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Review of Dynamic Testing SBIR Results
Modern
high-performance aircraft continue to push the flight envelope into
the high angle-of-attack regime where highly dynamic motions such as
post-stall departures and large-rate out-of-control motions are encountered.
During such motions, dynamic aerodynamic terms become large and so the
ability to simulate these motions ultimately depends on the accuracy
of measured dynamic aerodynamic forces and moments. Much of the existing
body-axis dynamic data utilized in aircraft simulations has been measured
using techniques based on assumed linearity at low angular rates and
low angles-of-attack. Thus, simulation of these motions forces extrapolation
of this data beyond its range of applicability.
An
improved forced-oscillation test technique developed by Bihrle through
a Navy funded SBIR (Small-Business Innovative Research Program) effort,
is applicable over a wide range of body-axis angular rates, angles-of-attack,
and angles-of-sideslip. The technique utilizes the "Specific Point"
data reduction method to determine force and moment coefficients at
specific angular rates, producing tabular data that captures non-linear
rate effects. In order to reduce the impact of unrealistic unsteady
flow effects on the dynamic data, the use of test motion amplitudes
and frequencies that are more representative of actual aircraft motions
is encouraged.
New reduction methodology is more general, more flexible, and more accurate than other methods, allowing Bihrle to provide customers with data products specific to their needs. Also, innovations in dynamic surface pressure visualization and exploration of test trajectory effects made
possible by new technique. The improved test methods will provide higher fidelity air vehicle simulations from the earliest stages of vehicle development that will lead to accurate representations of departure and out-of-control flight motions leading to increased flight test safety and
better pilot training.
Other Dynamic Testing Success Stories
Boeing T-45 Goshawk Inverted
Spin/Spiral Mode and Hinge Moment Testing
General
Aviation Configuration Development Support
Boeing
F/A-18E/F Super Hornet Static/Dynamic Testing and Database Development
