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Air Systems Research Center

Outline

The Air Systems Research Center conducts research, test and evaluation on aircraft, related components and missiles.

Aircraft Research Division

Research on system integration of aircraft and component technology for aircraft, aircraft-related equipment and missiles.

Engine Research Division

Research on system integration of engine and component technology for aircraft and missiles.

Missile Research Division

Research on system integration of missiles and component technology for missiles.

Tsuchiura Branch

Environmental test and combustion test of rocket motors.

Niijima Branch

Service for firing test of missiles.

Researches for Future Fighter

Concept of Future Fighter

“Future Fighter R&D Vision” (in Japanese)

Network Shooting

“Network shooting” will be a game changer for the future fighter. “Integrated Fire Control for Fighters (IFCF)” system will realize the network shooting.
 Network shooting is a concept of cooperative missile shooting which is realized by communication network between fighters. In the process of missile shooting, search and track of targets, launch of missile, and guidance of missile are shared among multiple platforms. With this capability, air-to-air combat beyond visual range is expected to become highly effective since each fighter can be free from positional and directional constraints by sharing and transferring fire control to wingmen. IFCF system consists of high-speed intra-formation data link subsystem, fire control computer and software.

The prototype of IFCF software has been tested and modified through the pilot-in-the-loop simulations, which demonstrate the effectiveness of network shooting under various situations, such as air defense operations in a quantitatively disadvantageous manner.
 Prototyping of intra-formation datalink subsystem is now undergoing, and will be verified in the flight test.

Cockpit View of the IFCF Simulator
Prototype of the Data Link Subsystem

Superior Stealth

Weapons bay
Stealth (serpentine) intake duct

Stealth is a key technology for the future fighter to acquire low-probability-intercept capability.
 The internal weapon bay system and the stealth intake duct are effective measures to reduce radar reflection from externally carried weapons and engine inlet, respectively.
 Other technologies, the lightweight airframe structure and the electric actuation system are also required to realize the stealth fighter.

Weapons Bay System for Stealth Fighters

The safety of weapon release sequence should be secured under any flight conditions including high-speed and accelerated maneuvers.
 The complicated aerodynamic flow field around the weapons bay and missiles was investigated by wind-tunnel tests and CFD (Computational Fluid Dynamics) in the early phase of the research. The internal weapons bay system with an air to air missile launcher was prototyped and its performance was verified in the ground test; safe and quick sequence of door opening, weapon separation, and door closure was successfully demonstrated under various simulated flight conditions.

Weapon release sequence of the full-scale internal weapons bay system

Stealth (Serpentine) Intake Duct

Stealth Intake Duct is a serpentine intake duct to make an engine inlet invisible from the front side, which suppresses Radar reflection, however, it causes the distortion of the air flow due to vortices and flow separation, resulted in unstable engine operation.

The air flow control is the methodology to improve the aerodynamic characteristics of the stealth capability. Aerodynamic data acquired through wind-tunnel tests improved the design of the stealth intake duct and the accuracy assurance of the CFD estimation.
 The wind-tunnel model of the stealth intake duct including the boundary layer control system for the air flow control was tested at the tri-sonic wind-tunnel of Chitose Test Center of ATLA and demonstrated the low-level of air flow distortion.

Overview of Wind Tunnel Model
Wind Tunnel Model in Tri-sonic Wind Tunnel

Lightweight Airframe Structure

The internal weapons bay system and the stealth intake ducts, applied to the stealth fighter, increase structural weight because of large fuselage volume. The integrated bonded structure and heat-shield technology are introduced to reduce structural weight.
 The integrated bonded structure is a unified fastener-less structure which can be realized by prominent composite materials and bonding technologies. Heat-shield materials can shield heat from engines to airframe structure, which can increase usage of lightweight materials. Efficient and accurate structural analysis techniques are required to apply those technologies.

In the research on lightweight airframe structure, those technologies are being verified in several phases. In the first phase, the test article of the fuel tank sections was fabricated and subsequently tested by loading the simulated fuel pressure. Test results were used to validate the bonding technology and the analytical strength estimation. The full-scale mid-fuselage was tested under various simulated in-flight loading conditions. Strength tests under severe environment are now being carried out.

Electric Actuation System

The aircraft surface design of stealthy fighter is more demanding than that of conventional one. In the design, a lot of attention is paid for the size and the position of access panels. Such design parameters depend in large part on maintainability regarding hydrostatic equipment inside body. A promising solution is that replacing conventional hydrostatic actuator with electric one. This technology will lead tremendous advantages for stealth, maintainability and even survivability.
 ASRC has been conducted the study of electric actuation system. In the study, Electro-Hydrostatic Actuator (EHA) and Electro-Mechanical Actuator (EMA) attaining reduced size and weight with careful consideration of environmental stress and electromagnetic compatibility which covers fighter aircraft flight performance have been investigated. The design and prototyping of the electric actuation system have been conducted. Ground test will be carried out.

