H160 Dynamics Development: Setting New Standards

Flight simulator for civil aircraft can be used for pilot training. The flight test data for modelling, verification, validation, and qualification of flight simulator can be obtained through flight simulator data package flight test. In order to improve the efficiency of flight test and save the resources of flight test, the planning of flight simulator data package flight test was studied. Four principles of flight test planning were proposed, considering the requirements of flight simulator development progress, flight test planning of aircraft, aircraft configuration plan, requirements of flight simulator data package flight test and aircraft flight test. The principles included the principle of flight test method similarity, the principle of progress priority, the principle of pre-test meeting and the principle of considering configuration requirements. The principles of flight test planning given in this paper have been applied in the actual planning of flight simulator data package flight test for a certain aircraft, and the efficiency of flight test has been improved.

Many different sensor types are used in aircraft and aerospace applications in general. During the certification period of a commercial airliner, a loads survey is conducted to collect aerodynamic performance data by measuring the pressure on the surface of the wings. To do this, we developed a unique multi-MEMS pressure sensor system targeted for flight test applications. Here we describe test results collected from two aircraft flight tests using this thin profile ‘pressure belt’ multi-sensor assembly. The overall measurement accuracy was close to our targeted 0.1% of full scale, which is 10× better than the currently used technology. Lessons learned from these flight tests and approaches to further improve the pressure belt reliability are also discussed.

The present contribution describes the set-up and major results of a low speed test with an Airbus A320 wind tunnel model in high lift configuration in the ETW under cryogenic high pressure test conditions. The test is embedded in the joint LuFo IV research project HINVA (High Lift INflight Validation). The overall objective of the HINVA project is to improve the capability of CFD tools and wind tunnel testing to predict maximum lift and its determining flow phenomena in terms of accuracy and reliability. The reference for both simulation approaches is given by dedicated flight test data obtained in a flight test campaign using DLR’s ATRA test aircraft. In particular, the static aero-elastic deformations from the flight test at maximum lift conditions have been incorporated in the wind tunnel model. Moreover, attention is paid to the scaled representation of geometric features, such as slat tracks or a de-icing pipe between slat and fixed wing. The peniche height of the A320 half model is adapted to maximum lift conditions. The model is equipped with a high resolution pressure tap distribution aligned to the pressure measurement locations of the flight test aircraft. In addition to standard force, moment and pressure measurements, cryo PIV velocity field measurements have been carried out above the wing aft of the engine, as well as transitions measurements based on temperature sensitive paint. The deformation under wind loads is detected by a stereo pattern tracking system. After introducing the considerations for the model layout, the test techniques in use are introduced with selected results presented for each technique.

: The development of system identification technology was undertaken to provide for more effective aircraft flight testing by reducing the time required to conduct specific tests and/or to provide for a more comprehensive data analysis. F-14A and TA-4J flight test results presented demonstrate that the flight time required to obtain stability and control data can be significantly reduced without loss in accuracy of conventional flight test derived parameters. Presentation of S-3A and EA-6B system identification results demonstrate that this technology can be successfully used to update the aerodynamic data bases of modern jet aircraft from flight test data. These system identification results are compared with wind tunnel data and flight test derived parameters to demonstrate the accuracy of this new technology. Applications of this technology to integrate several areas of aircraft flight testing are discussed. (Author)

This paper discusses the author's experience during four flight test programs to improve the characteristics of business jet aircraft. In each case, an experimental prototype was used to evaluate aerodynamic configurations for the first time. This was invaluable because in some cases aerodynamic techniques, used to make wind tunnel models behave more like the full scale aircraft, were used for the first time to improve aircraft handling characteristics. The characteristics problems solved by simple aerodynamic modifications included wing drop (roll ofo, stable deep stall and high angle of attack divergent wing rock. The effects on high angle of attack handling of the following aerodynamic devices are discussed: strips, wing fences, vortex generators, vortilons and Delta fins. It has been my privilege, over the last several years to be involved in several characteristics development programs on business jet aircraft. These programs have been very rewarding for the following reasons; the flight test aircraft was used as a true experimental vehicle, where new ideas were tested for the first time, the test pilot was an integral part of the engineering development team, the programs led to significant improvements in aircraft handling and, therefore, safety and in each case, the end result was a simple, inexpensive aerodynamic change to the aircraft. It is not unusual for there to be differences between the characteristics predicted by wind tunnel tests and those seen during flight tests. When this occurs, some developmental flight testing is required. General aviation seems to be the only flight test area where a true experimental flight test program is economically feasible and I believe that this was critical to the success of these programs. In several cases, the devices used to modify aircraft characteristics were the same as are used to reduce scale effects to make windtunnel models behave more like the aircraft. The characteristics problems solved by simple aerodynamic modifications included wing drop (roll off), stable deep stall and high angle of attack (AOA) divergent wing rock. Several hundred aerodynamic configurations and many thousands of stalls were flown during these very intense flight test programs. As many as four configurations were flown per day. Even though these were hazardous tests, no incidents or aircraft damage occurred during the tests. The effects on high AOA handling of the following aerodynamic devices was evaluated; strips, wing fences, vortex gencrators, vortilons and Delta fins.

