The TIGER helicopter, developed as a joint venture between France and Germany, has been successfully flight-tested since April 1991. Five prototypes have chalked up more than 1700 flight hours. The TIGER main rotor is a powerful soft-inplane hingeless rotor for high controllability and agility with radial and conical elastomeric bearings (FEL concept). Starting with a brief description of theoretical prediction methods, this paper addresses the whole process of load determination: predictions, critical evaluation of flight test results, measures for load reductions. Although the aircraft showed the expected flight properties from the start of testing, load optimisation was necessary to achieve a longer service life of critical main rotor parts and to expand the flight envelope. This process is structured as follows: - Start of flight tests in April 1991. Reduction of 3/rev hub loads and tuning for low 4/rev vibrations. - Hub geometry change from a 2.5 deg blade droop angle to a central 2.5 deg precone angle to expand the load factor capability by lowering loads in lead-lag bending and the control system. The structural set-up of the blade collar area was simultaneously reinforced and simplified. - Shift of the 2nd lead-lag mode from 5.5/rev to 6/rev to reduce 4/rev torque amplitudes. - Finally, a comprehensive stress flight campaign was performed for load cycle counting (approx. 30 flight hours, approx. 1000 single flight states), where the aircraft showed its structural fitness for mission task elements according to the tailored ADS 33C. The general design goal of 6000 hours lifetime for all main rotor and control system parts (elastomeric bearings: 2500 hours) was achieved.


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    Title :

    Survey of tiger main rotor loads from design to flight test


    Additional title:

    Überblick über die Hauptrotorbelastungen des Hubschraubers TIGER vom Entwurf bis zur Flugerprobung


    Contributors:


    Publication date :

    1997


    Size :

    17 Seiten, 22 Bilder, 1 Tabelle, 12 Quellen


    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English





    Survey of TIGER Main Rotor Loads from Design to Flight Test

    Goetzfried, K. / Deutsche Gesellschaft fur Luft und Raumfahrt | British Library Conference Proceedings | 1997


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