It has two hardpoints per side, and uses vertical clamshell doors rather than sliding doors for access to the passenger compartment. The rapelling motors are retained. The pilot's position is equipped with a simple holographic sight, allowing the aiming of rocket pods and machine gun or cannon pods, but there are no provisions for controlling guided weapons.

GH-28SGD

An improved transport-gunship model, the GH-28SGD has redesigned pylons and flight controls, and an electro-optical sensor unit containing visual and infrared cameras and a laser designator. The copilot's station is equipped with a multi-function display linked to this camera, allowing the copilot (or weapon systems operator) to inspect targets or designate targets for laser-guided missiles.

GH-28DJD

An improved anti-submarine model introduced in 2015. It has the same surface search radar as the GH-28DJN, but a new electo-optical sensor under the left side of the nose, as well as streamlined hardpoints and rear landing gear units. A total of 20 sonobuoys are carried in a recessed grid array which fires them out of the right side of the rear fuselage. These combined changes reduce drag on the airframe, increasing its speed and range, and the dipping sonar is reportedly a newer model with greater range and sensitivity. Crew of 5.

GH-28GJN

An improved airborne early warning variant which entered service in 2016. Compared with the GH-28M, it features improved signal processing equipment. Externally, it can be identified by its forward landing gear, which are spaced more widely than on other models.

GH-28DJR

The latest major anti-submarine variant, the GH-28DJR features a cylindrical radome underneath the fuselage, flanked by redesigned forward landing gear. The nose contains a larger and more powerful electro-optical unit. The sonobuoy array is lengthened forward with an additional column of five tubes, bringing total capacity to 25, and the stub wings feature additional positions on the upper corners to mount air-to-air missile tubes (typically a YDG-38) to engage targets of opportunity or provide some defense against enemy fighters. Because the electronics on this model are more compact, there is also space inside the fuselage for four passengers (or seven if the sonar operator seats are also used) and mechanized rope lifts are installed. Machine gun pintles can also be mounted on the lower side of the clamshell doors while they are open. This gives the GH-28DJR more flexibility, allowing it to serve as a personnel transport or backup search-and-rescue unit rather than a dedicated anti-submarine platform.

Operators

• Menghe

Specifications (GH-28R1)

General characteristics

• Crew: 5 (pilot, copilot, and three sensor operators)
• Length: 12.77 m (41 ft 11 in)
• Rotor diameter: ()
• Height: 5.45 m (17 ft 10 in)
• Disc area: 2 × 15.8 m² (170 ft²)
• Empty weight: 7,650 kg (16,870 lb)
• Max. takeoff weight: 12,000 kg (26,500 lb)
• Powerplant: 2 × GH Type 04 turboshaft, 1,660 kW (2,230 hp) each

Performance

• Maximum speed: 260 km/h (140 knots, 161 mph)
• Range: 900 km (485 nautical miles, 560 miles)
• Service ceiling: 3,800 m (12,400 ft)

Armament

• Hardpoints: One pylon per side. Armament options for each hardpoint include:
  • 4 YGJ-48 anti-tank/anti-ship missiles
  • 8 YDCh-17 anti-tank missiles
  • 4 YDCh-72 anti-tank missiles
  • 1 GHB-8-20 J rocket pod with twenty 80mm rockets
  • 1 GHB-14-4 J rocket pod with four 140mm rockets
  • 1 P-500 series unguided bomb
  • 1 PR-500 series depth charge
  • 1 400mm homing torpedo
  • 1 23mm gun pod
• Additional over-wing mount for MANPADS missile tube.
  

Avionics

• Surface-search radar
• Dipping sonar
• Trailing magnetic anomaly detector
• 20 × sonobuoy in side ejector tube

See also

• Gyundoan-Han GH-26 Agŏ