Low-cost digital data acquisition systems have substantially transformed how aircraft flight testing is taught at The Ohio State University. With the advent of smartphones with built-in sensor suites, students now have access to modern data acquisition techniques and an expanded envelope of aircraft characteristics that can be measured in flight, and with much greater fidelity. A recent AIAA conference paper (Gregory and Jensen, AIAA-2012883) details the initial implementation of digital data acquisition techniques for flight testing education, with a specific focus on smartphone-based systems. However, that work showed that altitude measurement with smartphone-based GPS was highly erroneous. This work seeks to assess the accuracy of barometric pressure sensors on smartphones for measurement of altitude in flight, and how well cabin pressure may be used as a proxy for freestream static pressure. Results presented here indicate a measurement accuracy of ±40 ft, which improves to ±15 if the difference between freestream static and cabin pressures is calibrated and accounted for.

Methods of the actual values of the angles of attack and slip determination in the technology of air data systems estimation using satellite navigation systems during aircraft flight tests of are stated. Also methods of parametric identification of mathematical models of on-board aerodynamic angles measurements errors are presented. The technology has been developed and implemented in the practice of flight tests at Flight Research Institute. The technology shows high efficiency of solving tasks of air data on-board systems, vertical separation systems, flight performance and takeoff and landing characteristics estimation in flight tests. The technology covers a wide range of issues of aerometric measurements, many of which have already been published. Here, attention is paid to measurements of aerodynamic angles. The features of determining the angles of attack and slip using data from air data systems, satellite and inertial navigation systems are shown. Equations for determining the angles of attack and slip during testing, factors of measurement errors, the structure of the mathematical model of the aerodynamic errors of the angle of attack on-board measurements are presented in a stationary approximation. Algorithms for solving problems in steady and unsteady modes of flight, takeoff and landing are considered. The completeness of the solution for the wind speed vector is noted. Estimates of methodological errors in determining aerodynamic angles using the technology are made. Compliance with modern requirements is showing. The effectiveness of the technology is confirmed by the materials of flight tests of a short-range aircraft. Typical examples of test materials presentation, features of measurements depending on the type of test mode, aerodynamic influence factors are shown.

Nonclassical flutter has been observed during transonic conditions associated with flight and wind tunnel testing of various fighter and bomber aircraft As contrasted with classical flutter the underlying mechanism has been ascribed to a phase lag between lift variations and wing motions Based on the observations that the wing oscillations were restricted to bending mode shapes similar to the free fundamental, the phenomenon was idealized as the lift induced forced oscillation of a Cantilever beam simulating the wing. Coupling with the aerodynamics occurs through the beam equation forcing term, representing the lift, and the tangency boundary condition for the unsteady transonic small disturbance equation for the latter Strip theory has been used with a suitably revised version of LTRAN2 to supply the aerodynamic input The resulting time integration algorithm provides a procedure to determine the destabilizing effects of sweepback Computations with the method closely predict flutter frequencies observed for the HiMAT canard during wind tunnel testing, as well as for the B-l wing in flight tests in two out of three cases Qualitative behavior of the oscillation agrees for these conditions For the third case, damped oscillations are predicted rather than the amplified ones observed Reasons for the discrepancy are provided, involving the second bending mode of these oscillations in contrast to the fun damental assumed by the current approach Specific recommendations for refinements of the procedure in volving inclusion of modal coupling analysis of limit cycle aspects and three dimensional phenomena are given

In aircraft flight test phase, in order to verify whether the aircraft has reached the reliability requirements, we need to assess its reliability. Firstly, in this paper we review the reliability estimation method under multi-profiles that can be used to evaluate the reliability of aircraft during the flight test process and analyze its shortcoming. Then, in order to expand the amount of data, we describe how to incorporate the environment conversion factors into the reliability estimation method under multi-profiles. By the way, taking into account the varied population-environment feature of data, an integrated evaluation model of flight test of reliability was established. This model is making up the weak points of previous models, and improving the accuracy of reliability evaluation. Finally, this method applied in a real engineering example is described.

