Results 51 to 60 of about 64,260 (282)

Helicopter anti-torque system using fuselage strakes [PDF]

open access: yes, 1987
The improvement of the helicopter torque control system is discussed. At low to medium forward speeds helicopter performance is limited by the effectiveness of the means for counteracting main rotor torque and controlling sideslip airloads.
Kelley, Henry L., Wilson, John C.
core   +1 more source

The Future of Hydrogen‐Powered Aviation: Technologies, Challenges, and a Strategic Roadmap for Sustainable Decarbonization

open access: yesAdvanced Energy and Sustainability Research, EarlyView.
Hydrogen‐powered aviation offers a transformative pathway to zero‐emission flight by eliminating in‐flight CO2 emissions. Key considerations include propulsion systems (fuel cells and hydrogen combustion), cryogenic storage and insulation challenges, infrastructure and cost barriers, and supply‐chain constraints.
Mubasshira   +4 more
wiley   +1 more source

Flying control of small-type helicopter by detecting its in-air natural features

open access: yesJournal of Electrical Systems and Information Technology, 2015
Control of a small type helicopter is an interesting research area in unmanned aerial vehicle development. This study aims to detect a more typical helicopter unequipped with markers as a means by which to resolve the various issues of the prior studies.
Chinthaka Premachandra   +2 more
doaj   +1 more source

Ultra‐Efficient Kidney Stone Fragment Removal via Spinner‐Induced Synergistic Circulation and Spiral Flow

open access: yesAdvanced Intelligent Systems, EarlyView.
Leveraging spinning‐induced localized suction, the spinner device enables ultra‐efficient removal of kidney stone fragments, capturing a larger quantity of fragments from distances exceeding 20 mm. The spinner significantly improves the efficiency and effectiveness of stone fragment removal by reducing operative time, increasing stone‐free rates, and ...
Yilong Chang   +3 more
wiley   +1 more source

COMPARATIVE STUDY ON CALCULATION RESULTS OF THREE-BLADE AND X-SHAPED TAIL ROTOR AT "VORTEX RING"

open access: yesНаучный вестник МГТУ ГА, 2016
The article presents the results of numerical studies of aerodynamic characteristics of isolated three-bladed tail rotor, and X-shaped tail rotor at "vortex ring".
Y. M. Ignatkin   +3 more
doaj  

Multimodal Locomotion of Soft Robots

open access: yesAdvanced Intelligent Systems, EarlyView.
This review comprehensively surveys recent advances in multimodal locomotion within soft robotics. Typical locomotion modes are summarized and categorized. Furthermore, the underlying mechanisms enabling multimodal locomotion are discussed and classified into three primary categories: active control‐based, reconfiguration‐based, and environment ...
Zihao Yuan   +4 more
wiley   +1 more source

Helicopter low-speed yaw control [PDF]

open access: yes, 1993
A system for improving yaw control at low speeds consists of one strake placed on the upper portion of the fuselage facing the retreating rotor blade and another strake placed on the lower portion of the fuselage facing the advancing rotor blade.
Crowell, Cynthia A.   +2 more
core   +1 more source

Design Challenges to Expand the Functionality of Drones: Deformable Rotorcraft and Nature‐Inspired Flapping Drones

open access: yesAdvanced Intelligent Systems, EarlyView.
This review systematically analyzes deformable drones, including extendable, foldable, and tilting configurations, along with nature‐inspired flapping rotorcraft. By classifying deformation principles and structural mechanisms, design trade‐offs, functional capabilities, and future development potential are highlighted.
Ju‐Hee Lee   +9 more
wiley   +1 more source

Design of a Symmetrical Quad-rotor Biplane Tail-Sitter Aircraft without Control Surfaces and Experimental Verification

open access: yesMATEC Web of Conferences, 2018
This paper presents the design of a symmetrical quad-rotor biplane tail-sitter VTOL UAV (Vertical Take-off and Landing Unmanned Aerial Vehicle) which is composed of four rotors and two symmetrically mounted fixed wings.
Wang Hongyu   +5 more
doaj   +1 more source

Examining the stability derivatives of a compound helicopter [PDF]

open access: yes, 2016
Some helicopter manufacturers are exploring the compound helicopter design as it could potentially satisfy the new emerging requirements placed on the next generation of rotorcraft.
Ferguson, Kevin, Thomson, Douglas
core   +1 more source

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