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03 AIR TRANSPORTATION AND SAFETY
nisms involved in the reduction of blade-vortex interaction (BVI)
noise emissions and fuselage vibrations through 2/rev blade root
control inputs and allowed the derivation of an algorithm for online
estimation of the BVI noise emissions experienced on ground. In
combination with a closed loop control law it yields a system which
allows an automatic reduction of the rotor disturbances on the basis
of local blade surface pressure measurements. The closed loop
system can also be applied to a trailing edge flap which has been
realized and investigated in the Transonic Wind Tunnel Gottingen
(TWG) in the second part of the active/adaptive rotor development
program. The test results demonstrated the ability of a servo flap to
twist the blade to a degree which is required for rejection of the rotor
disturbances and enhancement of the rotor performance.
Author
Adaptive Control; Active Control; Blade-Vortex Interaction; Rotors;
Wind Tunnel Tests
20010067707 Deutsche Forschungsanstalt fuer Luft- und
Raumfahrt, Inst. of Structural Mechanics, Brunswick, Germany
ADAPTIVE WING MODEL FOR WIND CHANNEL TESTS
Campanile, L. F., Deutsche Forschungsanstalt fuer Luft- und
Raumfahrt, Germany; Carli, V., Deutsche Forschungsanstalt fuer
Luft- und Raumfahrt, Germany; Sachau, D., Deutsche Forschungsanstalt
fuer Luft- und Raumfahrt, Germany; Active Control Technology
for Enhanced Performance Operational Capabilities of Military
Aircraft, Land Vehicles and Sea Vehicles; June 2001, pp. 4-1 - 4-15;
In English; See also 20010067671; Original contains color
illustrations; Copyright Waived; Avail: CASI; A03, Hardcopy
The aim of this work is to realize an adaptive wind channel wing
model by means of a ‘structronic’ concept. The desired geometry
changes are achieved through the use of the structural flexibility, and
no moveable parts are required. The wind channel model presents
two active sections: the ‘bump’ section, on the upper surface of the
airfoil, and the adaptive trailing edge. The changes of the airfoil
geometry by means of these parts of the model make possible to
vary the distribution of the aerodynamic load on the wing. The
activation of the bump and of the trailing edge is realized by means
of solid state actuators. A system of about two hundred shape
memory alloy actuators is used. The actuators give here also a
contribution to the stiffness of the structure. Here the numerical
results of the FEM investigations are presented, as well as the
experimental results on the prototypes of the adaptive trailing edge
and the bump actuators.
Author
Actuators; Wind Tunnel Tests; Airfoils; Trailing Edges; Flexible
Wings
20010067717 Deutsche Forschungsanstalt fuer Luft- und
Raumfahrt, Inst. of Structural Mechanics, Brunswick, Germany
ADAPTIVE ROTOR BLADE CONCEPTS: DIRECT TWIST AND
CAMBER VARIATION
Bueter, A., Deutsche Forschungsanstalt fuer Luft- und Raumfahrt,
Germany; Ehlert, U.-C., Deutsche Forschungsanstalt fuer Luft- und
Raumfahrt, Germany; Sachau, D., Deutsche Forschungsanstalt fuer
Luft- und Raumfahrt, Germany; Breitbach, E., Deutsche Forschungsanstalt
fuer Luft- und Raumfahrt, Germany; Active Control Technology
for Enhanced Performance Operational Capabilities of Military
Aircraft, Land Vehicles and Sea Vehicles; June 2001, pp. 19-1 -
19-11; In English; See also 20010067671; Copyright Waived; Avail:
CASI; A03, Hardcopy
Applying adaptronics to helicopters has a high potential to
significantly suppress noise, reduce vibration, and increase the
overall aerodynamic efficiency. Since the interaction of nonstationary
helicopter aerodynamics and elastomechanical structural characteristics
of the helicopter blades causes flight envelope limitations,
vibration and noise, a good comprehension of the aerodynamics is
essential for the development of structural solutions to effectively
influence the local airflow conditions and finally develop a structural
concept. With respect to these considerations, this paper presents
recent investigations on two different structural concepts: the direct
twist and the camber variation concept.
