IFSTA (Integrated Flight Test Simulator) means "Integrated Flight Test Simulator", also known as multi-axis stabilizer. It is refitted from the K8 trainer, which can simulate complex flight state, code K-8V, and has some characteristics of advanced trainer. K-8V can simulate the flight characteristics of various fighters in the air. Even before the next generation fighter is developed, the design parameters on the drawings can be input into its simulation equipment to simulate flight, so as to achieve the purpose of verification, evaluation, optimization and training. At present, the equipment can load eight groups of parameters to simulate the characteristics of eight kinds of aircraft. When researching and developing K-8V, Hongdu Group sought to cooperate with western groups such as Carlsban Company of the United States. However, on the one hand, western companies are not allowed to export advanced aviation technology to China, on the other hand, the asking price is too high. The American National Experimental School has expressed its willingness to cooperate, but only in training. Hongdu finally completed the development of K-8V mainly on his own. According to the communication between Hongdu designers and British Aerospace, it is found that although the two sides have never cooperated in the field of multi-axis stability, they have taken the same road and even used almost the same software. Compared with the BW-1 single-axis stabilizer improved by J-6, the K-8V adopts the fly-by-wire flight control system with redundancy and mechanical guarantee, and realizes three-axis stability. It is a practical variable stability test model. In the future, K-8V will develop into five-axis stability, equipped with optical fiber transmission flight control system, and realize digital full authority control of the engine.

The IFSTA flight simulation testing machine is under the responsibility of China Flight Test Research Institute, with the participation of China Aviation Accessories Research Institute, Aviation Computing Technology Research Institute and Nanchang Aircraft Company. Air flight simulator, also known as variable stability aircraft, is characterized by changing the stability of the system or aircraft through a special automatic control system, thus simulating the characteristics of other aircraft, and even simulating the flight characteristics of newly designed aircraft in the air. The testing machine was developed at the end of 199 1. The first flight of 1997 was successful, and the acceptance test flight of 1998 was completed and put into application research.

The ultimate goal of IFSTA development is to realize an airborne flight simulator with five degrees of freedom (three-axis rotation characteristics, lift characteristics and push/drag characteristics), equipped with variable human feeling characteristics, programmable multi-function display system and perfect airborne test system. It can meet the relevant technical verification and airborne simulation requirements of most military and civil aircraft except helicopters. Due to the urgent need of new model development and financial reasons, IFSTA testing machine adopts a two-step scheme in engineering realization, that is, the first step is to complete the variable stability control of three degrees of freedom (three rotating shafts), and then add the automatic control of direct lift and thrust/resistance, thus providing a perfect attitude and trajectory response simulation. The testing machine is mainly used for: flight dynamics and flight quality research; Research and verification of new technology and scheme of flight control; Flight test research, such as flight test method, parameter identification method and evaluation method of new aircraft/system; Identification of flight simulation test of new aircraft and training of first flight pilots: study the influence of man-machine interface, especially man-machine loop, on flight quality; Verification of ground simulator and correlation between ground simulation and flight test: test pilot training.

IFSTA takes the K8 jet trainer developed by Nanchang Aircraft Company as the prototype, and the front cockpit is changed to the pilot cockpit for experimental evaluation. When the telex system works, the pilot in the front cabin controls the aircraft to complete the test and evaluation task. As a safety/instructor cockpit, the rear cabin retains the complete control system and flight instrument system of the original aircraft. When the stabilizer system is not connected (i.e. disconnected), the safety pilot can use the mechanical control system of the original aircraft to control the aircraft, and the safety/instructor pilot controls the working mode (state) of the aircraft/system and the selection of test parameters. The steering gear of the variable stability system is connected in parallel with the mechanical control system of the original machine through the clutch. When the stabilizer system works, the clutch is closed, and the pilot in the front cabin controls the aircraft through the stabilizer system. When the stabilization system fails or is disconnected normally, the aircraft can be controlled by the pilot in the back cabin.

The added systems include: variable stability system: digital dual redundancy programmable fly-by-wire flight control system, which can work full-time and has full authority; The system can be pre-installed with eight groups of system/aircraft parameters or models; Equipped with standard avionics bus interface, special interface for ground test and flight test interface; The system has a good user development interface; Using BIT detection to improve security measures; When the system fails or the aircraft response exceeds the limit, you can choose to manually/automatically cut off the stable telex system. Programmable multifunctional display system: digital and computer imaging: it can simulate the tracking and attack of targets; Research and develop various display formats (head-up display and head-down display); It can complete the simulation display of virtual tasks such as air approach and landing. Automatic trim system: after the variable stability fly-by-wire control system works, the stable hinge moment of the elevator is automatically limited to 8 N m (equivalent to 2 kg lever force). Airborne test system: it can record the voice parameters of aircraft, system and pilots, and has the ability of telemetry transmission. Variable human perception system: it can meet the simulation of the control characteristics of military and civil aircraft; Provide four redundant instructions of force/displacement; Provide two-degree-of-freedom edge control instructions, and the center and edge can be replaced at any time. The aircraft/system has been modified: power supply system, hydraulic system, control system, instrument system, navigation system, aircraft structure, lighting system and landing gear.

After IFSTA was put into use, it has completed a variety of model simulations and special verification studies, such as group training of the new aircraft's chief test pilot, PIO (Pilot Induced Oscillation) research, control law verification and quality evaluation of the new aircraft's flight control system, verification test flight of a certain missile's terrain recognition system, verification test flight of the new aircraft's flutter excitation system (FES), and a large number of test pilot training and teaching test flights. In addition, after the successful development of the test machine, it has conducted extensive exchanges with foreign test pilot schools, flight test research units, air force and related research institutions on test pilot training, stabilizer design and application technology, and has been highly praised.

During the period of 1998, the fly-by-wire flight control system of the first flight team of a new fighter plane developed by our country carried out the flight characteristics training and flight quality evaluation demonstration of the K-8V stabilizer fly-by-wire flight control system. After training and demonstration, the evaluation of the test pilot shows that the approach and landing of the new fighter are more realistic, especially the human sensory system and the attitude angle response of the aircraft are realistic; Realistic in vertical and horizontal directions, with a slight sense of course damping; Pilots can obviously experience the change of flying quality when different parameters change in the air, which is a good teaching and training means. It can be used for test pilot training of this new fighter and other fly-by-wire aircraft.