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METHOD OF OPTIMIZING SECTIONS OF A TAIL BOOM FOR A ROTARY WING AIRCRAFT

  • US 20180029702A1
  • Filed: 07/28/2017
  • Published: 02/01/2018
  • Est. Priority Date: 07/28/2016
  • Status: Active Grant
First Claim
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1. A method of optimizing sections of a tail boom for a rotary wing aircraft having at least one main rotor, the tail boom extending in a longitudinal direction, each section being defined in a plane perpendicular to the longitudinal direction by a chord between a leading edge and a trailing edge of the section, and by a maximum thickness measured perpendicularly to the chord, wherein the method comprises the following steps:

  • a step of performing studies, digital simulations, and/or tests on section profiles for a tail boom;

    a step of creating a database characterizing standard sections for a tail boom, the database having four types of standard sections for the tail boom, a first type of standard sections being symmetric and maximizing the lateral force of the tail boom, a second type of standard sections being asymmetric and maximizing the lateral force, a third type of standard sections being symmetric and minimizing the negative lift of the tail boom, and a fourth type of standard sections being asymmetric and minimizing the negative lift;

    each standard section being defined by extreme characteristic points A0, A1, A2, A3 and by intermediate characteristic points A01, A02, A11, A12, A21, A22, A31, A32, the characteristic points being defined in a secondary reference frame attached to each standard section and defined by the directions of the chord and of the maximum thickness, one unit along the abscissa axis or along the ordinate axis being equal to the chord, the extreme characteristic points A0, A1, A2, A3 belonging to an outline of the standard section, A0 being situated at the trailing edge and having coordinates (1,0), A2 being situated at the leading edge and having coordinates (0,0), the extreme characteristic points A1 and A3 forming the maximum thickness and having respective coordinates −

    t/(2.c) and t/(2.c), the intermediate characteristic points A01, A02, A11, A12, A21, A22, A31, A32 being construction points for constructing the outline of the standard section serving to define a direction of the outline of the section at each extreme characteristic point A0, A1, A2, A3;

    a step of establishing looked-for aerodynamic and structural characteristics of the tail boom in terms of lateral force and negative lift generated by the air stream from the main rotor flowing over the tail boom; and

    a step of defining the sections of the tail boom as a function of the standard sections and of the looked-for aerodynamic and structural characteristics for the tail boom in order to give precedence to minimizing the negative lift and/or to maximizing the lateral force of the tail boom.

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