Results 91 to 100 of about 64,260 (282)

Rotor performance characteristics from an aeroacoustic helicopter wind-tunnel test program [PDF]

open access: yes
An investigation of helicopter rotor noise at model scale was conducted in the Langley 4 by 7 meter tunnel. The program described was the first of a planned three-phase project whose purpose was to examine the characteristic noise mechanism involved in ...
Elliott, J. W., Hoad, D. R., Orie, N. M.
core   +1 more source

Supramolecular Assemblies of Self‐Immolative Janus Dendrimers With Rapid Photodegradation Response

open access: yesSmall, EarlyView.
Self‐immolative Janus dendrimers assemble into spherical nanoparticles with solid cores. Upon irradiation, rapid end‐to‐end depolymerization triggers a unique degradation pathway from spheres to crescents within minutes, enabling on‐demand release of encapsulated cargo.
Chuanfeng Li   +3 more
wiley   +1 more source

Flight Dynamics Modeling and Verification for a Novel Compound Rotorcraft Considering Rotor/Propeller/Fuselage Aerodynamic Interference

open access: yesDrones
The flight controllability and safety of unmanned compound rotorcraft are closely related to their aerodynamic characteristics. During forward flight, complex aerodynamic interference effects arise among the rotor, propeller, wing, fuselage, and ...
Xinfan Yin   +7 more
doaj   +1 more source

Control Law Design for Twin Rotor MIMO System with Nonlinear Control Strategy

open access: yesDiscrete Dynamics in Nature and Society, 2016
Modeling of complex air vehicles is a challenging task due to high nonlinear behavior and significant coupling effect between rotors. Twin rotor multi-input multioutput system (TRMS) is a laboratory setup designed for control experiments, which resembles
M. Ilyas   +5 more
doaj   +1 more source

Development in helicopter tail boom strake applications in the US [PDF]

open access: yes
The use of a strake or spoiler on a helicopter tail boom to beneficially change helicopter tail boom air loads was suggested in the United States in 1975.
Donahue, Cynthia C.   +3 more
core   +1 more source

High‐Yield Assembly of Plasmon‐Coupled Nanodiamonds Using DNA Origami for Tuned Emission

open access: yesSmall Structures, EarlyView.
Engineering assemblies of single‐photon emitters and plasmonic elements with nanometer precision opens pathways for quantum sensing and photonics applications. A surface functionalization strategy is established for grafting DNA onto nanodiamonds, and their placement on DNA origami is optimized to achieve yields above 50%.
Niklas Hansen   +7 more
wiley   +1 more source

RESULTS OF THE FIRST MI-171A2 FLYING LABORATORY TEST PHASE

open access: yesНаучный вестник МГТУ ГА, 2016
The present publication describes the results of the first stage of the flying laboratory (Mi-171 helicopter) flight tests performed at Mil Moscow Helicopter Plant, JSC facilities. Main rotor components with blades made of polymer composite materials and
V. A. Ivchin, K. Y. Samsonov
doaj  

Monitoring active osprey nests with drones is more time efficient and less disturbing than conventional methods

open access: yesWildlife Biology, EarlyView.
Drones are used to monitor bird nesting sites at less accessible locations, such as on cliffs, human infrastructure, or within the tree canopy. While there are a growing number of studies documenting avian behavioral responses to various drones, there is a continued need to monitor taxa‐specific responses to different drone models. We explored both the
Natasha K. Murphy   +4 more
wiley   +1 more source

Measurement method for repetition frequencies of the blades of an aerial vehicle on the base of the convolution of the «secondary» modulation spectrum

open access: yesДоклады Белорусского государственного университета информатики и радиоэлектроники, 2019
A novel measurement method for repetition frequencies of the blades of an aerial vehicle (in part, helicopter's main and tail rotor) for adaptation circuits of the radar sensor with an inverse synthesis of antenna aperture is proposed.
S. R. Heister, T. T. Nguyen
doaj  

Flight investigation of the effect of tail boom strakes on helicopter directional control [PDF]

open access: yes
A joint U.S. Army/NASA flight investigation was conducted utilizing a single-rotor helicopter to determine the effectiveness of horizontally mounted tail boom strakes on directional controllability and tail rotor power during low-speed, crosswind ...
Crowell, Cynthia A.   +3 more
core   +1 more source

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