To the casual airline passenger the appearance of the Boeing 747-400 jetliner is identical to that of the older model 747-300 with the exception of the winglets. However, modifications and improvements include modern digital avionics, a 'glass' cockpit and more powerful rudder control surfaces to cope with the growth in engine thrust. The upper rudder is positioned by three parallel actuators and powered by two independent hydraulic systems. Flow control is provided by a triple tandem servo valve which maintains actuator force fight below allowable limits and synchronizes hydraulic flow to the three actuators. This paper describes the requirements, design, development, analysis and iron bird testing of some of the unique features of the upper rudder hydraulic control system. The multi-seal passed all qualification tests and has been demonstrated to be suitable for flight use in fluid systems up to 5000 psi (34,5 MPa) nominal system pressure. The ability of the multi-seal to seal radially and axially gives designers new freedom in locating ports within a manifold block in the most flexible, compact and economical way. The removability/reusability of the multi-seal is well suited to miniature components which are normally not serviceable, but may require occasional removal during maintenance operations.


    Access

    Access via TIB

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    The Boeing 747-400 upper rudder control system with triple tandem valve


    Additional title:

    Das Höhenleitwerkkontrollsystem der Boeing 747-400 mit dreifachem Tandemventil


    Contributors:
    Straub, H.H. (author) / Creswell, R. (author)

    Published in:

    Publication date :

    1991


    Size :

    10 Seiten, 17 Bilder



    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English