High-Power Slim Engine Technology

To realize the stealth, high-altitude, and high-speed combat capability of a future fighter, ASRC is actively carrying out research on a fighter engine that achieves both "slimness" and "high-power thrust" simultaneously. Following the research of low-pressure components and of core engine system employing examined core engine components, "XF9-1", a prototype of high-power and slim fighter engine was successfully manufactured. ASRC is now evaluating the performance of "XF9-1" through engine run testing. ASRC drives achieving cutting-edge technologies for an engine that can be installed in the future fighter.

Ground testing on the XF9-1

The XF9-1 has completed manufacturing in June 2018 and started testing from July 2018 to demonstrate design performance. In early August, ASRC successfully demonstrated the targeted maximum thrust of the 15 ton force.

XF9-1 installed in IHI engine test cell

Technical Evaluation of Core Engine

The core engine, which is the very “heart” of the state-of-the-art engine, has been tested at ATF of Chitose Test Center of ATLA before the test of XF9-1, including the performance demonstration at flight condition and the demonstration of the maximum combustor outlet temperature “1800℃”. Acquired data were actively reflected in the design and manufacturing of the XF9-1.

Core engine at Chitose Test Center ATF

ATF: Altitude Test Facility

Technical Evaluation of XF9-1

The XF9-1 has been tested from September 2019 to October 2019, including the performance demonstration at flight condition. The technical demonstration by engine tests has been conducted until July 2020.

XF9-1 engine at Chitose Test Center ATF

Technologies Underpinning the XF9-1

Realization of High-Power Slim Engine

  • High-pressure ratio fan achieving high specific mass flow rate and high efficiency.
  • Core engine demonstrating successful operation at high combustor outlet temperature of 1,800℃.
  • Highly-loaded counter-rotating low-pressure turbine driving high-pressure ratio fan.

Realization of World Leading High Combustor Outlet Temperature

Low Cycle Fatigue (LCF) rig test for high-pressure turbine blade

  • Weight reduction of the compressor by shortening the axial length.
  • Increased combustor outlet temperature, applied with an efficient cooling structure.
  • Application of cutting-edge material to the high-pressure turbine, enabling world-leading high combustor outlet temperature.

Improving adaptability of jet engine for future fighter

With inherit results of prototyped engine (XF9-1), project is being carried out to improve adaptability of new jet engine component technologies in order to deal flexibly with requirement of future fighter.

Thrust Vectoring Control Technology

To realize high maneuverability and high stealth capability of a future fighter aircraft, ASRC is engaged in research on Thrust Vectoring Nozzle (TVN) technology. The TVN technology makes it possible to control the attitude of the aircraft by deflecting the exhaust jet, i.e. vectoring the engine thrust, which effectively supports the function of the conventional aerodynamic control surface.

Sketch of the concept showing a comparison of conventional aircraft and aircraft with TVN Technology

In this research, ASRC prototyped a TVN (XVN3-1) which can change the direction of an engine exhaust jet by up to 20 degrees from engine axial direction in all around. ASRC plans to mount XVN3-1 on XF9-1 and evaluate its performance by ground engine tests.

Researches Related to UAV

ATLA is planning to research aerial autonomous technologies through the real environment test and evaluation of an OPV (Optionally Piloted Vehicle), game changer technologies such as manned-unmanned teaming and AI (Artificial Intelligence) technologies.
 ASRC has conducted research on airborne sensor system for ballistic missile warning, which includes a flight demonstration of an OPV. For a highly autonomous aircraft and manned-unmanned teaming, ASRC has been studying on dynamic path planning and flight control system leveraging a UAV’s maneuver capability, and user control interfaces. Also, fundamental research on AI for combat support is in progress. Taking full advantage of outcome of these research projects, ASRC will further promote research projects for future intelligent UAV systems.

Airborne Sensor System for Ballistic Missile Warning

A warning mission using aircrafts for BMD is operated in a monotonous and danger situation for a long time, which is quite severe for human crews to carry out. It is expected that UAVs with an IR sensor for the detection of the ballistic missile conduct such tough missions.
 Not only an early detection technology with high performance IR sensor, it is required to establish continuous surveillance technology, which allows autonomous flight-trajectory generation under various weather condition and unmanned operation such as collision avoidance and autonomous take off/landing.
 OPV is one of the effective methodology for evaluation of these technologies, an aircraft modified from manned one, which allows to choose between manned and unmanned flight, as necessary.

