analysis of the gust-inducesd overspeed trends of helicopter rotors

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National Aeronautics and Space Administration, Scientific and Technical Information Office, for sale by the National Technical Information Service , [Washington], Springfield, Va
Rotors (Helicopters) -- Aerodyna
StatementJulian L. Jenkins, Jr., and William T. Yeager, Jr.
SeriesNASA technical paper ; 1213, NASA technical paper -- 1213.
ContributionsYeager, William T., United States. National Aeronautics and Space Administration. Scientific and Technical Information Office.
The Physical Object
Pagination20 p. :
ID Numbers
Open LibraryOL17647808M

Equations for analyzing the potential gust-induced overspeed tendency of helicopter rotors are presented and discussed. A parametric analysis has also been carried out to illustrate the sensitivity of rotor angular acceleration to changes in rotor lift, propulsive force, tip speed, and forward Size: KB.

Analysis of the gust-inducesd overspeed trends of helicopter rotors. [Washington]: National Aeronautics and Space Administration, Scientific and Technical Information Office ; Springfield, Va.: For sale by the National Technical Information Service, An analysis of the gust-inducesd overspeed trends of helicopter rotors / By Julian L.

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Jenkins, joint author. William T. Yeager and United States. National Aeronautics and Space Administration. Scientific and Technical Information Office.

Abstract. Issued July "AVRADCOM technical report "Includes bibliographical of. Dynamic load due to gust for helicopter rotors directly affects the structural stress and flight performance. In case of gust, it may cause the loss of trust force or the increase of deflection for rotors.

In current work, an effective coupled aeroelastic model based on a medium-deflection beam theory and a nonlinear unsteady aerodynamic model in the time domain were by: 2. Dynamic load of helicopter rotors due to gust directly affects the structural stress and flight performance for helicopters.

Based on a large deflection beam theory, an aeroelastic model for isolated helicopter rotors in the time domain is constructed. Generally speaking, the aspect ratio of a helicopter blade is large enough to employ the beam theory for most aeroelastic analysis, while for gust response, the deformation of elastic blade due to gust may be very large.

Hence, a large deflection beam model is developed to investigate suddenly gust-induced by: 1. Generally speaking, the aspect ratio of a helicopter blade is large enough to employ the beam theory for most aeroelastic analysis, while for gust response, the deformation ,alarge de ection beam model is developed to investigate suddenly gust-induced response.

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NPS ARCHIVE BURKS, J. HELICOPTER GUST RESPONSE A ROTOR FLAPPING FEEDBACK CONTROL Department of Aerospace and Mechanical Sciences Report No. 88U BY JOHN S. BURKS PRINCETON UNIVERSITY DEPARTMENT OF AEROSPACE AND MECHANICAL SCIENCES DUDLEY KNOX LIBRARY HELICOPTER GUST RESPONSE AND ROTOR FLAPPING FEEDBACK CONTROL Department.

THE PREDICTION OF HELICOPTER ROTOR HOVER PERFORMANCE USING A PRESCRIBED WAKE ANALYSIS by C. Young SUMMARY A method of calculating the performance of a helicopter rotor in the hover is presented. The method combines the downwash velocity distribution induced by a contracting spiral vortex wake with strip element.

A study was conducted to perform Gramian analysis of a shrouded rotor micro air vehicle (MAV) in hover. The controllability and disturbance rejection characteristics of an unstable shrouded rotor. 1 Notation 2 wave operator, 2= 1 c2 @2 @t2 ¡r c sound speed in quiescent medium f = 0 function that describes the source surface, e.g., a rotor blade g = ¿ ¡t+r=c H(f) Heaviside function, H(f) = 0 for f 0 ‘i components of local force intensity that acts on the fluid, ‘i = Pijnj ‘r ‘iˆri r ‘˙ iˆri M local Mach number vector of source with respect to a Cited by: Blade-Element Analysis for Rotors.

A relatively simple method of predicting the more detailed performance of a helicopter rotor is the use of Blade Element Theory.

In this method the rotor is divided into a number of independent sections along the length. At each section a force balance is applied involving 2D section lift and drag with the. An initial analysis would suggest that since brownout is a function of the rotorwash – the flow field induced by the helicopter rotor wake as it impinges on the ground – it should scale with the rotor downwash velocity, and hence the square root of disk loading (thrust/rotor area).File Size: 2MB.

Performance Analysis of the Slowed-Rotor Compound Helicopter Configuration Matthew W. Floros Raytheon ITSS Moffett Field, California Wayne Johnson Army/NASA Rotorcraft Division NASA Ames Research Center Moffett Field, California The calculated performance of a slowed-rotor compound aircraft, particularly at high flight speeds, is exam-ined.

rather than analysis errors given the intersection of the test data lines for the deg plot. At zero collective and zero shaft angle, the untwisted rotor should produce zero thrust if trimmed to zero flapping. The shaft angle tested was small, deg, so the lines should all cross near the intersection of zero collective and zero Size: KB.

