Yu'an J.29

Kodeshia is its principal operator. The J.29 has been exported to various countries including Gardarike and Lestykhol. The J.29 was originally envisioned as primary long range air defence fighter aircraft of the Imperial Kodeshi Air Force. The aircraft design proved flexible enough that a later developed into a two-seat, dual-role fighter for all-weather, air-to-air and air-to-surface strike and electronic warfare derivatives, entered service in 1998 and remains the mainstay of the Imperial Kodeshi Air Force.

Development


The J.29 can trace its origins to the late Great Kesh War, when the Imperial Kodeshi Air Force was in desperate need of future tactical aircraft. In the mid 1950s the Imperial Kodeshi Air Force adopted a new low-cost tactical fighter design for short-range roles and close air support to replace several types fighters and various light bombers then in service. Several existing designs could fill this role; the design which would become known as the Yu'an J.21 which was a light fighter with a secondary attack capability. The next month, a report on light tactical aircraft suggested the Imperial Kodeshi Air Force purchase the J.21, and consider a new higher-performance aircraft to ensure its air superiority. This point was reinforced after the loss of many of its existing Dongfang J.52 air superiority aircraft to enemy forces. In 1957, research studies were begun on a next generation type air superiority fighter. These early studies envisioned a production run of 800 to 1,000 aircraft and stressed manoeuvrability over speed a departure from earlier jet designs which focused almost exclusively on high speed performance; it also stated that the aircraft would not be considered without some level of ground-attack capability. Later studies lowered the required performance from Mach 3.0 to 2.5 to lower costs and speed up production. An official requirements document for an air superiority fighter was finalised in 1955, and sent out as a request for proposals to 6 companies that same year. Meanwhile, the Yu'an J.21, quickly became the mainstay of the Imperial Kodeshi Air Force which limited some of the urgency of the new air superiority design as the J.21 offered a credible air-to-air capability.

The end of the Great Kesh War, led to a sudden but marked drop in defence spending and the next generation air superiority fighter proposals stalled until with the spending shifting towards the interceptor/strike fighter focused swing wing design Yu'an J.25 program. While air superiority was largely focused on improvements and further development to the J.21 type.

But during the mid-1960s, international developments such as the ZuB-12 Stervyatnik, which was designed as a high-speed, high-altitude interceptor aircraft, and made many performance trade-offs to excel in this role. Among these was the requirement for very high speed, over Mach 2.8. However, to observers, it appeared outwardly similar to an aircraft with high speed and a large wing offering high manoeuvrability, leading to serious concerns throughout defence establishment that it was superior to existing J.21 and possibly exceeding development of the J.25 then under development. Responding to these recent developments the next generation air superiority fighter program was restarted. Building on the combat experience from the Great Kesh War which missiles proved to be much less reliable than predicted, especially at close range. Combat pilots stressed that extra power and manoeuvrability were key aspects of a successful fighter design and these were more important than outright speed. A 1969 study proposed that the ideal design had a thrust-to-weight ratio near 1:1, a maximum speed further reduced to Mach 2.3, a weight of 40,000 pounds (18,000 kg), and a wing loading of 80 lb/ft². In 1970, a request for proposals was released to major aerospace companies. These requirements called for single-seat fighter having a maximum take-off weight of 40,000 pounds (18,000 kg) for the air-to-air role with a maximum speed of Mach 2.5 and a thrust-to-weight ratio of nearly 1:1 at mission weight. It also called for a twin-engine arrangement, as this was believed to respond to throttle changes more rapidly. However, details of the avionics were left largely undefined, as whether to build a larger aircraft with a powerful radar that could detect the enemy at longer ranges was not clear, or alternatively a smaller aircraft that would make detecting it more difficult for the enemy.

Design phase and prototype
Four companies responded with proposals. Following a down select, three companies were asked to provide further developments. In total, they developed some 600 design concepts. Typical designs featured variable-sweep wings, weight over 60,000 pounds (27,000 kg), included a top speed of Mach 2.7 and a thrust-to-weight ratio of 0.75. When the proposals were studied in 1958, the aircraft were roughly the size and weight of existing strike bombers were designs that could not be considered an air-superiority fighter. Tension between the Kodeshi Air force and the Central Military Commission led to a review, but in the end the project proceeded.

Three companies submitted proposals, with the Imperial Kodeshi Air Force eliminating Dongfang Aerospace Industries and awarding contracts to Yu'an Aircraft Industrial Corporation, Zhongbin Aircraft Company, and Nanbin Aircraft Corporation for the definition phase in 1970. The companies submitted technical proposals by 1971. For the first time, the designers had access to state of the aerodynamic research facilities, and with their resources, they started work on a full scale mockup, and began preliminary wing tunnel testing at the Experimental Test Station at Jianghua. The testing revealed that the Yu'an design offered the best balance of lift, drag, and control, while weighing less than other candidates. The Imperial Kodeshi Air Force announced the selection of Yu'an Aircraft Industrial Corporation in 1970. Yu'an began the detailed studies for the project. At first, the company concentrated on integrating the engine and other systems into one unit rather than two separate units. Thirteen prototypes were built, six for flight tests, one for wind tunnel validation, four for engine tests, and two for static ground configuration trials.

