Gyundoan-Han GH-26 Agŏ

The Gyundoan-Han GH-26 Agŏ is a Menghean attack helicopter with a secondary troop transport capability in certain models. Originally a licensed copy of the Reberiyan ShGv-5 with downgraded electronics, through a separate, parallel series of improvements and modernizations it has developed a number of major differences, most notably in the distinct location of the flexible 30mm cannon.

Licensing Agreement

In the late 1960s and early 1970s, the Democratic People's Republic of Menghe procured licenses for a number of military helicopters, mainly from Letnia. By 1973, the Menghean People's Army was expressing interest in a heavily armed helicopter gunship, motivated in large part by the ongoing proxy war in Dzhungestan.

Sim Jin-hwan initially favored a domestic design, in line with the Daesŭngri DS-5 and Songrim SR-7, but the Gyundoan-Han helicopter design bureau was apparently struggling to move beyond small, lightweight aircraft. After Letnia offered a gunship modification of the Mi-8, which the MPA found inadequate, Reberiya became an unlikely entrant into the competition by offering its ShGv-5. Six airframes were shipped to the DPRM for testing and evaluation in 1975, and after these impressed their operators, Menghe negotiated a production license in 1976. Mass production of the domestic Menghean variant, designated GH-26G, began the following year. Changes for Menghean production included the installation of new radio equipment and the redesign of the missile rails for the YDCh-10, a copy of the Letnian 9M14 Malyutka.

Minor upgrades and refits to the GH-26 appeared in the 1970s and 1980s, most of them adding compatibility with newer anti-tank guided missiles: the beam-riding YDCh-12 and YDCh-13. The IFF antennas were also replaced with domestic ones. A larger change came in 1998, with the GH-26D variant; in addition to support for the YDCh-17 missile, this added improved radio and ECM systems, and other electronics which had become available after Menghe's detente with the capitalist powers.

GH-26R

The result of design work undertaken in the early 2000s, the GH-26R was a comprehensive revision of the basic ShGv-5 airframe. Some regard it as the most unique of the ShGv-5's descendants. The changes were motivated by combat experience in the Polvokian Civil War, which revealed that the combined gunship-transport role was inferior to a pairing of dedicated transports and gunships. Shortly before introduction, the Ummayan Civil War brought additional lessons, and a licensing agreement allowed Menghe to produce the Glasic Brimstone missile as the YGJ-48, resulting in last-minute changes to the design.

The most distinct feature of the GH-26R, unique among Septentrion's helicopter gunships, was the placement of a 30mm 2A42 autocannon in a rotating turret centered under the fuselage. This required the installation of new landing gear to keep the fuselage higher off the ground when landed or taxiing. The ammunition feed, which had selectable high-explosive and armor-piercing belts, sat above the cannon in the rear of the troop compartment, along with expanded fuel tanks for greater range. About half of the original troop compartment remained, with four smaller fold-down seats relocated to the forward area. Standard doctrine held that these would be used to recover downed airmen, and otherwise left empty. On ferry flights the internal storage space could be used to carry personal belongings and supplies.

With a heavier autocannon now installed, the 23mm nose cannon was deleted, replaced by a larger electro-optical sight. The removal of the ammunition feed sections around the nose gave the gunner better downward visibility. The cockpit was given an armor-plated "dish" around its lower structure, protecting the crew from 23mm anti-aircraft fire over the frontal arc and complementing the armored glass of the canopy. The electronics, avionics, and ECM equipment were again upgraded, as were the cockpit displays, and a millimeter-wave doppler radar was installed on top of the rotor mast to improve ground-search capabilities.

A four-blade staggered tail rotor was installed in place of the three-blade one, and large air-mixing suppressors were installed over the turbine exhausts to reduce infrared signature and vent exhaust air into the rotor downwash and away from the skin of the airframe. The turbines themselves were replaced by newer models with higher peak output and greater reliability, mainly to compensate for the added fuel and ammunition weight.

Variant "R" was well-received by crews, though it came with its own problems. Even with new turbines, it lagged behind the GH-32 in speed and maneuverability. The relocated cannon caused less instability when firing at high off-center angles, as it was located almost directly under the rotor hub, but it could not fire ahead while the helicopter was moving forward due to poor upward traverse. Operational experience also revealed that on particularly rough landings the base of the autocannon could impact the ground, damaging the internal structure of the airframe.

Variants

GH-26G:

Original license-production variant, which entered service in 1977. Its ATGM armament consisted of manually guided YDCh-10 missiles.

GH-26N:

Variant with a laser guidance system to support more accurate YDCh-12 ATGMs. Also had minor changes to the IFF system. Introduced in 1981.

GH-26N1:

Upgrade kit for GH-26Ns, for compatibility with the newer YDCh-13. Introduced in 1985.

GH-26G1:

Upgrade kit for the GH-26G, to bring it to GH-26N1 standard.

GH-26N2:

Post-revolution upgrade of the GH-26N with improved electronics and avionics.

GH-26D:

The first major post-revolution variant, first seen in 1997. Avionics and electronics, including the gunner's camera, were substantially improved, and compatibility with early-model helmet-mounted sights was added. The wing hardpoints were updated to the new Army Aviation modular standard, and wired to carry the YDCh-17 ATGM or the YGG-5 air-to-air missile. Also introduced armored glass panels around the cockpit, though not around its lower section.

GN-26N3:

Upgrade kit for the GH-26N with most of the D model's features: new avionics, improved ECM, bulletproof glass, and compatibility with the YDCh-17.

GH-26SP:

A single GH-26G airframe rebuilt with a fenestron tail in the late 1990s, as a testbed for the GH-32 program.

GH-26R:

A major variant introduced in 2006. The nose-mounted 23mm cannon was replaced by a 30mm cannon centered under the fuselage, and the passenger compartment was converted into fuel and ammunition storage. Air mixing units were added over the exhaust vents to reduce the infrared signature. In addition to the D model's bulletproof glass, also added an armored tub around the lower half of the cockpit.

GH-26D1:

Upgrade kit for the GH-26D, introduced in 2008. Added compatibility with the YGJ-48 (Brimstone) missile and other new GH-26R armaments, as well as the -R's exhaust air mixers and defensive EW suite. The position of the cannon was not changed.

GH-26H:

Dedicated training airframe with the gun removed. All are conversions of "G" or "N" airframes, usually early-production ones. The external hardpoints are retained.

GH-26Jj:

Special upgrade package for service in Dzhungestan. Prominent dust filters are added ahead of the turbine intakes, and dust filtration elsewhere in the airframe is improved. Also carries all modifications up to -D1 standard.