Transportation
Aircraft Flutter Testing
A slogan for Dynamic Engineering Inc. (DEI) is "mobilizing minds
and materials in research and development for land, sea, air, and space."
That blend of talent and technology came together in 1972 to establish
DEI of Newport News, Virginia. The core of early work by the company was
building aircraft models for wind tunnel testing at Langley Research Center.
During his 34-year employment at Langley, Wilmer Reed gained international
recognition for his innovative research, contributions and patented ideas
relating to flutter and aeroelasticity of aerospace vehicles. In the early
1980s, Reed retired from Langley to join the engineering staff of DEI.
While at DEI, Reed recognized the need to increase the safety and minimize
the cost and hazards associated with aircraft flight flutter testing. He
thus conceived and patented the DEI Flutter Exciter, now used world wide
in flight flutter testing of new or modified aircraft designs.
| Dynamic Engineering Inc.'s Flutter Exciter
mounts at the wing tips and tail tips of an aircraft to damp out structural
vibrations. |
The Flutter Exciter system provides dynamic force input to stimulate
structural vibration modes of an aircraft in flight, and through all its
flying conditions. This innovative product generates programmed sinusoi
dal forces at controllable frequencies, amplitudes, phases and sweep durations.
By inducing these forces, structural vibrations on the aircraft can be
damped.
The DEI Flutter Exciter is controlled directly by the pilot/operator
through a digital Cockpit Control Box and Avionics Box electronics and
software. The Exciters are powered by DC servo motors through interconnecting
cables. Small fixed vanes are mounted at the wing tips and tail tips of
an aircraft.
When activated, the DEI Flutter Exciter alternately deflects the airstream
upward and downward in a rapid manner, creating a force similar to that
produced by an oscillating trailing edge flap. Because the system runs
on very little electrical power, rather than tapping into an aircraft's
hydraulic system, several benefits are realized. Among them, because the
DEI flutter components are a "strap-on" type of hardware, cost
and complexity of fitting the system on the aircraft can be lessened. The
DEI Exciter is readily adaptable to a variety of aircraft. It is effective
on all fixed wing and rotorcraft applications, from single-seater to airliner-sized
vehicles.
DEI sub-scale flutter exciters are also available to incorporate into
wind tunnel flutter models, permitting an aircraft builder to pre-qualify
a vehicle design.
In recent years, DEI used its skills to fabricate a complete set of
fan blades for the National Transonic Facility (NTF) at Langley. DEI has
applied its ideas on suspension techniques to NASA work on large, flexible
space structures. More than 1,000 tasks have been completed for Langley
alone. Employed by NASA Ames-Dryden, the employee-owned group was also
contracted to work on NASA's F-16XL flight test program.
Twenty-five years after creation, DEI has grown to several hundred employees
with $20 million in annual sales and has expanded its aerodynamic analysis
tech niques to justify its company claim: "Where imagination takes
shape."
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