Advanced Flight Tests

Course Outline

Day One

• Why such advanced tests? Basic philosophy and attitudes, overview of documents describing governing regulations, history
• Fundamental principles of aeroelasticity: description of static and dynamic aeroelastic phenomena; definitions, terminology, and assumptions; limitations of theory; flutter analysis; development of basic aeroelastic equations; interpretation of supporting analyses
• Experimental and analytical tools used in preflight preparation: modal methods, ground vibration tests and analysis, wind tunnel test techniques, interpretation of dynamically similar wind tunnel model data

Day Two

• Instrumentation for flutter envelope expansion: suitable sensors, near real-time data analysis
• Subcritical response techniques, interpretation of supporting analyses
• Interpreting test results: analyzing real-time data, postflight analysis of data
• Expanding the envelope: excitation methods, clearance to 85% flutter envelopes, example programs
• Discussions of limit cycle oscillations

Day Three

• Foundations of post-stall flight testing: definitions of stall, departure, post-stall gyrations, and spins; description of spin modes and spin phases; development of large disturbance equations of motion; idealized flight path in a spin; balance of aerodynamic and inertial forcing functions; autorotation and its causes; effect of damping derivatives; effect of mass distribution; simplification of post-stall equations of motion
• Aerodynamic conditions for dynamic equilibrium: pitching moment equilibrium, rolling and yawing moment equilibrium; design goals and trends to provide post-stall capability: agility measures of merit, unsteady lift, thrust vector control, vortex control
• Experimental tools for preflight preparation: water tunnel tests and flow visualization tools, static wind tunnel tests, dynamic wind tunnel tests, rotary balance tests

Day Four

• Instrumentation for post-stall flight tests: sensors needed and their specifications; pre-test planning and preparation: data requirements, flight test team preparation and training, flight simulation; maneuver monitoring in real time for envelope expansion
• Emergency recovery devices: types of devices available, sizing and other design constraints, validation
• Subsystem modifications for post-stall testing: additional pilot restraint devices, control system modifications, propulsion system modifications
• Recommended recovery techniques; interpreting post-stall flight test results: analyzing real-time data, postflight analysis of data

Day Five

• Guidelines and discipline for conducting advanced flight tests: test team training, incremental buildup to critical conditions, use of simulation, independent review teams
• Planning for efficiency in data collection and data management: tailoring the scope of the tests to the requirement; identifying critical parts of the envelope; combining maneuvers and integration of backup test points; using all available tools: real-time monitoring, automated inserts; shared data processing between test site and home site
• Contingency planning: attrition of resources, backup support facilities, safety guidelines and documentation; course wrap-up and critique