Stability and Response of a Forward Mounted Servo-Flap Driven by a Sub-Servo-Tab

摘要

The objective of this research is to determine the effectiveness, stability, and response of a leading-edge servo-flap driven by its own sub-servo-tab. The servo-flap approach is currently used on Kaman helicopters. However, in that application, it is a trailing-edge servo-flap that is driven by a swashplate and mechanical linkages. This present project studies whether or not a forward mounted servo-flap is as feasible as a trailing-edge servo-flap. Possible advantages of a leading-edge servo-flap are: 1) that it develops positive lift on the flap for positive lift on the blade, thus being potentially more efficient, and 2) that it places the center of gravity forward, thus eliminating the need for heavy counter-balance in the blade to prevent bending-torsion flutter. A potential disadvantage of a leading-edge flap is that it has the potential of static divergence. Here, the disadvantage is overcome by making the leading-edge servo-flap nearly free-floating. The advantage of a sub-servo-tab on the servo-flap is that it eliminates the hydraulics, linkages, and swashplates of conventional servo-flap rotors, reduces vibrations and maintenance, and requires less control power to control the blade. Fewer parts and small electric actuators to control the rotor with increased redundancy could increase reliability in the presence of battle damage.