The Y.29 (Yu'an's 29th design), F = 原型; Yuánxíng ("Prototype"), M = 模型; Móxíng ("Model") was the designation for the prototypes, while wind tunnel testing and ground trials progressed in parallel with the flying prototypes. The first flying prototype (Y.29FM-8) was finished by 26 August 1974. It flew in 12 March 1975. The initial flight test programme included a number of flights from the ground, followed by short duration climbs, loops, rolls, stalls, stalling turns, inverted flight, after which the program entered into a long period of delays with the development of the Y.29 was marked by considerable problems, leading to repeated changes in the basic design to correct shortcomings identified during the early stages. The difficulties encountered in integrating the advanced flight control systems into the new airframe led to the serious delays and issues with the program. A fatal crash of one of the prototypes (Y.29FM-9) in 1976 led to major redesigns to improve the structural reliability of the entire series of prototypes and to incorporate lessons learned from this accident. Extensive redesigns followed to resolve the fundamental weaknesses discovered in the previous models.

A revised version of the Y.29FM-10, now designated the Y.29FM-X, made its first flight on 20 April 1977. The first flight was successful, and the new model proved to be highly manoeuvrable with excellent handling qualities. The new design also demonstrated superior performance in comparison to older fighters, and the combination of high climb rate, maximum altitude capability, long range, and good low speed characteristics made it suitable for a wide variety of roles. This was especially true in the role of interceptor fighter, where it could outperform all existing designs and was capable of engaging targets to a greater distance with better chances for success due to improved accuracy and faster reaction times in combat conditions. It was a great improvement over the previous design, but suffered some compromises in owing to the additional weight and complexity introduced in order to accommodate the new advanced avionics suite. Yu'an then turned its attention to designing the cockpit and conducting wind tunnel testing, which indicated that the fuselage needed strengthening to provide better control in crosswinds. This resulted in a redesign of the wing structure to add extra ribs along the upper surface of the wings. The new design allowed the wings to operate at higher angles of attack without causing structural failure. Further improvements in aerodynamics involved adding flaps along the trailing edge to increase lift. The revised version was tested, after which Yu'an declared itself ready to move into full-scale production.

Testing
The first combat-capable prototype (Y.29FM-X12) flew during 1979. Initial flights were commanded by test pilot Wei Dongliang. By 1978 there had been 32 test pilots who logged 2,600 hours flying the new type. Production models entered service with the Imperial Air Force on the 7 December 1979 with the designation J.29K (K = 空中优势; Kōngzhōng yōushì; "Air superiority"). The J.29K was declared ready and began operational test and evaluation. The initial batch of models were delivered to the 1st Test and Evaluation Squadron (TES) which was stood-up on that same year to carry out final evaluation and certification of the latest developments as the Operational Evaluation Unit for the type, allowing the J.29K to enter into mass production. The first combat trials took place in 1980, when a squadron performed mock dogfights against the Selengerian Air Force in real airspace. The tests showed that while it had good handling characteristics, the J.29K still required some refinement before being considered fit for front line duty, particularly regarding its targeting and weapons delivery systems. On the other hand, its ability to engage enemy aircraft at longer ranges than any of the contemporary air force fighters was deemed a major advantage over them.

Production and upgrades
Initially, the Kodeshi government had decided to purchase only 100 J-29s, but this figure increased to 300 aircraft in 1982. As of 1989, J-29s were operated by 16 squadrons of the Imperial Kodeshi Air Force. They purchased a total of 50 before deciding to delay the order because of concerns over costs and manufacturing difficulties. Yu'an continued working on the plane until 1981, when they reached a new agreement with the Kodeshi government, under which they would continue development and deliver another seven J-29s for completion and training purposes. These were completed in 1983. Subsequently, a second contract for an estimated 60 J-29s was awarded for a total cost of $2 billion (1982 prices). Production began in 1979, but was suspended in 1981 due to political and economic uncertainty and lack of funding. The J-29 was a technological breakthrough for the Kodeshi Air Force. It was designed as an interceptor fighter with a high speed, heavy armament and a large wing area for high manoeuvrability. The new proposal was to procure the whole fleet of J.29s. The Kodeshia government was concerned about the high cost and demanded cuts in both funding and the amount to be set aside for research and development. A compromise was reached whereby 30 J.29s should be ordered and 10 more built in 1984. The remaining 20 J-29s were to follow if and when funds became available.

In 1985, the Kodeshia government announced that the first five planes to be produced would undergo further testing and modifications before entering into full service in 1986. The main improvements planned for the J-29 included extending range, adding night vision equipment, increasing payload capacity, fitting a new engine and upgrading electronics systems. At this time it was also proposed to fit advanced avionics systems such as FLIR (forward looking infra red), radar warning receiver and other electronic countermeasures systems.

