Zhongbin Z.28

The Zhongbin Z.28 is a twin-engine,, multi-role, developed by the Zhongbin Aircraft Company. It serves as the primary all-weather, day-or-night assault transport of combat troops, supplies and equipment for the Imperial Kodeshi Naval Air Arm. The Imperial Kodeshi Navy also used the helicopter for mine-laying, antisubmarine warfare, combat support, and search and rescue (SAR). The Z.28 also serves a the Imperial Kodeshi Army's standard medium-lift utility helicopter. The Imperial Kodeshi Air Force also uses a small number of Z.28s predominantly in the SAR role.

Design and development
The program was started in the late 1950s during the later stages of the Great Kesh War and approved by the Guoist Government but issues surrounding the armistice and subsequent 1964 Xuanyi Restoration delayed the program and efforts and it would not be ready until the late 1960s. The first prototype first flew on December 3, 1967 and has performed flight testing up to 1972. It passed certification testing and a full-scale production of the aircraft, began with the type introduced to the Imperial Kodeshi Naval Air Arm. First delivered in began in April 5 1976, it is manufactured by the Zhongbin Aircraft Company in Malipo. The Zhongbin Z.28 was specifically developed to fulfil a growing demand for a heavy-lift helicopter in Kodeshia. The Z.28 debuted in December 1968 at the Malipo Airshow and the first flight outside Kodeshia was in Akiteiwa in the following August, with the first production flight being made in July 1975. The first Z.28s were built by Zhongbin Aircraft Company. After years of development, the Z.28 went into service with the Imperial Kodeshi Air Force, the Imperial Kodeshi Naval Air Arm, and the Imperial Kodeshi Army and for civil use. The Z.28’s design allows it to be adapted for a range of roles, from general aviation, utility, medical evacuation, and firefighting/smoke-breathing. The high speed and large internal capacity makes the Z.28 a useful combat aircraft. It can carry two howitzers and their ammunition, and five crew members along with its gear and fuel. In the anti-submarine warfare role, the Z.28 is used to transport sonar systems, torpedoes, and other equipment.

Origins
The initial design was presented by the Zhongbin Aircraft Company to the Imperial General Staff Department in December 1957. From 1961-63, the aircraft was studied by the National College of Aeronautics and National Kodeshi University. The Zhongbin Aircraft Company built the first mock-up models as part of rapid development program but by 1964 the Xuanyi Restoration set back the program. As an emergency measure, the company began work on the project without any official government funding and permission. By 1965, a team was assembled under the leadership of Yu Longyun, the head engineer on the program and by March the prototype had taken off. The first prototype performed a series of flights at Malipo airfield over the following months.

After the successful flight testing of the prototype, the first four helicopters were ordered in May 1966. The design was built primarily by the Zhongbin Aircraft Company at their factory in Malipo, with about one hundred workers and a design staff of about fifty people, and is now preserved by the National Air Force Museum of Kodeshia in Songhari.

Operational history
The initial production variant the Z.28YZ was medium-lift assault and cargo transport and SAR helicopter built for the Imperial Kodeshi Naval Air Arm. The Kodeshi Naval Air Arm began operating them from 1976. The type would adopted by the Imperial Kodeshi Army as the Z.28Y as a medium-lift utility transport helicopter for ground forces. The Z.28 has made its combat debut in operations against rebel forces in the northern Kodeshia in 1978 and has seen widespread service in all areas of the country since then. The 1978 operation was the first major helicopter operations since the end of the Great Kesh War, and it demonstrated that the helicopter was able to function effectively within the military's doctrine. Subsequent combat operations in this area were extensive and would continue for the next two decades. During these operations several thousand Z.28s would be deployed along with hundreds of attack helicopters and COIN aircraft to support operations in the area, of the over 460 Z.28 helicopters in the Kodeshi fleets, about 20 were the lost in combat or wartime operational accidents during the Insurgency Operations in northwest Kodeshia. A further 50 have been written off due to severe damage over their operational life.

The type would become the backbone of the Kodeshi Armed Forces medium-lift utility capability and numerous modernised variants would be produced including the adoption of (FBW) systems, composite materials, advanced new rotors and upgraded engines to lower maintenance requirements and reduce vibrations during flight. Most of the rest are currently flying in active service with the various branches of the Kodeshi armed services. The fleet of Z.28's is undergoing a refurbishment program with an expected completion date of 2020. Additionally newer variants are still being procured to replace older types in service.

Prototype Models

 * Zb.28YM-81
 * F = 原型; Yuánxíng ("Prototype"), M = 模型; Móxíng ("Model")
 * Company model number for basic prototype, one built.


 * Zb.28FM-81A
 * F = 发展; Fāzhǎn ("Development"), M = 模型; Móxíng ("Model")
 * Pre-production series powered by CAIC C6T-300A turboshaft engine, five built.

