Grips From A/c Designing(Sizing Elevator)

Grips From A/c Designing(Sizing Elevator)

2 Posts

  • Grips from A/c designing(Sizing Elevator)-Following parameters should be optimize during sizing elevator-

    1.Elevator chord to tail ratio
    2.Elevator span to tail ratio
    3.maximum positive elevator authority
    4.Maximum negative elevator authority
    5.Aerodynamic balance
    4.mass balance

    Elevator sizing process-

    1. Layout the elevator design requirements

    2.Identify take-off rotation acceleration requirement

    3.Select elevator span

    4.Establish maximum elevator deflection to prevent flow separation

    5.Calculate the wing-fuselage lift (Lwf), aircraft drag (D) and wing-fuselage pitching moment about wing-fuselage aerodynamic center.

    6.Calculate aircraft linear acceleration during take-off rotation

    7.Calculate the contributing pitching moments during take-off rotation (i.e. aircraft weight moment (MW), aircraft drag moment (MD), engine thrust moment (MT), wing-fuselage lift moment (MLwf), wing-fuselage aerodynamic pitching moment and linear acceleration moment (Ma).

    8.Calculate desired horizontal tail lift (Lh) during take-off rotation

    9.Calculate the angle of attack effectiveness of the elevator (Ae).

    10.Determine the corresponding elevator-to-tail-chord ratio (CE/Ch)

    11.If the elevator-to-tail-chord ratio (CE/Ch) is more than 0.5, it is suggested to select an all moving tail (i.e. CE/Ch = 1)

    12.Calculate elevator effectiveness derivatives

    13.Calculate the elevator deflection required to maintain longitudinal trim at various flight conditions

    14.examine the most aft and the most forward aircraft center of gravity, as well as various aircraft speeds.

    15.
    Plot the variations of the elevator deflection versus airspeed and also versus altitude.

    16.Check whether or not the elevator deflection causes the horizontal tail to stall during take-off rotation

    17.If tail stall will be occurred during take-off rotation, the elevator must be redesigned by reducing elevator deflection and/or elevator chord.

    18.If tail stall will be occurred during take-off rotation, and none of the two elevator parameters (i.e. elevator deflection and chord) may be reduced to prevent tail stall; other aircraft components such as horizontal tail, landing gear, or aircraft center of gravity must be redesigned/relocated.

    19.Aerodynamic balance/mass balance if necessary

    20.Optimize the elevator.

    21.Calculate elevator span, elevator chord and elevator area; and then draw the top-view and side-view of the horizontal tail (including elevator) with dimensions.
  • Good info.
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