Sensitivity analysis of rudder horn balance of a twin engine transport aircraft to reduce pedal force.

Rudder is one of a primary flight control surface of an aircraft and have the function as directional control and directional trim. For multi-engine aircraft, critical function of the rudder is to be able to maintain aircraft direction in case of one engine inoperative. Due to aerodynamic load, the higher rudder deflection the higher hinge moment acting on the rudder. For the aircraft equipped with mechanical control system, load on the rudder can be feel by the pilot on the pedals. Excessive load received by the pilot in long duration of operation can make tired the pilot. Maximum load on the rudder allowed by regulation in VMCG with OEI is limited to 150 lbf. Current design of the rudder still produce load higher than limit value, even aerodynamic balance e.g., servo tab and rudder horn has been implemented. Sensitivity study of rudder horn balance was carried out to improve rudder hinge moment to reduce pedal force. This study was conducted by means wind tunnel testing in the NLST in Bandung, West Java. 6 rudder horn balance model was tested, the result are compared including basic or current horn design. Horn 8 provide the best result compared to basic horn and other modified horn, it is meet requirements both for load limit of 150 lbf and safety aspect. [ABSTRACT FROM AUTHOR]