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a research excitation flight system was

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recently flight tested at nasa's dryden

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flight research facility

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a nasa f-16xl aircraft served as a test

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bed

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this exciter is unique because it is a

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self-contained lightweight

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excitation system which can easily be

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strapped onto a variety of aircraft

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it is intended to be used in flight

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flutter testing to help improve data

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quality

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the system consists of a fixed vein with

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a rotating slotted cylinder at the

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trailing edge

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the slotted cylinder rotates and the

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flow is ultimately deflected upward and

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downward

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this results in a periodic lift force

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which is imparted to the aircraft at

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twice the cylinder's rotational

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the exciter vane is controlled by the

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pilot in the backseat of the f-16xl

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aircraft who sets the parameters for the

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data is telemetered to the spectral

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analysis facility where it is monitored

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in real time

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here response from the wing tips are

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monitored to find frequency and damping

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trends

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as functions of mach number and dynamic

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pressure

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the wing can be seen responding to the

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exciter veins input sweeping from 5 to

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35 hertz

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data is analyzed in the computer showing

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test points were taken between mach 0.6

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and mach 1.7 at an altitude of 30 000

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feet

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the variables in the different frequency

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sweeps were linear or logarithmic sweeps

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brain time length varying force

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frequency

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this exciter system has shown it can

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provide high quality data and improve

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flight test efficiency

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with minimal interface to aircraft

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systems future testing will continue to

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provide insight into using this system

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as a safer more effective flight flutter