The United States Air Force Test Pilot School (TPS) performs six to eight flight test management projects (TMP) annually. The TMPs cover all aspects of flight test including performance, flying qualities, avionic systems, and human factors. The flight tests are performed for a wide variety of government agencies and commercial sector companies. Test teams are composed of TPS students with a broad base of aviation and research flight experience. Student teams consist of four to six students made up of a 50/50 percent pilot/engineer mix. The test projects address all phases of testing from program introduction, through test plan working groups, technical/safety review boards, and test execution, to final oral and written reports. The test execution occurs over a period of 3 to 4 weeks and generally encompasses 4 to 20 flight test sorties. This paper provides the background of the USAF Test Pilot School program in general and the test management projects in particular. An overview of TPS technical capabilities and resources is provided. Examples of recent TMPs are detailed. These examples include efforts with Air Force research laboratories, Air Force major commands, and Technology Transfer programs using Cooperative Research and Development Agreements between the government and private companies INTRODUCTION The United States Air Force Test Pilot School (TPS) is the premier institute for training test pilots, test navigators, and flight test engineers in the conduct of flight test and evaluation of research, prototype, and production aerospace vehicles, systems, and weapons. The capstone event of the TPS curriculum is the test management program (TMP) in which student teams perform an extensive flight test project in support of a broad base of outside agencies. The TMP provides comprehensive end-to-end training in all phases of test management and execution. These programs provide students with practical hands-on test experience from program introduction to writing the final report and providing oral presentations of test results, conclusions, and recommendations to the customer and Air Force Flight Test Center (AFFTQ leadership and technical personnel. The program presents students the opportunity to apply the technical, management, and leadership concepts taught during the course. Emphasis is placed on understanding customer technical requirements within the constraints of cost and schedule demands. To date, TPS has been exceptionally successful in meeting customer requirements and providing real world training for its students. The purpose of this paper is to highlight our recent programs, and to inform outside agencies of our capabilities to perform low cost, quick-reaction flight test programs. USAF TEST PILOT SCHOOL COURSE OVERVIEW The USAF Test Pilot School provides training in three courses: the Experimental Test Pilot Course, Test Navigator Course, and Flight Test Engineer Course. The courses are integrated to instill cooperation and understanding between test team members which is essential for successful flight test operations. Data group teams plan, fly, evaluate, and report on selected test projects throughout the course. The flying program for the pilots develops the knowledge, flying precision, and powers of observation necessary for successful flight evaluations. The flying program for navigators and engineers leads to an understanding of problems pilots encounter and familiarizes them with airborne test tasks needed to accomplish precise flight test techniques. Navigators and engineers perform extensive evaluations of airborne avionics and weapons systems to determine suitability under operational conditions. The course is divided into four phases: (1) Performance, (2) Flying Qualities, (3) Systems Test, and (4) Test Management The Performance Phase develops the theory and methods of evaluating aircraft takeoff, climb, cruise, descent, turn, acceleration, propulsion, and landing performance. The Flying Qualities Phase examines the stability and control characteristics which influence the ease of safely flying the aircraft during steady and maneuvering flight in execution of the total mission. During this phase, aircraft are tested to determine static and dynamic characteristics, estimate stability parameters, evaluate flight control system effectiveness, and measure engine-out handling quality characteristics. The Systems Test Phase evaluates aircraft avionics and their system integration. The Performance, Flying Qualities, and System Test Phases all have integrated academic and flying programs to maximize student training effectiveness. The Test Management Phase academics are integrated throughout the program with the actual test management project execution occurring during the latter part of the course. USAF TEST PILOT SCHOOL TECHNICAL RESOURCES The curriculum is supported with state-of-the-art instrumented aircraft and contemporary data acquisition and analysis systems. TPS serves as a self-contained Combined Test Force (CTF) providing extensive technical capabilities for complete flight test engineering. TPS instructs basic flight test techniques with four instrumented T-38A aircraft. The T-38A aircraft are instrumented with sensitive cockpit instrumentation (airspeed, altimeter, mach, g, angle of attack, and sideslip gauges) and a programmable data acquisition system. All four aircraft possess onboard data recorders and telemetry

For many years, the Airbus Test Center has explored new ways of measuring with the optical fiber, mainly Fiber Bragg Grating sensors for temperature, stress, bending...This low intrusive instrumentation procures the advantage to be almost transparent, making aerodynamic effects negligible.Moreover, the insensitivity to the electrical environment due to its high level of galvanic insulation, enables measurement in a high Voltage environment which was nearly impossible with classical sensors.This presentation will describe the main difficulties, benefits and results obtained in the frame of several Flight Tests campaigns.