The total programme cost, as of 1988, was around US$42.7 billion (in current dollars). Which translated to a unit programme cost of approximately $33 million (1988). This is equivalent to just over half a million per plane (including pilot). This figure takes in account improved engines and avionics systems as well as modern weapons systems fitted to later models of J-29. In addition to the J.29K variant there was also the J.29J (J = 教練機; Jiàoliànjī; "Trainer") a two-seat training version used by the Kodeshia Air Training Academy to train pilots, although it retains full combat capability. By June 1982 a improvement programme was initiated in with the first production J.29Ks being delivered to the Air Force in May 1983. This variant added more powerful radar that introduced ground attack capabilities, increased thrust and had better performance compared with previous variants. The new type was designated the J.29D (D = 多用途; Duō yòngtú; "Multirole"). The added ground attack ability greatly enhanced the potency of the type, allowing them to become a fully multirole aircraft. This new capability was tested as J.29Ds participated in operations against rebel forces in the northern Kodeshia during the late 1980s civil war, becoming the only military aircraft of the era equipped with a weapon capable of delivering precision guided munitions, a laser designator/laser target acquisition system and a highly accurate and reliable air-to-ground targeting system, thus providing a key role in ending the conflict in the north.

After the civil war, the Kodeshia Air Force continued to expand the J.29 fleet, with a number of J.29Ks receiving updates to the J.29D standard as well as a few additional upgrades. These include upgraded radars with greater resolution and higher signal strength, incorporation of computerized navigation aids, such as inertial reference system for flight control system, digital autopilot system and automatic landing system with glide slope indicator. The newest model in the series, the JH.29D, is similar to the earlier J.29D but uses the twin seat configuration of the J.29J, and incorporates all the multirole ground attack and air superiority features of the earlier variant, but features a heavily strengthen structure, larger, more efficient engine, and other improvements to the aerodynamics to improve manoeuvrability and handling, particularly with heavy weapon loads. The new JH.29D has been adopted as the primary combat fighter for the Kodeshia Air Force, replacing older generation fighters.

In the 1990s, Kodeshia began proposing the integration of new weaponry, performance enhancements and additional capabilities to thier existing inventory, and has already begun integrating some new technologies into their current fleet of J.29s, with plans for upgrading the rest of their remaining J.29 fleet to incorporate these new technologies. By 1998 developing the next evolution of the JH.29, with a dedicated tactical reconnaissance and electronic warfare role, designated by Kodeshia as the JH.29DZ. Features the removal of the cannon and IRST systems replacing them with a dedicated electronic warfare systems, allowing for better use of the aircraft in air defense operations. It is also equipped with wingtip electronic warfare pods, to allow it to perform a variety of missions in the Electronic Warfare Theatre. It is intended to perform escort jamming as well as the traditional standoff jamming mission, using both conventional and nonconventional radar jammers. The new design will feature a strengthened fuselage and wings in order to withstand weapons loads up to 5,000 pounds, which would make it capable of carrying a variety of new guided missiles.

Beginning in 2009, 176 J.29Ks would be retrofitted with the latest generation of active electronically scanned array radars to improve their range and accuracy of fire, along with additional electronic warfare suites and anti-surface missiles to upgrade the fleet to J.29DX standard. The last batch of older J.29Ks were retired in September 2017, making way for delivery of new build J.29DXs from 2018 onwards with deliveries beginning in early 2019.

The J.29 had been scheduled to remain in service with the Imperial Kodeshi Air Force until 2045, when it is envisioned a successor under development by Yu'an the J.30 as a replacement for the Imperial Kodeshi Air Force as part of the Kodeshia's wider Future Combat Aircraft Programme will enter initial operational testing in 2030, eventually entering into serial production by 2050 with deliveries commencing by 2055, followed by deployment by 2025, with a projected combat lifespan of 25-35 years.

Design
The J.29 is an all-metal, construction. The platform features mid-mounted swept wing blended into the fuselage at the leading edge extensions and is essentially a cross between a swept wing and a cropped delta. There are swept tail planes and two vertical fins, mounted on booms outboard of the engines. Automatic slats are mounted on the leading edges of the wings; they are four-segment on early models and five-segment on some later variants. On the trailing edge, there are manoeuvring flaps and wingtip ailerons. It has retractable tricycle landing gear with twin mainwheels underneath each engine nacelle. It features lightweight construction with metal, primarily of aluminium and composite materials. The J.29K has hydraulic controls and a three-axis autopilot but, unlike the many of its later contemporaries, no fly-by-wire control system. It was originally intended to use an advanced fly-by-wire system but this was abandoned due to the high cost and complexity of installing such a system on a new design. The fatal accident with the prototype using these systems during flight testing was a major factor contributing towards this decision. It has a conventional cockpit, although it has been reworked to make room for a full set of avionics and communications equipment.