Flight Test Setup

In this research, autonomous flight-path generation technology considering weather condition are demonstrated in step-by-step through Physical-Simulation Test. A KM-2D type aircraft is customized as an OPV demonstrator with an IR sensor and equipment for demonstrating autonomous flight. The first flight was in October, 2018.
 From October 2019 to November 2019, ASRC conducted the flight tests of this demonstrator aircraft for the verification of the continuous surveillance technology, in Taiki Multi-Purpose Aerospace Park and surrounding airspace in Hokkaido.

Guided Weapons Related Research

Missile Guidance Technology in High Altitude and Speed Target

In order to intercept high altitude and high speed threats such as ballistic and hypersonic cruise missiles, it needs high maneuverability and high guidance accuracy to guide an aerial interceptor missile to threats at high altitude. However, the interceptor cannot have high maneuverability only using aerodynamics because there are not enough air density at high altitude. This fact increases the need for technology to improve the maneuverability of interceptor without depending on aerodynamics.
 This research realizes missile guidance technology which combines Side Thruster and Thrust Vector Control (TVC) to achieve high maneuverability at high altitude domain for intercepting high altitude and high speed threats. Side Thruster generates force toward pitch direction. TVC changes a direction of thrust vector by the small tabs. Combination of these technologies are expected to realize the interceptor for high altitude and high speed threats.

Schematic of Interceptor missile for high altitude and high speed threats

Predictive Optimal Guidance Technology

Recent fighters (or bombers) tend to obtain the stealth capability in order not to be detected by the radar of enemy missile or fighter. In case of detecting or tracking the stealth fighter (target) the range for guidance between missile and target is getting shorter and shorter. It should turn harder and harder for missile to kill the maneuvering target for missile evasion. This new technology enables the missile to attain effective guidance by repetition of both the application of model predictive control and the closing simulation with the estimated target maneuver based on the observed target information, which could finally produce the efficient missile guidance path against the maneuvering stealth fighter.

HILS(Hardware In the Loop Simulation) test at ASRC
Field Test at Niijima test field
 

Image-guidance Technology for Low Contrast Target

Conventional optical seekers with detection algorithm capturing the temperature difference between target and background, have a difficulty in detecting targets from low contrast scene in temperature (e.g. anchored warship near wharf or tactical vehicle parked on the road). In this research, ASRC committed to construct a novel image processing algorithm for the future optical seeker, which enables to detect and identify “low contrast target” from the background with temperature nearly equal to the target. Furthermore, ASRC researches the evaluation method for the algorithm. ASRC is working on the research to achieve these algorithm applying feature amount detection technique and image matching technique with database.

Future Fire Control Radar Technology

Recently, the aerial attack on a ground object tends to be conducted by multiple threats simultaneously. In order to improve the capability of fire control radar against aerial multiple threats, such as stealth fighters / bombers, high-speed air-to-surface missiles, low-altitude cruise missiles, etc., a research on radar resource control according to the characteristics of threats is conducted.

Millimeter Wave Fire Control Radar Technology

In order to defeat approaching landing boats, combat vehicles and others in near field, Fire Control System (FCS) using optical sensor could be ordinarily applied. On the other hand, in smoke screen or foggy condition, such FCS is apt to be restricted operationally. Compared with optical sensors, a millimeter wave radar has much more capability to detect targets even in smoke screen or foggy condition. Therefore, a research on millimeter wave fire control radar is conducted to dealing with seaborne, ground and aerial threats.

Jet-fueled Dual-mode Scramjet Engine

Scramjet engine is a game-changing technology to provide a missile with outstanding stand-off defense capability since it realizes the hypersonic(Mach 5 or higher) cruise at such a high altitude where aerodynamic performance by control surface of conventional interceptors declines.
 Compared with hydrogen, jet-fuel which is a kind of hydrocarbon fuel offers such advantages as high volumetric energy density, low cost, and relative simplicity of operation for tactical applications. Employing ramjet/scramjet dual-mode operation, wide range of flight altitude and speed can be covered by single engine and then that enables us to design a simple-structured and compact hypersonic flight vehicle.

Sectional view of a hypersonic vehicle

ASRC and Japan Aerospace Exploration Agency (JAXA) are jointly investigating combustion performance of a jet-fueled dual-mode scramjet engine and cooling ability of a jet fuel for a regenerative cooling system of the engine. In FY2017/18, a model combustor that simulated the main portion of the engine and a flow path equipped to the engine walls were designed and tested. The model combustor was well-characterized through firing tests using a blow-down-type wind-tunnel facility with direct-connect configuration.
 Furthermore, heat transfer coefficient of the fuel was acquired using a cooling channel. Subsequently, ASRC started a research program on a flight-like dual-mode scramjet engine system in FY2019, and has been working on demonstration of the engine system in ground facilities.

Design concept of model combustor
Combustion behavior (chemiluminescence observed in model combustor)

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