Results 101 to 110 of about 15,084 (235)

DETERMINATION OF OPTIMAL AZIMUTH FOR MOUNTING ULTRALIGHT COAXIAL HELICOPTER BLADES

Вестник Донского государственного технического университета, 2018
The possibility of reducing vibration of the ultralight coaxial helicopter blades on the through harmonic wave by mounting blades on the optimal azimuth is shown.
Vitaly V. Dudnik, Vladimir A. Kolot
doaj  

Rotor blade design and dynamic characteristics analysis of unmanned helicopter

Hangkong gongcheng jinzhan
The widespread application of composite materials in blades also makes the force and stiffness characteristics of blades more complex than traditional blades.
GAO Hongbo
doaj   +1 more source

Calculated Dynamic Characteristics of a Soft-Inplane Hingeless Rotor Helicopter [PDF]

Calculated dynamic characteristics of a representative soft-inplane hingeless rotor helicopter are presented. The flight dynamics as a function of speed and gross weight are given. The requirements for accurate analytical modelling of this helicopter are
Johnson, W.
core   +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

Advancing-side directivity and retreating-side interactions of model rotor blade-vortex interaction noise [PDF]

Acoustic data are presented from a 40 percent scale model of the four-bladed BO-105 helicopter main rotor, tested in a large aerodynamic wind tunnel.
Elliott, J. W., Martin, R. M., Schultz, K.-J., Splettstoesser, W. R.   +3 more
core   +1 more source

A flight investigation of performance and loads for a helicopter with NLR-1T main-rotor blade sections [PDF]

Data on performance and rotor loads for a teetering-rotor, AH-1G helicopter flown with a main rotor that had the NLR-1T airfoil as the blade-section contour are presented. The test envelope included hover, forward-flight speed sweeps from 35 to 85 m/sec,
Morris, C. E. K., Jr., Stevens, D. D., Tomaine, R. L.   +2 more
core   +1 more source

Aeroacoustic analysis of main rotor and tail rotor interaction [PDF]

, 2008
The increased restrictions placed on helicopter noise levels over recent decades have encouraged manufacturers to better understand tail rotor noise and its aerodynamic sources.
Brown, R.E., Duraisamy, K., Fletcher, T.M.   +2 more
core   +1 more source

PASSIVE CONTROL OF SHOCK WAVE APPLIED TO HELICOPTER ROTOR HIGH-SPEED IMPULSIVE NOISE REDUCTION

TASK Quarterly, 2010
A strong, normal shock wave, terminating a local supersonic area on an airfoil (or a helicopter blade), not only limits the aerodynamic performance, but also becomes a source of High-Speed Impulsive (HSI) noise.
PIOTR DOERFFER, OSKAR SZULC
doaj  

Investigation of Helicopter Blade Tip Configuration during Hover Flight Employing Computational Fluid Dynamics

Modelling and Simulation in Engineering
Our research focused on investigating the influence of rotor blade tip geometry on the aerodynamic performance of helicopters during hover flight, with the goal of enhancing overall efficiency.
Soufiane Stouti, Assel Thami Lahlou, Ismail Lagrat, Hamid Mounir, Oussama Bouazaoui   +4 more
doaj   +1 more source

Results of the flight noise measurement program using a standard and modified SH-3A helicopter [PDF]

A field noise measurement program has been conducted using both a standard SH-3A helicopter and an SH-3A helicopter modified to reduce external noise levels.
Henderson, H. R., Hilton, D. A., Pegg, R. J.   +2 more
core   +1 more source