Nonetheless, it is very agile, with excellent instantaneous and sustained turn performance, high-alpha capability, and a general resistance to spins. The aircraft is capable of withstanding up to 9 g (88 m/s²) manoeuvres. The controls have "soft" limiters to prevent the pilot from exceeding g and alpha limits, but the limiters can be disabled manually. The hydraulics and trim were designed to be easily repaired in case of damage and often does not require any maintenance other than routine oil changes and filters throughout the career of a single airframe. However from the J.29DX the mechanical flight controls replaced by a system (FBWS) to reduce the weight and increase the reliability of the original version. The FBW allows the pilot to continually monitor the controls and automatically compensate for errors. The FBWS is made of a combination of electric motors, servos and software to correct a lot of potential mistakes. Additionally a full glass cockpits was installed to provide better visibility to the pilots in low light conditions as well as a large display screen to show important information to the crew. The airframe is extremely robust and has a low-drag configuration, enabling great endurance at supersonic speeds. It has been designed to carry a wide variety of weapons, including unguided bombs, rockets, air-to-air missiles, surface to air and anti-radiation missiles, cluster munitions, jammers, ECCM, ECWS and electronic countermeasures.

Avionics
According to Yu'an Aircraft Industrial Corporation officials the J.29 uses a multi-mode fire-control radar designed in Kodeshia. The Nangong N-25J/HKL-3M6 fire control system which includes the look-down/shoot-down coherent pulse-Doppler radar has a mechanically scanned planar array antenna and is capable of tracking 10 targets. Of the 10 targets tracked, 2 can be engaged simultaneously with semi-active radar homing missiles or 4 can be engaged with active radar homing missiles. The system also has a medium range air to ground missile guidance system using both infrared seeker and radio frequency seekers to guide anti-aircraft missiles and bombs. The system also supports synthetic aperture radars for long distance targeting. It also has a navigation system incorporating inertial navigation aided by GPS and GLOBAL Positioning System receivers. It also has an electronic warfare suite, chaff dispensers, ECM devices and jammer suites. The system has a computerized maintenance program for diagnostics and repair, and the entire system has been integrated into a single unit to minimize time spent on field repairs. The Nangong N-25J/HKL-3M6 radar was not a new design, but rather a development of the architecture of the original N-25J/HKL radar used in the first generation of the J.25.

During the initial design specification period in the mid-1970s, Nangong Electronic Systems Limited was tasked with producing a modern radar for the J.29. To speed development, Nangong based its new design on work undertaken on the experimental radar program. Accordingly, the N-25J/HKL-3M6 was originally intended to have a flat planar array antenna and full digital signal processing, for a detection and tracking range of at least 100 km against a fighter-sized target. Prototype testing revealed, however, that these features would require too much power and could not be produced within the required timeframe and still fit within the J.29's nose. Rather than design a new radar, Nangong reverted to a version of the J.25's twisted-polarization cassegrain antenna and traditional analog signal processors, coupled with a new digital computer to save time and cost. This was to ensure that the new radar met all specifications and that it was backward compatible with existing systems. Because of this, a number of changes were made to accommodate integration, such as the use of more powerful computers, redesigned antennas, new software, more sensitive sensors, and a new subsystem to provide high-altitude performance, among others. The new 3M6 version does, though, offer a better probability of intercept and higher accuracy than earlier versions, due to improvements in software and hardware technology as well as greater automation and integration of subsystems. For later variants such as the J.29DX, the nose cone is modified to accommodate an active phased array airborne radar (AESA) radar.

The KONSAI K-32J/DSZL AESA radar features the same basic architecture as the KM-31, but uses advanced ASROC (Advanced Synthetic Aperture Radar) techniques to allow it to automatically scan the sky, detecting any aircraft in the area while providing data fusion capabilities. This provides a huge leap in search capability compared with the older N-25/HKL-3M6 radars. It is capable of simultaneously searching and near instantaneous track updates. It can operate in conjunction with other types of radars, allowing enhanced operational capabilities. The KONSAI K-32J/DSZL has three modes: Airborne mode where it is used as a primary sensor, Ground attack mode, and Mobile TACTICAL AIR surveillance (MTAS) mode. The system is able to track up to 16 targets at once while supporting simultaneous engagements against those same targets. It is equipped with a laser designator for use in conjunction with air to surface munitions to allow direct hits on designated targets. It also has an IFF transponder to identify friendly aircraft to avoid mid-flight collisions and a data link to exchange tactical information and updates with other allied units and command stations. It also has an ECCM suite to detect and counter enemy jammers. Additionally the J.29 is equipped with the Taishi TQ-HSG infrared search and track (IRST) system for improved detection. When used with the radar in an air-to-air role, it functions as an infrared search and track system, providing passive target detection and tracking in the IR band. It is designed for use at night when there is little or no visible light to visually acquire targets. The system can detect variations in temperature at a long range. It also provides a navigation and landing aid.