The flight data of the UHA helicopter is utilized to validate the methods adopted in this work. A baseline helicopter aerodynamically approximating the UHA helicopter is used. The parameters of the baseline main and tail rotors are listed in Table 1, Table distributions of the airfoil and blade twist of the main rotor are given the performance analysis, only Cited by: The paper presents the unsteady aerodynamic analysis of helicopter rotor with a panel method based on potential flow theory.

The panel method uses the piecewise constant source and doublet singularities as a solution. This potential based panel method is founded on the Dirichlet boundary condition and coupled with the time-stepping method.

anti-torque effect of the tail rotor. HELICOPTER ROTOR SYSTEM There are four primary types of rotor systems: articulated, teetering, semi-rigid and hingeless. The articulated rotor system first appeared on the autogyros of the s and is the oldest and most widely used type of rotor system. The rotor blades in this type of system can move.

An investigation of full-scale helicopter rotors at high advance ratios and advancing tip Mach numbers (NASA technical note) Unknown Binding – January 1, by John L McCloud (Author) See all formats and editions Hide other formats and editions. The Amazon Book Review Author interviews, book reviews, editors' picks, and more.

Author: John L McCloud. Helicopter rotor blades are generally composed of solid and/or thin-walled cross-section which consists of complex geometries and various topologies such as erosion shield, skin, spar and balancing weight.

The blades are usually modeled as one-dimensional beams instead of the three-dimensional beams in static and dynamic Size: KB. Journal of Sound and Vibration () 28(1), AN INVESTIGATION OF IMPULSIVE ROTOR NOISE OF A MODEL ROTOR~ J. LEVERTON,+. AND C. AMOR Westland Helicopters Limited, Yeor'il, Somerset, England (Received 27 November ) The investigation of gust induced impulsive rotor noise was made by using a three bladed, 9 ft diameter, model by: 7.

The vertical distance from the mass center of helicopter to the rotor hub is m. The main and tail rotor power predictions are compared to the flight test data of the UHA at two weight coefficients in Figure 1 including the comparison with the data for off nominal rotor speed analysis (11% rotor speed reduction) in [5].

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Revell's last helicopter release for this year is the EC ADAC. The commonly used air rescue helicopter was completely re-tooled. parts promising modeling fun. The commonly used air rescue helicopter was completely re-tooled. parts promising modeling fun. Teetering, articulated, gimbaled, and rigid hub types are considered for a compound helicopter (rotor and fixed wing).

Stability predictions obtained using an analytical rigid flapping blade analysis, a rigid blade CAMRAD II model, and an elastic blade CAMRAD II model are compared. For the flapping blade analysis, the teetering rotor is the. “A Closed-Form Analysis of Rotor Blade FlapLag Stability 1n Hover and Low-Speed Forward Flight in Turbulent Flow”, Journal of the American Helicopter Society, Vol.

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28, No. 3, Cited by: 5. Cyclic-pitch lever -- A helicopter pilot controls the pitch, or angle, of the rotor blades with two inputs: the cyclic- and collective-pitch levers, often just shortened to the cyclic and the collective.

The cyclic, or "stick," comes out of the floor of the cockpit and sits between the pilot's legs, enabling a person to tilt the craft to either. Inspection of helicopter rotor blades with the help of guided waves and "turning modes": Experimental and finite element analysis Abstract Modern helicopter rotor blades constructed of composite materials offer significant inspection challenges, particularly at inner structures, where geometry and differing material properties and anisotropy makeCited by: 3.

The Slowed rotor principle is used in the design of some helicopters. On a conventional helicopter the rotational speed of the rotor is constant; reducing it at lower flight speeds can also reduce fuel consumption and enable the aircraft to fly more economically.

In the compound helicopter and related aircraft configurations such as the gyrodyne and winged autogyro. Downwash Helicopter Measurements behind a i2-ft diameter Rotor in the ft Wind Tunnel By R. FAIL,and R. EYRE, S. COMMUNICATED BY THE PRINCIPAL DIRECTOR OF SCIENTIFIC RESEARCH (AIR),File Size: KB.

I was watching this youtube video and I noticed that at seconds they show a coast guard helicopter rescuing a man from a ship. Whats shocking about this is that the main rotor of the helicopter seem to be going incredibly slowly and the tail rotor has completely stopped.

How was the helicopter able to stay flying with such a low rotational.Helicopter rotor blade, helicopter, helicopter rotor, rotor blade, helicopter rotor blade material, helicopter rotor blade design, helicopter rotor blade airfoil, helicopter blade design 1.

INTRODUCTION Helicopters are made in different types and shapes depending upon their purposes and required payloads. But most of them share similar parts Author: Jag Sahil Saini, Hardeep Singh.Helicopter rotor explained.

A helicopter main rotor or rotor system is the combination of several rotary wings (rotor blades) and a control system that generates the aerodynamic lift force that supports the weight of the helicopter, and the thrust that counteracts aerodynamic drag in forward flight.

Each main rotor is mounted on a vertical mast over the top of the helicopter.