Understanding ducted-rotor antitorque and directional control characteristics - Part I: Steady-state simulation

ALPMAN E. , LONG L. N. , Kothmann B.

JOURNAL OF AIRCRAFT, cilt.41, sa.5, ss.1042-1053, 2004 (SCI İndekslerine Giren Dergi) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 41 Konu: 5
  • Basım Tarihi: 2004
  • Doi Numarası: 10.2514/1.3701
  • Sayfa Sayıları: ss.1042-1053


Despite decades of very successful yaw-control and antitorque applications, the aerodynamics of ducted rotors in low-power, near-edgewise flow conditions are not well understood. Motivated by phenomena discovered during the development of the RAH-66 Comanche's directional-axis control laws, a research program was initiated to use computational fluid dynamics to improve the understanding of the dynamic relationship between ducted-rotor thrust and applied collective pitch, especially when the rotor is operating in near-edgewise flight conditions. This paper is a presentation of the results of this study. Numerical solutions of the inviscid Euler equations were obtained for the flow over the Comanche fuselage with a uniform actuator disk and blade element models for the FANTAIL(TM); the main rotor is excluded in this study. The solutions were obtained by running the modified PUMA2 (Parallel Unstructured Maritime Aerodynamics) computational-fluid-dynamics code with an unstructured grid with 2.8 million tetrahedral cells. Excellent correlation between the calculations and a variety of static test data are presented and discussed. Subsequent efforts will examine the important aspects of the dynamics of the thrust response, and allow further comparisons with flight-test data.