The CAIC CJ-3 tactical data link system provides a digital communications link between fighter aircraft to enable real time transmission and reception of mission related information and orders from ground control. The system supports both synchronous and asynchronous operation, and is available in either single channel or dual channels configurations depending on the required bandwidth. The Optimates Identification friend or foe (IFF) allows the J.29 to distinguish friend from foe by measuring radio frequency emissions of friendly and hostile emitters. It has two operating frequencies, one for transmitting and another for receiving. It can be configured in a number of modes to determine if a signal is friend or foe based on the modulation type of a received signal and the strength of a transmitted signal.

The system has a modular design, with all major components being interchangeable and easily removable to facilitate maintenance. It is typically mounted directly onto the underside of the fuselage, and has provisions to mount additional equipment modules below its main instrumentation panel. The Nangong Electronic Systems Limited Electronic Warfare & Situational Awareness System and Multi-Spectral Targeting system are optional systems for enhancing the performance of the J.29.

The Nangong Electronic Systems Ltd (NES) Multispectral Targeting System is a sophisticated multi-mode electronic warfare and situational awareness system for detecting, locating, identifying, classifying and engaging airborne threats. It uses four independent sensors. The first sensor is a passive infrared search and track radar providing target detection. The second is a low resolution electro-optical imaging camera for identification purposes. A laser range finder measures the distance to targets beyond visual range. The KONSAI Electro-Optical Distributed Aperture System (EODAS) is a high resolution optical targeting system used to provide accurate line of sight guidance for weapons such as laser guided bombs. It is also capable of tracking multiple moving objects simultaneously, and is integrated into J.29s main computer to allow a pilot to select any desired target and designate it as "friend" or "foe". An important feature of this system is that it does not rely solely upon visual imagery acquired by the EO imager, but rather integrates this with other sources of intelligence data such as IFF and IRST to make a comprehensive picture of the battlefield situation.

The KONSAI Electro-Optical Targeting System (EOTS) is another option that is compatible with the existing NES Laser Range Finder to extend the effective firing envelope of a weapon to include attacking ground targets as well as air targets. The KONSAI helmet mounted display is new feature of this system and is designed to interface with the J.29 flight instruments so that it appears as a secondary monitor to the primary cockpit LCD screen. It is primarily intended as a replacement for the older HUD systems and incorporates features such as head up displays, terrain avoidance warning lights, and night vision capability. It allows the pilot to use the Helmet Mounted Display to provide better situational awareness in flight, as well as increasing his ability to work with a co-pilot during a mission. It is also possible for the system to be configured to provide the pilot to cue weapons systems, to the direction their head is pointing allowing targeting and accuracy. This enables a much faster response time when a threat is detected. Combined with new high off-boresight missiles provides pilots with the ability to fire at a target and maintain visual while doing so instead of having to wait until they can acquire a lock before launching.

Engines
The J.29 has two widely spaced Aero Engine Corporation of Shangyu (AECS) A/WS-100H low-bypass turbofan engines, each rated at 76.4 kN (17,175 lbf) dry and 109.8 kN (17,175 lbf) in afterburner. The initial engine choice was Zhongbin Zb.130s, a variant of the original WS model, however, due to concerns over reliability, the Zhongbin engine was replaced by the newer A/WS-100H. The new engines were produced in a joint venture between the Yu'an Aircraft Industrial Corporation and Aero Engine Corporation of Shangyu, all being built at the main facilities in Shangyu. The basic design of the A/WS-100H is an engine with a 2 spool, axial compressor with one stage for pressure recovery and four stages for compression, three combustion chambers per cylinder, a single fuel injector for each chamber, a dual ignition spark plug for each chamber. It has a variable bypass ratio and uses aerodynamic cooling fans to extract heat from the exhaust gases. The fan blades rotate at over 1,000 rpm, producing very efficient thrust at cruise speeds, even at altitudes greater than 50 km. The maintenance requirements for these engines is quite minimal as there are only five moving parts in a typical engine, thus reducing downtime and costs associated with overhauls, inspections, and repairs. The A/WS-100H was an improvement on the older turbojets that had would generate smoke when operating without afterburner. In service, the A/WS-100H has shown itself to be highly reliable, as evidenced by a very high operational availability, as well as having excellent durability, with a high mean time before failure rate. This has led to the aircraft retaining its certification for continuous operations for over forty years.

