Airworthiness Considerations For Stol Aircraft

A simulator study of STOL airworthiness criteria was conducted using a model of an augmentor wing transport. This study covered the approach, flare and landing, go-around, and takeoff phases of flight. The two volumes of this report document the results of that investigation. Volume One summarizes the results and discusses possible implications with regard to airworthiness criteria. The results provide a data base for future STOL airworthiness requirements and a preliminary indication of potential problem areas. The results are also compared to the results from an earlier simulation of the Breguet 941S. Where possible, airworthiness criteria are proposed for consideration.

This report summarizes the results of a joint NASA-FAA research program directed toward development of civil airworthiness flight-criteria for power-lift transports. Tentative criteria are proposed for performance and handling characteristics for powered-lift transport aircraft in commercial service. The aircraft considered are primarily wing-supported vehicles which rely upon the propulsion system for a significant portion of lift and control. VTOL aircraft are excluded. The flight criteria treat primarily the approach and landing flight phases, because it is in these flight phases that the greatest use of powered lift is made, and the greatest differences from conventional aircraft tend to appear. Consequently, the flight task tends to become most demanding. The tentative criteria are based on simulation and flight experience with a variety of powered-lift concepts. These concepts have not employed flight director, advanced displays, or advanced augmentation systems. The tentative criteria proposed were formulated by a working group comprised of representatives of the U.S., British, French, and Canadian airworthiness authorities, as well as research personnel of the NASA and other organizations. It is recognized that more work is needed to assure general applicability of the critera. (Author).

Annotation This text presents the principles of dynamics and control for vertical, short take-off landing (V/STOL) aircraft. It is the first book of its kind. It is intended for graduate students and professionals in aeronautics who have knowledge of linear systems analysis, aircraft static, dynamic stability, and control. The text begins with a discussion of V/STOL aircraft operations. Control strategies, equations of motion, longitudinal and lateral-directional flying qualities in both hover and forward flight, wind and turbulence responses, and control augmentation and cockpit displays are covered. Specific examples of the YAV-8B Harrier and XV-15 Tilt Rotor aircraft are used to illustrate actual V/STOL dynamic and control characteristics.

A flight investigation was performed with the Dornier DO-31 VTOL to evaluate the performance, handling qualities, and operating characteristics that are considered to be important in the operation of a commercial VTOL transport in the terminal area. The DO-31, a 20,000 kilogram transport, has a mixed jet propulsion system; main engines with nozzles deflect from a cruise to a hover position, and vertical lift engines operated below 170 knots. This VTOL mode incorporates pitch and roll attitude and yaw rate stabilization. The tests concentrated on the transition, approach, and vertical landing. The mixed jet propulsion system provided a large usable performance envelope that enabled simulated IFR approaches to be made on 7 deg and 12 deg glide slopes. In these approaches management of thrust magnitude and direction was a primary problem, and some form of integrating the controls will be necessary. The handling qualities evaluation pointed out the need for additional research of define flight path criteria. The aircraft had satisfactory control and stability in hover out of ground effect. The recirculation effects in vertical landing were large below 15 meters.

This publication presents materials that constituted the lectures presented by the author as part of Course AA 234 Dynamics, Control, and Flying Qualities of V/STOL Aircraft that was taught in the Department of Aeronautics and Astronautics at Stanford University. It covers representative operations of vertical and short takeoff and landing (V/STOL) aircraft, a discussion of the pilot's strategy in controlling these aircraft, the equations of motion pertinent to V/STOL tasks, and their application in the analysis of longitudinal and lateral-directional control in hover and forward flight. Following that development, which applies to the characteristics of the basic airframe and propulsion system, the text concludes with a discussion of the contributions of control augmentation in specific flight tasks and of the integration of modern electronic displays with these controls.