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PAF s' Specials
JF-17 Thunder: A Giant Leap

By Wing Commander Abid Ali Khan/Sqn Ldr Ahsan Rafiqui

Pakistan's success in joint design and development of a fighter trainer, Karakoram-8 (K-8), was a stagger­ing achievement. This encouraged our policy makers to undertake a giant step that is, the design and development of a state-of-the-art aircraft. It was realized that an advanced fighter would be required by Pakistan Air Force in near future to narrow the rising gap of its advanced aircraft inventory as com­pared to India. It was also necessary to give the much needed boost to the nation's developing aviation indus­try. The Air Staff proposal of co‑designing, co-developing and co-manufacturing with the Chinese government the JF -17 Thunder was finalized in 1999. The aircraft was to be developed as planned replace­ment of aging fleets of A-5, F-7 and Mirage of Pakistan Air Force. In the development phase, five prototypes (PT) were planned to be manufac­tured for verification of the aircraft's performance through ground tests, flight tests and demonstrations.

JF-17 is jointly designed at Chengdu Aircraft Design & Research Institute (CADI) and the prototypes are being developed and manufactured by Chengdu Aircraft Industry Corporation (CAC). In order to ensure effective transfer of technology and expertise, Pakistani experts remained associated with all aspects of design, development and manu­facturing in China. Most of the JF-17 aircraft planned to be inducted in PAF will roll out from Pakistan Aeronautical Complex (PAC), Kamra. President of Pakistan laid the foundation stone for establishing the required infrastructure for this unique manufacturing facility at Kamra on May 5, 2005.The joint development of a new generation multi-role fighter aircraft called Super-7/FC-1 (Renamed later as Joint Fighter-17 (JF-17) and code­named as "Thunder") formally started in 1999 to meet the objectives. Based on their mythology of dragons and fairies, the Chinese also call this fighting machine as "Xiao Long" (A small dragon). The first prototype flew its maiden flight in August, 2003, and the second fly worthy pro­totype took off from Chengdu in April, 2004. The joint flight test team has flown a number of verifica­tion sorties on the available prototypes and suggested various changes to enhance the aircraft's flight quali­ties, performance, structural integri­ty and the functionality of different systems. These recommendations have given a new look to the third flyable prototype. This new proto­type is planned to enter the skies in the first half of 2006.

JF-17's designers say that the strength of the Thunder lies in its advanced aerodynamics and state-of-the-art avionics. It is one of the only two current modern time fight­ers incorporated the latest research on intake design. In order to improve the aircraft's performance, study on diverterless supersonic intake has been in progress since 1999. Bump intake design on JF- 17 took almost two years with a number of intake models subjected to high and low speed wind tunnel tests. Analysis show that at high speeds, the bump works with forward-swept inlet cowls to give high performance, high total pressure recovery, low integrated distortion, and, good engine/intake matching. It redirects unwanted boundary layer airflow away from the inlets, essentially doing the job of heavier, more com­plex, and more costly approaches being used for because intake is one of the three major forward scatters of an aircraft (30%-35% contribution to aircraft forward Radar Cross Section (RCS)). In order to fully exploit the potential of the aircraft fly-by-wire system and improve the aircraft per­formance, JF-17 design has a wing fore body strike which is about 9% of the Wing area. This has resulted in better matching of the aerodynamic focus with the Center of Gravity (CG) and better harmonization of the air-to-air and air-to-ground CG vari­ations by taking advantage of the pitch digital fly-by-wire Flight Control Systems (FCS). This has improved not only the controllability but has also enhanced the performance through reduction of the supersonic drag. The salient features of "Thunder or Xia Long" enable it to outfit many competitors in the world. As a light weight, all weather, multi-role aircraft with maximum speed of Mach 1.6 (700 knots), high thrust­-to-weight ratio and hybrid flight con­trols, JF-17 gains comparative agili­ty and maneuverability in all regimes vis-a-vis fighters of the same class. Moreover, a state-of-the-art avionics package comprising modern concept of Man Machine Interface (MMI) with full Hands On Throttle-And-Stick (HOTAS) and glass cockpit make it comparable with even fourth generation fighters. This specific feature enhances its ability in all operational scenarios.

