contact nasa-langley: gary fleming email: g.a.fleming@larc.nasa

ContactNASA-Langley: Gary FlemingEmail: g.a.fleming@larc.nasa.gov

Reference: In-Flight Aeroelastic Measurement Technique Development, SPIE Optical Diagnostics for Fluids, Solids, and Combustion II, paper #5191-31, San Diego, 3-4 August 2003

In-Flight Aeroelastic Measurement Technique

Aeroelastic characterization is vital to future aerospace vehicle design,but is costly, non-routine, and requires significant setup and aircraft adaptations.

Recently a wind tunnel technique has been adapted for in-flight without these limitations

Non-Metric positioning system

Three-Axis accelerometer system

Force Positioning System

Weight Application Rod

Balance (Inside Fixture)

Attributes• Robust• Low cost*• Flexible to measurement needs*• High precision possible• Simple targeting*• Time-histories (* better than current methods)

Future capabilities• Entire flight sequence• No special targets• Control surface geometry

NASA Langley Research Center and NASA Dryden Flight Research Center(within Active Aeroelastic Wing Program)

Methodology• Extract image coordinates– Manual – Centroids– Edges or lines– Digital image correlation• Transform from image to object• Subtract out reference condition

Accomplishments• In-flight measurements on F/A-18 Research aircraft• M = 0.95 at 15,000 ft.• Spanwise wing bending• Time-histories of maneuver

Complete time-histories of aerodynamically induced twist and deflection from take-off to landing, with next-day delivery of reduced data

Long-term vision