Mission Performance of Different Landing Gear Types in Medium Sized Twin Engine Helicopters

Abstract

Retractable wheeled landing gears (RWLG) are standard equipment on most large helicopters above 6 tons. They offer better aerodynamics in cruise, improved passenger comfort during landing and enable taxiing compared to skids. However, they are significantly more complex, heavier and more expensive which is why skids are the norm on small to medium helicopters. This paper explores the influence of weight and aerodynamics on a medium sized helicopter using three example missions in the preliminary design software NDARC. The paper shows the steps to model the helicopter and missions in NDARC and shows the results for a reference skid gear and a reference retractable wheeled landing gear configuration. Additionally, parameter sweeps of weight and drag area of the landing gear are presented as carpet plots to show the effect of other configurations. The achievable mission range is highly dependent on landing gear weight in cases where fuel weight is limited by the MTOW. For a fixed mission range the fuel savings due to decreased aerodynamic drag of the RWLG approximately offset the higher power demand in hover and slow flight caused by the increased weight. Depending on the share of fast cruise in a mission the difference in fuel burn can range from -2% to +2%.