An investigation into the cause of the unacceptably high incidence of fatigue failure of blades in the engine cooling fan fitted to Sioux helicopters led to a search for resonant frequencies of the fan blades. Tests on a stationary fan and in a rotating rig showed resonant vibration at various fan speeds; in particular, high stresses were generated by a second shaft order resonance close to the normal operating speed. A modification to overcome the problem was proposed, consisting of a stainless steel shroud fitted over the blade tips. Tests showed that this modification reduced stresses to a negligible level, and the mechanical soundness of the scheme was confirmed by an endurance run followed by an overspeed test. The modified fan was fitted to a helicopter and measurements comparing its cooling performance with a standard fan showed only small differences.


    Access

    Access via TIB

    Check availability in my library


    Export, share and cite



    Title :

    Vibration investigation of helicopter engine cooling fan


    Additional title:

    Schwingungsuntersuchung am Kuehlgeblaese fuer einen Hubschraubermotor


    Contributors:
    Swansson, N.S. (author) / Duke, G.A. (author)

    Published in:

    Publication date :

    1977


    Size :

    19 Seiten


    Type of media :

    Report


    Type of material :

    Print


    Language :

    English




    Helicopter engine cooling

    Currie, A. | Engineering Index Backfile | 1947


    HELICOPTER TYPE AIRCRAFT ENGINE LIQUID COOLING SYSTEM

    ZINNUROV NAIL RAMILEVICH / YARMUSHEV RAFAEL AZATOVICH / ARSENTEV DMITRIJ ALEKSANDROVICH et al. | European Patent Office | 2020

    Free access

    Helicopter vibration

    Prouty, W.R. | Tema Archive | 1988