Production Models

 * Z.28TY
 * T = 突击; Tújí ("Assault"), Y = 运输; Yùnshū ("Transport")
 * Initial production variant. The medium-lift assault and cargo transport and SAR helicopter for the Kodeshi Naval Air Arm. Z.28YZ was powered initially by NAINCO WFZ-50J-2B engines rated at 1,800 shp (1,300 kW), but then replaced by the SHAECO SWZ-55A1 rated at 2,850 hp (2,130 kW). The Z.28YZ had a empty weight of 6,835 kg (15,070 lb), maximum gross weight of 14,515 kg (32,000 lb), allowing for a maximum payload around 12,425 lb (5,635 kg). The useful load was generally 5,411 kg (11,070 lb) with 12,247 kg (27,000 lb) being the standard loaded weight. It could carry howitzers and light scout vehicles can be loaded into the rear ramp and transported with crews. Initial delivery of the Z.28YZ to the Kodeshi Naval Air Arm was in 1976. A total of 80 were built.


 * Z.28SF
 * S = 扫雷; Sǎoléi ("Mine clearing"), F = 反潜战; Fǎnqián zhàn ("Antisubmarine Warfare")
 * Planned conversion of Z.28TYZs into minesweeping helicopters for the Imperial Kodeshi Navy, none converted.


 * Z.28Y
 * Y = 运输; Yùnshū ("Transport")
 * Medium-lift utility transport helicopter for the Imperial Kodeshi Army. Similar to the Z.28TYZ . 144 built.


 * Z.28TY1
 * T = 突击; Tújí ("Assault"),Y = 运输; Yùnshū ("Transport")
 * Improved variant medium-lift assault and cargo transport helicopters for the Kodeshi Naval Air Arm, The Z.28TGZ-1 principally featured more powerful engines and transmissions. It had NAINCO WFZ-50J-5C engines delivering 3,750 shp (2,800 kW), an upgraded maximum gross weight of 21,701 kg (47,842 lb), and a pitch stability augmentation system. 72 built.


 * Z.28S
 * S = 搜救; Sōujiù ("Search & Rescue")
 * Medium-lift search and rescue helicopters for the Imperial Kodeshi Air Force for search and rescue, 12 built.


 * Z.28DFS
 * D = 地雷层; Dìléi céng ("Mine layer"), F = 反潜战; Fǎnqián zhàn ("Antisubmarine Warfare"),S = 搜救; Sōujiù ("Search & Rescue")
 * Advanced mine-layer/antisubmarine warfare/search and rescue helicopter for the Kodeshi Naval Air Arm, 42 built.


 * Z.28TY2
 * T = 突击; Tújí ("Assault"),Y = 运输; Yùnshū ("Transport")
 * Improved heavy-lift variant, the Z.28TY-2 shares the same airframe as earlier models, the main difference being the adoption of more powerful engines. It had NAINCO WFZ-50J-7D engines delivering 2,927 kW (3,925 shp). The Z.28TY-2 can carry heavy payloads internally and up to 12,400 kg (27,337 lb). It was first introduced into service in 1993. In air assault operations, it often serves as the principal mover of the heavy howitzers, accompanying 30 rounds of ammunition, and an 11-man crew. The Z.28TY-2 also has advanced avionics, with forward-looking infrared (FLIR) imager, terrain-following radar (TFR) and airborne weather doppler-radar navigation system. Nearly all Kodeshi Z.28TY-1, Z.28TYs were conversions to this standard. 64 built.


 * Z.28TY3
 * T = 突击; Tújí ("Assault"),Y = 运输; Yùnshū ("Transport")
 * Deep Modernisation, upgrades include 3,400 kW (4,600 shp) NAINCO WFZ-50J-8D engines and the airframe featuring greater single-piece construction to lower maintenance requirements. This heavy-lift multi-purpose helicopter has been adopted by all branches of the Imperial Armed Forces of Kodeshia. New avionics include a digital flight by wire system and glass cockpit. The Z.28TY-3 has a payload of 9,817 kg (21,643 lb) with maximum take-off weight of 24,253 kg (53,469 lb). It features digital advanced flight-control system, providing an exact torque split between the rotors for greater efficiency. 48 built with a further 24 on order.

Civilian Models

 * Zb.28D
 * D = 多用途; Duō yòngtú ("Multi-purpose")
 * Commercial transport helicopter. The Zb.28D can be fitted out as an all-passenger, all-cargo, or cargo/passenger transport helicopter.


 * Zb.28K
 * K = 客机; Kèjī ("Airliner")
 * Commercial airline helicopter, with accommodation for 24 passengers.


 * Zb.28G
 * G = 贵宾; Guìbīn ("VIP")
 * Civilian VIP transport version, with accommodation for 10 passengers, equipped with a galley and toilet.


 * Zb.28S
 * S = 搜救; Sōujiù ("Search & Rescue")
 * Search and rescue version.

Operators
 Kodeshia
 * Imperial Kodeshi Air Force, operates 12 Z.28Ss with its search and rescue units.
 * Imperial Kodeshi Army, operates 119 Z.28Ys with the transport rotorcraft units.
 * Kodeshi Naval Air Arm, operates 131 consisting of 37 Z.28DFSs, 46 Z.28TY-2s and 48 Z.28TY-3s with the rotorcraft units.