3 Rotor Track & Balance

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3 Rotor Track & Balance

Development of an innovative static rotor blade measuring test facility to be used in an improved Rotor Track and Balancing procedure

A Defence Technology Project for military rotorcraft maintenance.

The purpose of the project is to develop an innovative helicopter rotor blade static testing facility capable of measuring the properties of rotor blades, with the aim to use this information for a blade adjustment advice, prior to the dynamic Rotor Track Balancing (RTB) of the blades. The ultimate goal is to reduce the number of required flights for RTB and thus to reduce helicopter maintenance costs for Defence.

The innovative rotor blade static testing facility will measure all the blade properties that are relevant for the blade dynamic behaviour, whereas traditional static balancing only considers blade mass centre of gravity measurements and adjustments. The innovative rotor blade testing facility offers unique opportunities to take into account the actual blade geometry and elastic properties in the RTB process.

Parties involved: NLR and SPECTO Aerospace.

Timeline: March 2016-May 2019 

  • 2016 Q2

    The Boeing AH-64D Apache helicopter has been chosen as demonstration platform for the analyses.

  • 2016 Q3

    Base specifications for a static rotor blade measurement facility are available, enabling the start of the facility’s design and development.

  • 2017 Q1

    The simulation model for the calculation of the structural blade and hub loads in an isolated rotor has become available, enabling the start of the rotor balancing analyses.

  • 2017 Q2

    Simulation model for the calculation of loads and accelerations in a complete helicopter has become available, enabling analyses of the rotor track and balancing activities.

  • 2018 Q1

    A full set of the aerodynamic properties of the apache rotor blade, including the trim tab influence, has been provided which provides the input for blade aerodynamic influence on the RTB process.

  • 2018 Q2

    The properties of recently introduced ‘trailing edge wedges’ on rotor blades have been included in the flow analyses.

  • 2018 Q3

    Virtual RTB and optimisation is developed and available in the rotor simulation tool. Validation with data from operational RTB sessions can now be done.

    A new design based on latest finding of the simulation and sensitivity studies has led to a more efficient, lean and more functional design of the measuring facility. The functional design is frozen and is set to be manufactured.

  • Upcoming: 2019 Q2

    The test facility will be available and will be able to measure the relevant properties of the rotor blades in the RNLAF inventory, to support more efficient Rotor Track & Balance procedures.