DIVE PLANNING AND ENERGY MANAGEMENT TECHNIQUES FOR NEGATIVE P_(S) TEST POINTS

摘要

Flutter, loads, separation, and captive flight profile flight test programs often include high-speed or high-drag negative specific excess power, P_(S), test points at the edges of a flight envelope that require diving set-ups. This paper describes dive planning and energy management techniques created and implemented to successfully execute these test points. High-speed test point set-up and execution were previously accomplished using rules of thumb that were passed from one test team to another. Detailed flight test planning was not usually accomplished for these points as limited flight test data existed for the negative-P_(S) region of most aircraft envelopes. A negative P_(S) model, accounting for variations in Mach, altitude, atmospheric temperatures, aircraft weight, and configuration, was created by extrapolating level acceleration data to the negative-P_(S) region of the envelope. This model was then used to predict aircraft energy state during the high-speed dives and the dive angle required to reach negative-P_(S) test points. This model, combined with new methods, enables the test planner to predict required dive setup conditions as well as dive recovery conditions. Additionally, this paper presents ways to implement this dive planning in flight cards and during real-time monitoring in the control room. These techniques have enabled a test conductor to ensure the aircraft will reach the test point based on dive predictions while concurrently monitoring aircraft parameters and limits. These test techniques have been successfully implemented during the planning and execution of high-speed or high-drag negative-P_(S) loads, flutter, and captive flight profile test points and have resulted in safer flight test and an increase in test point efficiency. These techniques could easily be adopted across the flight test community for high speed testing and taught at the flight test schoolhouses.