Design and Sizing of High-Speed Compound Rotorcraft

Abstract

High-speed configurations are among the new emerging concepts that are currently expanding the scope of rotorcraft design. Especially in the field of defense technology research, the capability of a substantial increase of maximum velocity becomes more interesting. The NATO project NGRC is considering this capability. DLR supports these activities by its continuing defense technology research. In this study the benefits and drawbacks of a high-speed capability for a given mission scenario is analyzed. For a contemporary reference configuration, a NATO generic rotorcraft has been modelled featuring a maximum take-off mass of about 10t and a maximum velocity of 82 m/s (160 KTAS). The reference was analyzed in order to derive a set of design requirement for the rotorcraft available. These requirements were also applied to the high-speed rotorcraft, except the maximum velocity was increase about 50% to 125 m/s (242 KTAS). All tasks in this study are conducted with DLRs integrated design environment IRIS. The high-speed configuration features an off-loaded main rotor, a wing, a propeller and a reduction of the rotational speed of the drive train for the extended flight envelope. Sizing has been conducted leading to an apparent increase of design mass. The reference configuration, as well as the high-speed rotorcraft were compared, with the focus on characteristics and flight performance.