Launch

A Launch procedure launches an aircraft from an STK Vehicle or STK Static Object site into the air. The aircraft's initial position and attitude are defined by the site, and the procedure can further be used to model the aircraft attaining a specific launch airspeed.

Field Description
Launch Time The launch time of the aircraft. For more information on the options available for time instances and start times, see Time Options.
Position Point The launch position of the aircraft relative to the vehicle it is launching from; click to open the Select Position Point window to choose a different reference point from the Vector Geometry Tool. Click Reset to reset the point definition to the default.
Direction Vector The launch direction of the aircraft relative to the vehicle it is launching from; click to open the Select Direction Vector window to choose a different reference vector from the Vector Geometry Tool. Click Reset to reset the direction vector definition to the default.
Attitude Mode

The attitude of the aircraft during launch; select from the following options:

  • Align with Direction Vector - the aircraft's attitude is aligned with the specified Direction Vector.
  • Hold parent attitude - the aircraft maintains the attitude of the parent vehicle at the time of launch.
  • VTOL - the aircraft launches in level flight, regardless of the attitude of the parent vehicle.
True Course Hint Enables you to compute the correct altitude and true course of the launch trajectory. If the vehicle's Direction Vector is set to Zenith, it's important to define the true course of the launch using this property.
Minimum launch airspeed Select this check box to define an airspeed objective for the procedure.
Acceleration G The acceleration of the aircraft during the launch.
Airspeed The airspeed objective; the aircraft will accelerate at the specified Acceleration G until it achieves this airspeed, at which point the procedure is completed. The specified acceleration will always be achieved at the final time T, but may not be achieved at other times.
Fuel Flow Source

The fuel flow of the aircraft during launch; select from the following options:

  • Takeoff Perf Model - uses the Takeoff performance model's setting.
  • Cruise Perf Model - uses the Cruise performance model's setting.
  • Landing Perf Model - uses the Landing performance model's setting.
  • VTOL Perf Model - uses the VTOL performance model's setting.
  • Aero/Propulsion - uses the fuel flow calculated by the aerodynamics and propulsion strategies defined in the active acceleration performance model; if the acceleration performance model is not set to calculate fuel flow, then fuel flow will not be calculated for this performance model, either.
  • Override - manually specify the fuel flow in the Override Fuel Flow field.

When performing a Launch procedure from a stationary platform or the surface, wind effects cannot be overcome and the procedure will be invalid. You should disable the wind model for the procedure in this instance.