The A/WS-100H has been continuous improved since its introduction in the 1970's, including the addition of newer variants with higher thrust to weight ratio, more powerful afterburning capabilities and advanced fan blades. These improvements have increased power by 20% to 110 kN (22,600 lbf), and allowed higher payload capacities. The A/WS-100H-M2 was the first development of the 100 series and features an improvement of both dry and military thrust. But this comes at the cost of lower efficiency, resulting in significantly higher fuel consumption. However, it is still considered superior to earlier models. As it allowed for the possibility of obtaining further increases in thrust and endurance, the next generation of the 100 series is now under development. The A/WS-100H-M3 is a further development of the earlier -100 series, which includes a larger diameter fan blade, and a higher proportion of titanium in the core structure, resulting in lower specific static and dynamic lift losses. The A/WS-100H-M3 is the variant used in newer J.29 models such as the J.29DX and JH.29D. In addition the new powerplant offers a significant increase in maximum takeoff weight (MTOW) compared to previous versions, and allows the J.29 to carry heavier armament loadouts, thus improving its combat effectiveness against enemy fighters. The engine gives more thrust and significantly lower specific fuel consumption than the older 100 series units, allowing for longer missions.

The space between the engines generates lift, thereby reducing effective wing loading, hence improving manoeuvrability. The engines are fed through intake ramps fitted under the leading-edge extensions, which have variable ramps to allow high-Mach speeds. This allows the J.29 to operate at supersonic speeds by adjusting the ramps within the inlets to provide optimum airflow. As an adaptation to rough-field operations, the main air inlet can be closed completely with mesh screens design in the main intakes for take-off, landing and low-altitude flying, preventing ingestion of ground debris. Thereby the engines receive air through the mesh screens design in the main intakes. This was added as the Imperial Kodeshi Air Force doctrine required that aircraft could operate at alternate rough-fields during times of war as it thought that their main operating bases would quickly be destroyed. So therefore they decided to equip some of their aircraft with the ability to operate from such fields.

Performance
The J.29's combat performance, especially its speed and manoeuvrability, has made it capable of intercepting most modern fighter jets in any weather conditions and at any altitude. This high agility allows rapid deployment of weapons in any direction as desired by the crew. It's maneuverability is derived from low wing loading, powerful flight controls and high thrust-to-weight ratio making it controllable even at very low speeds and high angle of attack. In addition to highly manoeuvrability the aircraft is capable of supersonic high level flight. Due to its low drag configuration the aircraft is able to fly for extended periods of time on internal tanks at high cruising speeds.

It can reach a maximum speed of over Mach 2. At low altitudes the J.29 is extremely nimble as it is capable of performing tight turns at low airspeeds and is also capable of executing steep climbs and dives. The J.29 can climb to an altitude of about 10,000 m above sea level in around 60 seconds, depending on the load carried by the aircraft. At certain speeds, the dynamic thrust output of the two engines is greater than the total combat weight of the craft, giving the J.29 the ability to accelerate vertically. This was especially useful for the interception role as it is possible to rapidly close and engage targets intruding on its airspace. Overall the performance of the J.29 is comparable to that of a contemporary frontline multirole jet. According to its manufacturer Yu'an Aircraft Industrial Corporation (YAIC) claims that the J.29 is able to outperform many of its international rivals due to its unique combination of characteristics.

Armament
The J.29 is equipped with 7 - 13 hardpoints (depending on the model). In the J.29K, J.29D and the J.29J there are 7 hardpoints: 1 centerline, four under-fuselage (for semi-recessed carriage of Medium-Range AAMs), two under-wing (each with additional two missile launch rails),; in the J.29DX, JH.29D, and JH.29DZ there are 13 hardpoints: 1 centerline, four under-fuselage (for semi-recessed carriage of Medium-Range AAMs), two under-wing (each with additional two missile launch rails), 2 wingtip; All variants have an internal cannon. Payload for the J.29 varies from 6,804 kg (15,000 lb) in the J.29K to higher in subsequent models.

The J.29 is also equipped with an internal cannon which is the Xiabei D-30 a 30 mm gas-operated five-chamber revolver cannon using pyrotechnic cocking and electrical ignition. It fires a range of 30 mm ammunition of various types, and is capable of continuous fire or 0.5-second or 1-second bursts. It normally firing semi armor-piercing high-explosive incendiary (SAPHEI) rounds. The cannon has a rate of fire of 1,800 rounds per minute with a maximum effective range of 1,800 m. The J.29 has an ammunition magazine of 135 rounds, which was reduced to 100 rounds in later variants. The cannon's ranging is coupled with the aircraft's IRST, which has a laser rangefinder specifically for dogfighting purposes. The aircraft has a computerized system that automatically tracks and engages multiple target sources in all modes of operation, including low visibility situations.

The Initial deliveries of the J.29Ks were equipped for the air-to-air interceptor combat duties, but lacked any armament for air-to-ground operations. As it was intended to be a "pure" fighter plane the J.29K was not designed to carry ground attack weapons. Later deliveries were to the J.29D standard, which added the capability for conducting air-to-ground operations; The program was based on a requirement issued by the General Staff Headquarters to add advanced ground attack capabilities into the inventory of the Kodeshi Air Force. Currently the J.29 can use a large variety of weaponry is available including missiles, bombs, rockets, flares, chaff dispensers and electronic countermeasures pods. Some nonstandard systems include drop tank pods attached to the underside of the wings. It has provisions for laser-guided and electro-optical bombs, as well as air-to-surface missiles, anti-radiation missiles, anti-ship missiles, cluster munitions and unguided munitions.

