Results 61 to 70 of about 30,315 (234)

The Effect of Rotor Size on the Teeter Behavior of Two‐Bladed Wind Turbines

open access: yesWind Energy, Volume 28, Issue 11, November 2025.
ABSTRACT The rotor of a two‐bladed turbine allows the implementation of an additional degree of freedom around the rotating hub y‐axis. This idea is over 60 years old, and various research and commercial turbines have had a teeter hinge. Fatigue and extreme loads can be reduced significantly with a teeter hinge. Teetered turbines have been mainly below
Fabian Bölle né Anstock   +1 more
wiley   +1 more source

Mitigation of infusion and cure‐induced defects for thick thermosetting composites: Current challenges and future trends

open access: yesPolymer Composites, Volume 46, Issue S1, Page S9-S25, 10 September 2025.
Typical manufacturing defects and mitigation strategies in thick thermosetting composites. Abstract The composite part industry is currently dominated by thin‐section geometries. However, thick composites gain interest in many applications where monolithic parts are required, such as foils, wind mill root blades, and so forth.
Francesco Taddei   +2 more
wiley   +1 more source

Sketch of the Configuration Scheme of Two-stage Variable Speed Gear Transmission in Unmanned Helicopter Main Gearbox

open access: yesJixie chuandong, 2018
For unmanned helicopter economic cruises,main rotor speed changes could be significant. At present,the most effective method of changing the main rotor speed associated with the great speed range and low cost is a variable speed gear transmission ...
Li Zhengminqing   +4 more
doaj  

An investigation of coupling ship/rotor flowfield using steady and unsteady rotor methods

open access: yesEngineering Applications of Computational Fluid Mechanics, 2017
A coupling numerical methodology has been developed using the Navier–Stokes solver for ship/rotor flowfield simulation during the helicopter shipboard launch.
Yongjie Shi, Yi Xu, Kun Zong, Guohua Xu
doaj   +1 more source

Performance Improvement of Variable Speed Rotors by Gurney Flaps [PDF]

open access: yes, 2017
Gurney flaps are used for improving the performance of variable speed rotors. An analytical model able to predict helicopter rotor power is first presented, and the flight data of the UH-60A helicopter is used for validation. The predictions of the rotor
Barakos, George N., Dong, Chen, Han, Don
core   +2 more sources

Helicopter rotor trailing edge noise

open access: yes7th Aeroacoustics Conference, 1981
A two dimensional section of a helicopter main rotor blade was tested in an acoustic wind tunnel at close to full-scale Reynolds numbers to obtain boundary layer data and acoustic data for use in developing an acoustic scaling law and testing a first principles trailing edge noise theory. Results were extended to the rotating frame coordinate system to
R. SCHLINKER, R. AMIET
openaire   +2 more sources

Uncertainty Quantification for Nonlinear Vibration of Supercritical Drive Shaft With a Dry Friction Damper

open access: yesInternational Journal of Mechanical System Dynamics, Volume 5, Issue 3, Page 463-480, September 2025.
ABSTRACT The supercritical drive shaft is becoming increasingly popular in helicopter transmission system. Dry friction dampers are specially employed to ensure the supercritical shafts crossing the critical speed safely. Due to design tolerances, manufacturing errors and time‐varying factors, the parameters of the damper are inherently uncertain ...
Liyao Song   +4 more
wiley   +1 more source

Helicopter Landing Trajectory Optimization after Tail Rotor Control Failure in Different Collective Pitch

open access: yesXibei Gongye Daxue Xuebao, 2019
This paper studies helicopter optimal landing and control procedure after tail rotor control failure (TRCF) in different collective pitch. The optimal control problem of landing after tail rotor control failure was solved numerically by direct multiple ...

doaj   +1 more source

Designing High‐Performance, Manufacturing‐Friendly Rotor Blades for Micro Wind Turbines via Cambered Plate Airfoil Optimization

open access: yesWind Energy, Volume 28, Issue 9, September 2025.
ABSTRACT Conventional methods for manufacturing rotor blades, such as composite construction and die casting, are hindered by high costs due to expensive molds, while 3D printing often results in poor quality or high production costs with unfavorable cost‐per‐part scaling.
Moritz Burmester   +2 more
wiley   +1 more source

Design and Physical Prototyping of a Novel Braking System for a Helicopter Rotor

open access: yesDesigns, 2019
The aim of this paper was to demonstrate the improved functionality and performance of an electromechanical brake for a helicopter main rotor, which to date has been hydraulically actuated using a disc brake and caliper arrangement.
Julian D. Booker   +2 more
doaj   +1 more source

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