Author
Structural Design; Vibration Damping; Rotors; Twisting
12
03
AIR TRANSPORTATION AND SAFETY
19990026322 Aeronautical Systems Div., Wright-Patterson AFB,
OH USA
CORROSION AND FATIGUE: SAFETY ISSUE OR ECONOMIC
ISSUE
Lincoln, John W., Aeronautical Systems Div., USA; Fatigue in the
Presence of Corrosion; March 1999; 5p; In English; See also
19990026320; Copyright Waived; Avail: CASI; A01, Hardcopy; A03,
Microfiche
Corrosion and fatigue separately have both led to serious
safety as well as economic problems. Corrosion alone, in forms such
as uniform corrosion or exfoliation, may reduce the strength of
aircraft and lead to failure. Both of these forms of corrosion may lead
also to expensive component repair or replacement. There are many
cases where corrosion alone is not significant from a safety consideration,
but is a very significant economic problem. In the case of
corrosion alone, one must judge the seriousness of this problem on
an individual basis. Nondestructive inspections have found fatigue
problems where there is essentially no influence from corrosion.
Researchers have documented many cases over the years where
the consequences were catastrophic. The results of fatigue cracking
have caused many expensive repairs and modifications to the
structure including component replacement. Fatigue often combines
synergistically with corrosion. In these cases, the term corrosion
fatigue is more appropriate. In most cases, corrosion, fatigue, or
corrosion fatigue becomes a safety consideration only when either
maintenance is not performed properly or the maintenance program
is inappropriate. Experience derived from diligent maintenance has
repeatedly shown that the operator need not compromise safety
resulting from these problems. The purpose of this paper is to
describe some experiences with corrosion, fatigue, and corrosion
and fatigue and to review some of the relative literature on this
subject.
Author
Fatigue (Materials); Corrosion; Structural Failure; Aircraft
Maintenance; Aircraft Structures; Nondestructive Tests; Inspection;
Corrosion Tests; Fatigue Tests
19990092817 National Research Council of Canada, Flight Research
Lab., Ottawa, Ontario Canada
ENHANCED AND SYNTHETIC VISION SYSTEM CONCEPT FOR
APPLICATION TO SEARCH AND RESCUE MISSIONS
Swail, Carl, National Research Council of Canada, Canada; Jennings,
Sion, National Research Council of Canada, Canada; Sensor
Data Fusion and Integration of the Human Element; February 1999,
pp. 15-1 - 15-6; In English; See also 19990092805; Copyright
Waived; Avail: CASI; A02, Hardcopy; A03, Microfiche
The Flight Research Laboratory of the National Research
Council (NRC) in cooperation with the Department of National
Defense and and industrial collaborators, Canadian Marconi Company,
and CAE electronics LTD is working to integrate new cockpit
technologies to improve mission effectiveness and system safety of
Search and REscue (SAR) missions conducted from helicopters.
Search and Rescue aircraft operate in a demanding environment,
often in remote areas, at night or in inclement weather. Cockpit
systems that reduce pilot workload and improve pilot situational
awareness can save lives when appropriately integrated into the
aircraft. NRC and partners are building an enhanced and synthetic
vision system (ESVS) to help SAR helicopter pilots complete their
missions in degraded visual environments. The ESVS will provide
SAR pilots with a real time display that mimics visual flight rules
conditions. NRC plans to integrate and evaluate a prototype system
by the year 2000. The prototype system will include a visually
coupled helmet mounted display (HMD) system, a synthetic image
generated from a terrain database, an advanced sensor and an
image fusion system. A complementary research program is underway
at NRC to investigate fundamental human-machine interface
issues relevant to the proposed prototype system.
Author
Display Devices; Enhanced Vision; Helmet Mounted Displays; Man
Machine Systems; Night; Rescue Operations; Pilot Support
Systems