Topic
Pitching moment
About: Pitching moment is a research topic. Over the lifetime, 3213 publications have been published within this topic receiving 38721 citations.
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TL;DR: In this article, the effects of blade and root-flexure elasticity and dynamic stall on the stability of hingeless rotor blades are investigated, and the dynamic stall description is based on the ONERA models of lift, drag, and pitching moment.
Abstract: The effects of blade and root-flexure elasticity and dynamic stall on the stability of hingeless rotor blades are investigated. The dynamic stall description is based on the ONERA models of lift, drag, and pitching moment. The structural analysis is based on three blade models that range from a rigid flap-lag model to two elastic flap-lag-torsion models, which differ in representing root-flexure elasticity. The predictions are correlated with the measured lag damping of an experimental isolated three-blade rotor; the correlation covers rotor operations from near-zero-thrust conditions in hover to highly stalled, high-thrust conditions in foward flight. That correlation shows sensitivity of lag-damping predictions to structural refinements in blade and root-flexure modeling. Moreover, this sensitivity increases with increasing control pitch angle and advance ratio. For high-advance-ratio and high-thrust conditions, inclusion of dynamic stall generally improves the correlation.
14 citations
01 Jan 2014
TL;DR: In this article, a number of methods to size the wing of a new GA aircraft are presented, including aspect ratio, taper ratio, washout, and wing incidence angle, which is the most common planform shape for lifting surfaces like wings.
Abstract: A number of methods to size the wing of a new GA aircraft are presented. The chapter begins by the presentation of handy formulation to calculate various properties of trapezoidal surfaces, which is the most common planform shape for lifting surfaces like wings and horizontal and vertical tails. This is followed by the introduction of various concepts, topics, and methods for laying out the wing planform. These include aspect ratio, taper ratio, washout, and wing incidence angle. In order to help the designer evaluate the pros and cons of typical wing planform shapes, suitable for the new aircraft, a detailed discussion follows. In addition to the large number of different geometries presented detailed information about the spanwise distribution of section lift coefficients is provided to help the designer realize their properties. Next, a number of methods to evaluate the lift and pitching moment characteristics of the wing as a 3-dimensional lifting body are provided. Then, a number of issues that have to do with wing stall characteristics and how to improve them are presented. Finally, in order to help the designer in realizing the properties of the selected wing planform and airfoils, a practical version of Prandtl’s Lifting Line Theory is presented. Despite being old, this is a sophisticated numerical method used to estimate the aerodynamic properties of the wing. A computer function, written in Visual Basic for Applications, intended for use with Microsoft Excel is presented as well, allowing the reader to get to work immediately.
14 citations
TL;DR: In this article, the leading edge-suction-parameter modulated discrete vortex method is extended to a wing with a finite span and no sweep, in order to get the development of aerodynamic coefficients with an angle-of-attack, from attached to completely detached flow conditions.
Abstract: The leading-edge-suction-parameter modulated discrete vortex method is extended to a wing with a finite span and no sweep, in order to get the development of aerodynamic coefficients with an angle-of-attack, from attached to completely detached flow conditions. A first case considering the unsteady pitching motion of a flat plate is compared with published experimental and numerical results. Then, dependence of lift, drag, and pitching moment coefficients with the angle-of-attack is discussed for a wing built on an SD7003 airfoil at a constant angle-of-attack. The three-dimensional effects on the lift coefficient curve for a completely detached wing are established.
14 citations
01 Aug 1969
TL;DR: Aerodynamic characteristics effected by parallel-staged simple aerodynamic configurations at Mach numbers of 3 and 6 were analyzed in this article. But the results were limited to a single-stage simple configuration.
Abstract: Aerodynamic characteristics effected by parallel- staged simple aerodynamic configurations at Mach numbers of 3 and 6
14 citations
01 Jan 1999
TL;DR: In this article, the authors performed aerodynamic performance calculations on ten experimental ice shapes and the corresponding ten ice shapes predicted by LEWICE 2.0. The results showed that maximum lift and stall angle can be correlated to the upper horn angle and the leading edge minimum thickness.
Abstract: Aerodynamic performance calculations were performed using WIND on ten experimental ice shapes and the corresponding ten ice shapes predicted by LEWICE 2.0. The resulting data for lift coefficient and drag coefficient are presented. The difference in aerodynamic results between the experimental ice shapes and the LEWICE ice shapes were compared to the quantitative difference in ice shape geometry presented in an earlier report. Correlations were generated to determine the geometric features which have the most effect on performance degradation. Results show that maximum lift and stall angle can be correlated to the upper horn angle and the leading edge minimum thickness. Drag coefficient can be correlated to the upper horn angle and the frequency-weighted average of the Fourier coefficients. Pitching moment correlated with the upper horn angle and to a much lesser extent to the upper and lower horn thicknesses.
14 citations