Rotorwash Operational Footprint Modeling

Abstract

Abstract : Wind or rotorwash generated by rotors, ducts, or jets effect the operational suitability and utility of future Vertical Takeoff and Landing (VTOL) aircraft. As the aircraft s physical size, weight, and disk loading increases beyond the range of current systems, the risk increases that rotorwash operational impact(s) may compromise an aircraft s ability to satisfy the Warfighter's needs. Early definition of anticipated rotorwash conditions will permit an assessment of operational suitability and determine whether specific design changes are warranted and/or if acceptable operational tactics, techniques, and procedures can be established. This report documents the assessment process, environmental limits, rotorwash modeling, and output display supporting the rotorwash operational footprint model. These elements graphically combine to display the rotorwash operational impact assessment on the ground environment as contour plots or footprints. The tools developed are for the single main rotor helicopter, tandem helicopter, and tiltrotor configurations, but they can be extended to encompass additional configurations. The rotorwash operational footprint displays the effect of winds generated by rotor thrust on the surrounding environment. These footprints can be used to evaluate compliance with aircraft performance specifications, verify safe separation distances, or inform design trade studies.