Results 21 to 30 of about 3,999 (214)

Unsteady loads for coaxial rotors in forward flight computed using a vortex particle method [PDF]

open access: yes, 2018
Recent advances in coaxial rotor design have shown benefits of this configuration. Nevertheless, issues related to rotor-head drag, aerodynamic performance, wake interference, and vibration should also be considered.
Barakos, George   +2 more
core   +1 more source

Sedimentary ancient DNA of rotifers reveals responses to 200 years of climate change in two Kenyan crater lakes

open access: yesFreshwater Biology, Volume 68, Issue 11, Page 1894-1916, November 2023., 2023
Abstract Sedimentary ancient DNA (sedaDNA) has proven to be a useful tool for palaeoenvironmental studies, but only a handful of studies exist so far for tropical regions. In this study we used sedaDNA to study the temporal succession of Brachionus spp.
Margaret Kyalo‐Omamo   +7 more
wiley   +1 more source

Effect of Blade Tip Configurations on the Performance and Vibration of a Lift-Offset Coaxial Rotor

open access: yesAerospace, 2023
This present study investigates the effect of blade tip configurations, such as the sweepback angle and anhedral angle, on the performance and hub vibratory loads for the lift-offset coaxial rotor of a 30,000-pound-class high-speed long-range utility ...
Yu-Been Lee, Jae-Sang Park
doaj   +1 more source

Interactional aerodynamics and acoustics of a hingeless coaxial helicopter with an auxiliary propeller in forward flight [PDF]

open access: yes, 2008
The aerodynamics and acoustics of a generic coaxial helicopter with a stiff main rotor system and a tail- mounted propulsor are investigated using Brown's Vorticity Transport Model.
Brown, R.E.   +3 more
core   +3 more sources

Thrust pulsation of coaxial main rotor, caused by the blades relative position

open access: yesНаучный вестник МГТУ ГА, 2020
The influence of reciprocal position of the upper rotor blades in respect to the lower rotor blades is characteristic for coaxial main rotor. It is established that the initial azimuth of the blade, for example, of the upper rotor’s which does not ...
B. S. Kritsky   +3 more
doaj   +1 more source

A rational approach to comparing the performance of coaxial and conventional rotors [PDF]

open access: yes, 2009
The merit, in terms of its efficiency and performance, of the twin, contrarotating coaxial rotor configuration over the more conventional single rotor system has long been a point of contention.
Brown, R.E., Kim, Hyo Wan
core   +1 more source

Technical Configurations of a Helicopter Type Unmanned Aerial System for Pesticide and Fertilizer Application

open access: yesСельскохозяйственные машины и технологии, 2021
It was noted that when forming the configurations of an unmanned aerial system for pesticide and fertilizer application, it is necessary to take into account the interdependence of unmanned and ground-based aerial systems.
L. A. Marchenko   +3 more
doaj   +1 more source

Propeller control strategy for coaxial compound helicopters [PDF]

open access: yesProceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering, 2018
The coaxial compound configuration has been proposed as a concept for future high-performance rotorcraft. The co-axial rotor system does not require an anti-torque device, and a propeller provides axial thrust. A well-designed control strategy for the propeller is necessary to improve the performance and the flight dynamics characteristics.
Yuan, Ye   +2 more
openaire   +3 more sources

Mars Science Helicopter Conceptual Design [PDF]

open access: yes, 2020
Robotic planetary aerial vehicles increase the range of terrain that can be examined, compared to traditional landers and rovers, and have more near-surface capability than orbiters. Aerial mobility is a promising possibility for planetary exploration as
Balaram, Jayarao   +15 more
core   +1 more source

Determination of loads in the ultralight helicopter blades

open access: yesAviation, 2023
The article describes research that was carried out on coaxial a single-seat ultralight helicopter Rotorschmiede VA-115 which is manufactured by German firm RS Helikopter GmbH.
Vitaly Dudnik
doaj   +1 more source

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