Kodeshia
The largest operator of the J.29 is the Imperial Kodeshi Air Force. The first production J.29s entered service with the Imperial Air Force on the 7 December 1979. The initial batch of models were delivered to the 1st Test and Evaluation Squadron (TES) which was stood-up on that same year to carry out final evaluation and certification of the latest developments as the Operational Evaluation Unit for the type, allowing the J.29K to enter into mass production. By 1989, J-29s were operated by 16 squadrons of the Imperial Kodeshi Air Force. The J.29K took the role was the most potent fighter jet in service with the Imperial Kodeshi Air Force and is often fielded by the IKAF in bilateral and multilateral air exercises and competitions. It was immediately used for interception role against Tiperyn and Selengerian air incursion into Kodeshi airspace. Its first sustained combat use was as a photo reconnaissance platform. In 1982 the Air Force began an improvement programme introducing the J.29D which added new radar system that introduced ground attack and reconnaissance capabilities, increased thrust and had better performance compared with previous variants. This variant was selected to inherit the reconnaissance mission upon the departure of the dedicated recon platforms. The J.29D participated in operations against rebel forces in the northern Kodeshia. Its first sustained combat use was as a photo reconnaissance platform. It also served as the primary strike and bomber force during the late 1980s civil war, becoming the only military aircraft of the era equipped with a weapon capable of delivering precision guided munitions, a laser designator/laser target acquisition system and a highly accurate and reliable air-to-ground targeting system, thus providing a key role in the conflict in the north.

On 10 January 1983, Kodeshi J.29s began conducting reconnaissance and strike missions over northwest Kodeshia in Operation Menglong, against the rebel insurgency; J.29s were initially tasked with combat air patrols on the border with Asharistan. Later upgraded J.29D models were tasked with identifying rebel positions in support of ground and light attack airstrikes. A large tactical airborne reconnaissance pods were developed and fielded on the J.29 in 1980s to aid with operations against the insurgency in northwest Kodeshia. On 18 October 1983, J.29Ds joined in conducting attacks, launching strikes that destroyed a logistics depot and killed dozens of rebel fighters. Subsequent airstrikes in the following days by J.29s fighters were reportedly destroyed a rebel training camps, depots and facilities in northwest Kodeshia on the border with Asharistan. During the later stages of the conflict, J.29s typically conducted six-hour sorties over rebel airspace, carrying an armament of four air-to-air missiles, four or six AASM bombs, a KONSAI targeting pod and two drop tanks; these patrols required multiple aerial refuelling operations per sortie from IKAF tanker aircraft. The AASM precision-guidance weapon system, using bombs weighing between 125 kilograms (280 lb) and 1,000 kg (2,200 lb), allowed the J.29s to conduct high-altitude bombing missions.

During the 1990s, the Kodeshia Air Force continued to expand the J.29 fleet, adding new units, new types, new developments, with a number of J.29Ks receiving updates to the J.29D standard as well as a few additional upgrades. These include upgraded radars with greater resolution and higher signal strength, incorporation of computerized navigation aids, such as inertial reference system for flight control system, digital autopilot system and automatic landing system with glide slope indicator. The newest model in the series, the JH.29D, is similar to the earlier J.29D but uses the twin seat configuration of the J.29J, and incorporates all the multirole ground attack and air superiority features of the earlier variant, but features a heavily strengthen structure, larger, more efficient engine, and other improvements to the aerodynamics to improve manoeuvrability and handling, particularly with heavy weapon loads. The new JH.29D has been adopted as the primary combat fighter for the Kodeshia Air Force, replacing older generation fighters.

By 1998 developing the next evolution of the JH.29, with a dedicated tactical reconnaissance and electronic warfare role, designated by Kodeshia as the JH.29DZ. Features the removal of the cannon and IRST systems replacing them with a dedicated electronic warfare systems, allowing for better use of the aircraft in air defense operations. It is also equipped with wingtip electronic warfare pods, to allow it to perform a variety of missions in the Electronic Warfare Theatre. It is intended to perform escort jamming as well as the traditional standoff jamming mission, using both conventional and nonconventional radar jammers. The new design will feature a strengthened fuselage and wings in order to withstand weapons loads up to 5,000 pounds, which would make it capable of carrying a variety of new guided missiles.

Beginning in 2009, 176 J.29Ks would be retrofitted with the latest generation of active electronically scanned array radars to improve their range and accuracy of fire, along with additional electronic warfare suites and anti-surface missiles to upgrade the fleet to J.29DX standard. The last batch of older J.29Ks were retired in September 2017, making way for delivery of new build J.29DXs from 2018 onwards with deliveries beginning in early 2019.

