Stall and Margin System

摘要

The high speeds necessary to satisfy present day requirements for helicopter operation make it desirable to provide the pilot with a warning of impending blade stall. Accordingly, it was the purpose of this program to design, fabricate, and evaluate a retreating blade stall warning system. The principle of operation employed in the system consisted of the continuous computation of the relationship between pressure altitude, temperature, gross weight, airspeed, rotor RPM, and load factor to provide a cockpit visual indication of blade stall margin. A stick shaker warning of impending blade stall was also provided. Tests conducted on a UH-2 helicopter demonstrated that the system provided satisfactory retreating blade stall warning. It was concluded that this type of system is feasible, practical and highly desirable for high speed helicopter flight. (Author)