H. R. Jex, R. E. Magdaleno, and D. Lee, Virtual Reality Simulation of the '03 Wright Flyer Using Full Scale Test Data, presented at AIAA Modeling and Simulation Technology Conference, Denver, CO, 14-17 August 2000. (AIAA 2000-4088, STI-P-571)The Los Angeles Section of AIAA is building a close replica of the Wright 1903 Flyer for the First-Flight Centennial in 2003. Part of the project includes the development of a modern virtual-reality flight simulator to be used for: safe training of the 2003 test pilots; updating the 1903 Flyer aerodynamic and structural models; and developing a three-axis stability augmentation system to cope with the unstable aerodynamics in the pitch and roll axes. Other purposes are to document the value of Wright Brother's design features (such as the wing-warp to rudder crossfeed) and validate the modifications of 1904-1905 as they perfected the design at Dayton, OH. The overall features of the simulator elements and their current status are reviewed. More detailed discussions of the quasilinear aerodynamics, vehicle dynamics, and stability augmentation systems are presented. The unstable vehicle model is validated by a novel technique to measure its frequency response under pseudo-stabilized modes of operation. Time traces are shown of manually controlled flights over a photo-realistic airfield.

I. L. Ashkenas, Twenty-Five Years of Handling Qualities Research, J. of Aircraft, Vol. 21, No. 5, pp. 289-301, 1984. (STI-P-323)This paper reflects on 25 years (or more) of handling quality research and shares with the reader some of the author's resulting experiences and thoughts. When reaching back so far and considering all that has been accomplished, there are many facets of handling or flying qualities which could be covered and considered. However, the author chooses to limit discussion to those aspects concerned with the theory of handling qualities, in turn relating to closed-loop, pilot-vehicle, frequency-domain analysis and its application to handling and flight control problems. This is not to deny other aspects of handling qualities research which are beyond the scope of this limited exposition, such as: ground and in flight simulation; rating systems; optimal control operator models; workload concepts; and data collection and codification. Rather, it is to emphasize those aspects that the author is personally most familiar with, and which stress the design guidance role of handling qualities theory and practice. This has always been important and it is especially important now because of increasing dependence on sophisticated flight control systems which can completely alter the way an airplane responds to the pilot's inputs. In fact, handling quality research has recently come up for its share of criticism as being inadequate to cope with some of today's design problems. For example, Berry, in a recent article in Astronautics and Aeronautics and Gibson, in a paper before the AGARD Conference in Fort Worth, both decried the fact that there have been a rash of generic handling problems associated with high-performance aircraft having sophisticated flight control systems, and that such systems have not always reached their full potential to provide handling qualities superior to much simpler aircraft of the past. Against this background, first to be discussed are the basic aspects of handling or flying qualities and some of the early design problems that were solved; then, the growth of handling qualities theory in response to design demands; and, finally, how that theory has been applied and expanded over the years to become a valuable tool, especially useful in coping with new situations such as those that seem to be occurring almost daily.

D. T. McRuer, The Development of Pilot-in-the-Loop Analysis, Journal of Aircraft, vol. 10, no. 9, pp. 515-524, 1972. (AIAA 72-898, STI-P-129) PILOTED aircraft, to be effectively used, have always required a satisfactory match of the aircraft characteristics (including vehicle dynamics, control manipulator, stability augmentors, displays, etc.) with the controller properties of the human pilot. An agreeable marriage is not intrinsically achieved in the design process, so the provision of proper aircraft flying qualities has often posed serious problems which the designer must solve. Until fairly recently these solutions relied very heavily on intuitive cut and-try procedures. Over the years this approach fostered many of the adventures and uncertainties of flight testing. The desire to handle aircraft stability and control problems in a more analytical fashion was recognized long ago. For example, before World War II Koppen stated: Since the controlled motion of an airplane is a combination of airplane and pilot characteristics, it is necessary to know something about both airplane and pilot characteristics before a satisfactory job of airplane design can be done. But the central difficulty in accomplishing a pilot/vehicle analysis was recognized earlier still. For example, W. Crowley and Sylvia Skan remarked in a 1930 Aeronautical Research Committee report: A mathematical investigation of the controlled motion is rendered almost impossible on account of the adaptability of the pilot. Thus if it is found that the pilot operates the controls of a certain machine according to certain laws, and so obtains the best performance, it cannot be assumed that the same pilot would apply the same laws to another machine. He would subconsciously, if not intentionally, change his methods to suit the new conditions, and the various laws possible to a pilot are too numerous for a general analysis. Actually, matters are even worse than Crowley and Skan recognized; for while much of the pilot's dynamic behavior is governed by the aircraft dynamics, many additional factors also affect his properties.

D. T. McRuer, W. F. Clement, P. M. Thompson, Ph.D., and R. E. Magdaleno, Minimum Flying Qualities. Volume II: Pilot Modeling for Flying Qualities Applications, Systems Technology, Inc., Hawthorne, CA, Technical Report, WRDC TR-89-3125, Vol. II, STI-TR-1235-01-II, August 1990.The project was initiated to explore the modern nature of minimum flying qualities in the presence of modern aircraft and multi-redundant flight control system technology. It had several phases, including: 1) an intensive effort to develop and/or elaborate existing pilot modeling analysis techniques to apply to situations associated with minimum flying qualities, divided attention pilot operations, and multi-axis control tasks; 2) preliminary analyses and associated fixed base simulations to expand the meager multi-axis data base and to serve as pilot studies for more extensive simulations on the Air Force's Large Amplitude Multimode Aerospace Research Simulator. 3) an extensive simulation program on LAMARS to investigate minimum flying qualities and related situations; and 4) analysis and interpretation of both the early and LAMARS simulation efforts in the context of the pilot modeling advances. The project documentation appears in three volumes. Volume I reports on the results of 2) through 4) above. Volume 11 is a stand-alone monograph on pilot modeling, including procedures for estimating pilot workload as 'measured' by pilot ratings. Volume III is a stand-alone monograph which presents a detailed implementation of a much expanded version of the human optimal control model on Program CC.

I. L. Ashkenas and D. T. McRuer, Optimization of the Flight-Control, Airframe System, Journal of the Aero/Space Sciences, vol. 27, no. 3, pp. 197-218, 1960. (STI-P-003)The analysis of a system composed of a flight control and an airframe is ordinarily accomplished by using servoanalysis techniques in which the airframe and controller are described in terms of transfer functions. Optimization of such a system at the analytical level involves the selection of desirable relative locations for the poles and zeros of the airframe and controller transfer functions. The appropriate airframe pole and zero locations thus selected are then reflected back into the airframe geometrical characteristics. To achieve such an optimum system thus demands an overall approach which considers both the airframe and flight controller to be alterable system elements. This paper develops the optimization concept and illustrates the procedure with practical examples.