The J.29 had been scheduled to remain in service with the Imperial Kodeshi Air Force until 2045, when it is envisioned a successor under development by Yu'an the J.30 as a replacement for the Imperial Kodeshi Air Force as part of the Kodeshia's wider Future Combat Aircraft Programme will enter initial operational testing in 2030, eventually entering into serial production by 2050 with deliveries commencing by 2055, followed by deployment by 2025, with a projected combat lifespan of 25-35 years.

Gardarike
The Gardarike Realm Air Defence procured its first J.29 as a multirole combat aircraft through a contract signed on 15 May 1982 valued at Hz 142.5 trillion or $10.1 billion (adjusted for inflation), between the Gardarike's Ministry of Defence and the Kodeshi firm Yu'an Aircraft Industrial Corporation for a number of J.29K aircraft. This initially consisted of J.29K and J.29Js, which were to be delivered starting in 1983 by year's end. These served as primary fighter-interceptors, only being retired in 2018 after reaching the end of their planned life span. The Realm Air Defence eventually replaced the J.29Ks with purchase of JH.29D multirole combat aircraft with the additional purchase of the JH.29DZ tactical reconnaissance and electronic warfare variant following its introduction into service on 1998. A total number of 228 J.29s remain in service with the Gardarike Realm Air Defence.

Lestykhol
After tensions between Lestykhol and Kodeshia faded in the wake of the Kesh War, a trade agreement was made that allowed the purchase of J.29E's. This was made in 1985 following the success of the J.29 against the rebels in northern Kodeshia. The deal was saw a number of J.29K and J.29J aircraft adopted as the primary fighter-interceptor for the Lestykhol National Air Force. These have since being upgraded to the J.29D, where they can carry advanced avionics such as ECM suite's and datalinks.

Prototype Models

 * Y.29FM
 * F = 原型; Yuánxíng ("Prototype"), M = 模型; Móxíng ("Model")
 * Company model number for basic prototype, nine were built.


 * Y.29FM-X
 * F = 原型; Yuánxíng ("Prototype"), M = 模型; Móxíng ("Model"), X = 现代化; Xiàndàihuà ("Modernization")

Improved prototype configuration, more similar to production models, four were built.

Production Models

 * J.29K
 * K = 空中优势; Kōngzhōng yōushì ("Air superiority")
 * Initial production variant. Single-seat all-weather air-superiority fighter version. Initial delivery of the J.29Z to the Imperial Kodeshi Air Force was in 1979. A total of 518 were built.


 * J.29J
 * J = 教練機; Jiàoliànjī ("Trainer")
 * Initial production two-seat training version variant. The design is to serve as trainer for J.29K pilot and is full combat capable. Initial delivery of the J.29J to the Imperial Kodeshi Air Force was in 1979. A total of 108 were built.


 * J.29D
 * D = 多用途; Duō yòngtú ("Multirole")
 * Improved single-seat all-weather multi-role fighter variant fitted with a more powerful radar that introduced ground attack capabilities to the aircraft giving it swing-role capability, They entered service in 1983. A total of 180 were built.


 * J.29DX
 * D = 多用途; Duō yòngtú ("Multirole"), X = 现代化 Xiàndàihuà ( "Modernization")
 * Improved single-seat all-weather multi-role fighter variant featuring new radar, upgraded engines, fully glass cockpit, mechanical flight controls replaced by a  system and more sophisticated self-defense electronic countermeasures (ECM), They entered service in 2009; still in production at least 102 have been built.


 * J.29DC
 * D = 多用途; Duō yòngtú ("Multirole"), C = 出口 Chūkǒu ( "Export")
 * Export version based on the J.29K, its export designation is FY-29E. The aircraft can be fitted with domestic systems and active ECM systems, weapons guidance aids, improved built-in check and training systems. A total of 1 demonstrator was built.


 * JH.29D
 * Z = 多用途; Duō yòngtú ("Multirole")
 * Two-seat all-weather multirole strike version and ground-attack variant, it features an upgrade over previous models with new flight control system,  radar, fully glass cockpit, additional weapons hardpoints, digital helmet-mounted systems in both cockpits; and a digital electronic warfare system among other enhancements; still in production at least 198 have been built.


 * JH.29DZ
 * D = 電子作戰 Diànzǐ zuòzhàn ( "Electronic warfare"), Z = 侦察; Zhēnchá ("Reconnaissance")
 * Two-seat all-weather tactical and  variant, it features all of the upgrades of the J.29ZG with the cannon and  removed and replaced with a dedicated  systems. It is also Equipped with wingtip   pods; still in production at least 96 have been built.

Current
 Kodeshia  Gardarike  Lestykhol
 * Imperial Kodeshi Air Force - 574 J.29 aircraft, including 176 J.29Ks, 150 J.29D and DXs, 70 J.29Js, 54 JH.29Ds, and 24 JH.29DZs
 * Realm Air Defence - 228 J.29 aircraft currently in service, including J.29J, JH.29D and JH.29DZ. J.29Ks received beginning in 1983 but retired as of 2018.
 * Lestykhol National Air Force - Received a number of J.29K and J.29J aircraft beginning in 1985.