A combination of experimental and analytical methods has been applied to study the aerodynamic interaction of the S97 RAIDER® coaxial main rotor and its wake on an empennage. The primary goal was to characterize the periodic aerodynamic forcing from the rotor on the horizontal stabilizer over a wide range of flight conditions, and use those data to develop and validate computational fluid dynamics (CFD) methods that can then be applied to optimize future designs. The flight test aircraft was instrumented with 29 unsteady pressure sensors and flown for speed sweeps from 20 to 180 kts as well as a range of maneuvers. The data were processed to provide both unsteady and time-averaged aerodynamic forces and moments. Two CFD codes were then applied: HELIOS/RCAS using discrete main rotor and propulsor blades and STARCCM+ using a recently developed unsteady virtual blade model. Both codes captured the trends of the flight test data and agreed that the vibratory aerodynamic forcing on the empennage was not particularly large. The flight data were also compared with previously acquired powered wind tunnel model data, and showed good agreement. Finally, the Sikorsky GenHel flight dynamics model was applied to level flight and maneuver conditions, and the match was also acceptable. This study has that current state-of-the-art methodology, carefully applied, can capture complex aerodynamic interactions with sufficient accuracy for aircraft design, and that this implementation of X2 Technology(TM) does not result in unacceptable rotor on empennage interactions.

Lidar (light detection and ranging) is a well-established measurement method for the prediction of atmospheric motions through velocity measurements. Recent advances in 1.5 μm Lidars show that the technology is mature, offers great ease of use, and is reliable and compact. A 1.5 μm airborne Lidar appears to be a good candidate for airborne in-flight measurement systems. It allows measurements remotely, outside aircraft aerodynamic disturbance, and absolute air speed (no need for calibration) with great precision in all aircraft flight domains.In the framework of the EU AIM2 project, the ONERA task has consisted of developing and testing a 1.5 μm anemometer sensor for in-flight airspeed measurements. The objective of this work is to demonstrate that the 1.5 μm Lidar sensor can increase the quality of the data acquisition procedure for aircraft flight test certification.This article presents the 1.5 μm anemometer sensor dedicated to in-flight airspeed measurements and describes the flight tests performed successfully on-board the Piaggio P180 aircraft. Lidar air data have been graphically compared to the air data provided by the aircraft flight test instrumentation (FTI) in the reference frame of the Lidar sensor head. Very good agreement of true air speed (TAS) by a fraction of ms−1, angle of sideslip (AOS), and angle of attack (AOA) by a fraction of degree were observed.

The measurement of takeoff and landing distance during flight testing of general aviation aircraft requires an accurate measurement of aircraft position over the ground and altitude up to 50 feet above surface elevation. Current methods of evaluating takeoff and landing distances include cinetheodolites, laser and radar trackers, and Differential Global Positioning Systems. The use of laser altimetry to get altitude above the ground originated with military and agricultural aircraft. The AgLaser module was an infrared laser ranging unit designed for agricultural aircraft to gauge optimal spray height above a field. The AgLaser system has a stated accuracy of 2.0 inches and a maximum range of 500 feet. By integrating the AgLaser system into the Flight Test Data Acquisition System designed at Florida Institute of Technology, the ability exists to measure takeoff and landing distance more accurately than currently acceptable methods. The integration of the laser module and the instrumentation unit occurred across an RS-232 serial connection and a modified LabVIEW interface. Through a series of ground and flight tests conducted at Florida Institute of Technology and Valkaria Airport, the integrated system was validated. Data from this research can be presented to the Federal Aviation Administration for consideration as an accurate, cost-effective means of measuring takeoff and landing distances for aircraft certification per 14 CFR Part 23.

Knowledge of propeller or rotor blade behaviour under real operating conditions is crucial for optimizing the performance of a propeller or rotor system. A team of researchers, technicians and engineers from Avia Propeller, DLR, EVEKTOR and HARDsoft developed a rotating stereo camera system dedicated to in-flight blade deformation measurements. The whole system, co-rotating with the propeller at its full speed and hence exposed to high centrifugal forces and strong vibration, had been successfully tested on an EVEKTOR VUT 100 COBRA aeroplane in Kunovice (CZ) within the project AIM2—advanced in-flight measurement techniques funded by the European Commission (contract no. 266107). This paper will describe the work, starting from drawing the first sketch of the system up to performing the successful flight test. Apart from a description of the measurement hardware and the applied IPCT method, the paper will give some impressions of the flight test activities and discuss the results obtained from the measurements.