Accession Number : ADP005769

Title :   Interaction between Structural Considerations and System Design in Advanced Flight Controls,

Corporate Author : MESSERSCHMITT-BOELKOW-BLOHM G M B H MUNICH (GERMANY F R) HELICOPTER AND MILIT ARY AIRCRAFT GROUP

Personal Author(s) : Sella, Franco ; Schmidinger, Gerhart

Report Date : FEB 1988

Pagination or Media Count : 19

Abstract : The performance requirement of modern combat aircraft can only be met with airframes which are naturally unstable, relying on the Flight Control System to provide the required stability. This is the main reason for the choice of Fly by Wire systems, with full authority and digital computing to allow the implementation of the complex control laws required to fulfill this FCS basic requirement. The achievement of sufficient stability margins is the primary task in the design of the FCS, followed by the need to provide good Handling Qualities. Handling criteria developed in the past have shown not to be adequate to describe correctly the behaviour of current high order systems, requiring dedicated research work to define new design criteria. Digital FBW system give the possibility of implementing new features, such as automatic protection against exceedance of given manoeuvre limits (carefree handling). These features are implemented as part of the basic flight control laws. The design loads for the structure can then be defined in terms of combination of response parameters in order to cover all the operational manoeuvres with limited margins to allow significant mass savings.

Descriptors :   *FLIGHT CONTROL SYSTEMS, STRUCTURAL ANALYSIS, AIRFRAMES, FLIGHT MANEUVERS.

Subject Categories : Flight Control and Instrumentation

Distribution Statement : APPROVED FOR PUBLIC RELEASE