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.


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    Titel :

    Vibration investigation of helicopter engine cooling fan


    Weitere Titelangaben:

    Schwingungsuntersuchung am Kuehlgeblaese fuer einen Hubschraubermotor


    Beteiligte:
    Swansson, N.S. (Autor:in) / Duke, G.A. (Autor:in)

    Erschienen in:

    Erscheinungsdatum :

    1977


    Format / Umfang :

    19 Seiten


    Medientyp :

    Report


    Format :

    Print


    Sprache :

    Englisch




    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. | Europäisches Patentamt | 2020

    Freier Zugriff



    Helicopter vibration

    Prouty, W.R. | Tema Archiv | 1988