This multi-role, third generation air­craft is designed to be highly maneuverable with fly-by wire flight controls in pitch axis and stability augmentation system in the "Role and Yaw" axis. It will have the capa­bility to perform air defence, inter­diction, airfield strike, precision strike, and escort missions. It will allow long Combat Air Patrol (CAP) time at low level, thus affording large radius of action and thereby exceeding the PAF Air Staff require­ments in surface attack mode.

The aircraft is powered by reliable RD-93 engine, which like any other modern aircraft engine, is equipped with a Digital Electronic Engine Control (DEEC). Besides enhancing the engine performance, this makes engine handling carefree under all conditions and at all altitudes. Low Specific Fuel Consumption (LSFC) turbofan engine and low drag aero­dynamic design ensure its longer endurance and range. Because of its single point pressure refueling sys­tem, the aircraft has overall reduced turn around time. Modular mainte­nance design of the aircraft makes accessibility of the components quick and easy. All maintenance panels and components are installed at man's height for ease of mainte­nance. Computer-controlled fault diagnosis and analysis system not only reduce maintenance cost but also introduces the concept of "maintenance on fault only".

Long range radar and Active aircraft Beyond Visual Range (Active BVR) missile through effective integration with on board avionics provide pilot with a first shot capability. An elec­tro-optical self-protection suite with Missile Approach Warning system (MAWS) enhances its survivability under combat situations. Tactical datalink, with Track-While-Scan (TWS) and Dual Target Track (DTT) modes of the radar provide the pilot, an excellent Situation Awareness (SA) in all conditions. An integrated IFF interrogator along with colored displays provides easy cues for criti­cal decision-making.

JF-17's air combat capability is aug­mented by helmet-mounted display and all-aspect missiles affording high off-boresight launches. With its embedded data link and secure radios, the aircraft is expected to remain viable in future hostile bat­tles, and would prove to be an effec­tive low-cost high performance air defence fighter. It provides an affordable and efficient air-to-air mission capability. On the other hand, due to its advanced aerody­namic design, weapons carriage capability and avionics suite, it can strike the enemy, where it hurts him most in an offensive counter-air campaign. JF-17 thus would not only be lethal but will also be highly survivable.

Long range radar with multi-track and multi-target capabilities make Thunder a good choice for strike escort role. It can target the CAP air­craft while pushing the enemy away from the strike package. Its fire and forget capability reduces time on tar­get and thus ensures better surviv­ability. With the integration of AEW&C, JF-17 will have excellent SA even in enemy area to make crit­ical engagement and exit decisions. Furthermore, under hostile conditions, automated self-protection sys­tem of the aircraft affords high sur­vivability rate.

Large Radius Of Action (ROA) of Thunder and its weapon system capability make it an excellent light surface attack aircraft. Ring Laser Gyro (RLG) based Inertial Navigation System (INS) with embedded Global Positioning System (GPS) provides the capability of precision navigation over the entire ROA. It can carry multitude of external stores including conven­tional general purpose bombs, clus­ter bomb units, anti-runway bombs, anti-ship missiles and precision guided weapons that exist today. JF-­17 provides employment flexibility to suit the tactical conditions. JF-17's payload options make it airfield, pre­cision or maritime strike capable. It can be employed even for interdic­tion, armed reconnaissance, battle­field interdiction and close support roles.

It is designed to ensure effective MMI in all types of missions. Its efficient HOTAS controls and col­ored Smart Multi-Function Displays (SMFDs) provide ease of comprehension and control. The aircraft has a wide 24 degree Field Of View (FOV), Smart Head-Up-Display (SHOD) and Helmet-Mounted Display (HMD) provide the requisite menu based controls and displays to the pilot. The symbologies are designed to ensure high SA of the pilot both in air-to-air and surface attack missions. Its Identification Friend or Foe (IFF) interrogator for both air-to-air and air-to-surface applications is available to avoid fratricide in hostile conditions. This advanced MMI concept affords com­puter-controlled capability diagnosis and failure monitoring system to reduce the pilot's work-load. Therefore, the performance index of JF-17 is much higher than that of a second or third generation aircraft, both in air-to-air and air-to-surface scenarios. It would therefore not only meet the objectives for which it is being developed but would also truly prove to be a "Giant Leap" for our progressing aviation industry, thus paving the way for future growth in related fields.

Published in 2005/2006 60th Anniversary Special Hilal Magazine Issue.

 
 
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