Results 21 to 30 of about 21,200 (250)

Imaging and Motion Parameter Estimation of Flying Helicopter With Duo Airborne SARs in $X$-Band

IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 2022
Duo airborne synthetic aperture radars in the $X$-band are proposed to acquire images of a flying helicopter. The backscattered signals manifest entangled features attributed to the compound linear motion of fuselage and spin motion of rotors.
Chou-Wei Kiang, Jean-Fu Kiang
doaj   +1 more source

Experimental research of single - rotor helicopter unintentional yaw rotation

Научный вестник МГТУ ГА, 2020
Aviation accidents related to unintentional rotation may periodically occur while flying single-rotor helicopters. On-time and correct actions may help the pilot to find the way out of this hazardous situation.
V. V. Efimov, V. A. Ivchin, O. E. Chernigin, K. O. Chernigin   +3 more
doaj   +1 more source

Design and Determination of Aerodynamic Coefficients of a Tail-Sitter Aircraft by Means of CFD Numerical Simulation

Machines, 2022
Vertical take-off and landing (VTOL) aircraft have become important aerial vehicles for various sectors, such as security, health, and commercial sectors.
Emmanuel Alejandro Islas-Narvaez, Jean Fulbert Ituna-Yudonago, Luis Enrique Ramos-Velasco, Mario Alejandro Vega-Navarrete, Octavio Garcia-Salazar   +4 more
doaj   +1 more source

Method for Compensating Helicopter Main Rotor Signal in the Time Domain Before Constructing a Tail Rotor Radar Image

Известия высших учебных заведений России: Радиоэлектроника
Introduction. The most common helicopters are those based on a single rotor design, each with a main rotor and a tail rotor. Radar images of helicopter rotors, combined with their rotational speeds, contain information that allows the helicopter type to ...
Sergey R. Heister, Valery V. Kirichenko
doaj   +1 more source

Preliminary design of small distributed ducted electric tail rotor helicopter

Hangkong gongcheng jinzhan
To address the issues of complex transmission structure, low fault tolerance, and poor safety in traditional single-rotor helicopters with tail rotors(such as high accident rates due to tail rotor transmission system failures and collisions easily ...
LIU Chaofan, DENG Haoxuan, WANG Liangquan   +2 more
doaj   +1 more source

Main Rotor-Tail Rotor Interaction and Its Implications for Helicopter Directional Control [PDF]

Journal of the American Helicopter Society, 2008
Aerodynamic interference between the main and tail rotor can have a strong negative influence on the flight mechanics of a conventional helicopter. Significant unsteadiness in the tail rotor loading is encountered under certain flight conditions, but the character of the unsteadiness can depend on the direction of rotation of the tail rotor.
Fletcher, Timothy M., Brown, R.E.
openaire   +3 more sources

Protocol for quantifying miRNA trafficking across the endosomal membrane

FEBS Open Bio, EarlyView.
An in vitro protocol measures miRNA uptake into endosomes isolated from mammalian cell extracts, which are free of subcellular contaminants. Performed at 37 °C in the presence of ATP, it ensures the import of single‐stranded miRNA into the endosomal lumen.
Syamantak Ghosh, Kamalika Mukherjee, Suvendra N. Bhattacharyya   +2 more
wiley   +1 more source

A method for tail rotor aerodynamic force prediction under rotor interference based on coupled momentum source and blade element theory

Xibei Gongye Daxue Xuebao
Due to the influence of slip flow and wake, the tail rotor of a helicopter may produce strong unsteady aerodynamic force in its main rotor interference flow field, which may affect the helicopter control and lead to structural failure.
WEN Long, ZHAO Xu, WANG Weite, LIU Xinyuan, YU Haiyang, HE Long, HE Shun   +6 more
doaj   +1 more source

Rational Tuning of Hygroscopic Oscillation of Stacked Nanoflake Assemblies for Continuous Ambient Energy Harvesting

Advanced Materials, EarlyView.
Stacked nanoflake assembly (SNA) membranes can oscillate autonomously, offering opportunities for soft actuation and energy harvesting. This work uncovers the physical mechanism behind the sustained oscillation of SNA membranes in gradient humidity and identifies three governing dimensionless parameters, enabling rational design for optimizing SNA ...
Zijing Zhang, Jimin Fu, Gesa Zhang, Zhihua Liang, Boxun Zhang, Haimin Yao   +5 more
wiley   +1 more source

Magnetic DNA Origami Nanorotors

Advanced Materials, EarlyView.
Magnetic actuation is a powerful and broadly applicable actuation mechanism due to its programmability and compatibility with biological entities. Here we demonstrate magnetic DNA origami nanorotors (MADONAs) by assembling magnetic nanocubes on DNA origami.
Lennart J. K. Weiß, Florian Rothfischer, Yihao Wang, Christoph Pauer, Xin Yin, Kevin Lang, Rabia Amin, Thomas Tsalos, Susanne Kempter, Jan Lipfert, Tim Liedl, Friedrich C. Simmel, Joe Tavacoli, Aidin Lak   +13 more
wiley   +1 more source