Download or read book An Experimental Investigation of Helicopter Rotor Hub Fairing Drag Characteristics written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was done in the NASA 14- by 22-Foot Wind Tunnel at Langley Research Center on the parasite drag of different helicopter rotor hub fairings and pylons. Parametric studies of hub-fairing camber and diameter were conducted. The effect of hub fairing/pylon clearance on hub fairing/pylon mutual interference drag was examined in detail. Force and moment data are presented in tabular and graphical forms. The results indicate that hub fairings with a circular-arc upper surface and a flat lower surface yield maximum hub drag reduction; and clearance between the hub fairing and pylon induces high mutual-interference drag and diminishes the drag-reduction benefit obtained using a hub fairing with a flat lower surface. Test data show that symmetrical hub fairings with circular-arc surfaces generate 74 percent more interference drag than do cambered hub fairings with flat lower surfaces, at moderate negative angle of attack. Sung, D. Y. and Lance, M. B. and Young, L. A. and Stroub, R. H. Ames Research Center...
Download or read book An Experimental Investigation of Helicopter Rotor Hub Fairing Drag Characteristics written by and published by . This book was released on 1989 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Advanced Hub and Pylon Fairing Configurations to Reduce Helicopter Drag written by D. M. Martin and published by . This book was released on 1993 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of Advanced Hub and Pylon Fairing Configurations to Reduce Helicopter Drag written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-08 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: New hub and pylon fairing designs were tested on a one-fifth scale Bell Helicopter Textron Model 222 helicopter with a bearingless main rotor hub. The blades were not installed for this test. The fairings were designed by NASA and Bell Helicopter Textron under a joint program and tested in the Ames Research Center 7-by 10-Foot Wind Tunnel. All six aircraft forces and moments were measured using the tunnel scales system. Previous research has identified the integrated hub and pylon fairing approach as the most efficient in reducing helicopter drag. Three hub fairings and three pylon fairings were tested (in various combinations) resulting in a total of 16 different configurations, including the baseline helicopter model without fairings. The geometry of the new fairings is described in detail. Test results are presented in the form of plots of the six model forces and moments. The data show that model drag can be reduced by as much as 20 percent by combining a small hub fairing (that has a circular arc upper surface and a flat lower surface) integrated with a nontapered pylon fairing. To minimize drag, the gap between the lower surface of the hub and upper surface of the pylon fairing must be kept to a minimum. Results show that the aerodynamic effects of the fairings on static longitudinal and directional stability can also be important. Martin, D. M. and Mort, R. W. and Young, L. A. and Squires, P. K. Ames Research Center...
Download or read book Experimental Evaluation of the Effect of Rotation on the Aerodynamic Characteristics of Two Rotor Hub Fairing Shapes written by Peter S. Montana and published by . This book was released on 1976 with total page 71 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experiment was performed to demonstrate that the drag of rotor hub fairings for high speed helicopters is not a function of advance ratio. Two hub fairing shapes were evaluated both with and without simulated blade shanks over a range of hub advance ratios from 0.5 to infinity. It was determined that the drag coefficient (and most other coefficients) is constant for hub advance ratios greater than about 3.0. (Author).
Download or read book An Experimental Investigation of Sting support Effects on Drag and a Comparison with Jet Effects at Transonic Speeds written by Charles L. Shuford and published by . This book was released on 1958 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of the Effect of Wind Tunnel Walls on the Aerodynamic Performance of a Helicopter Rotor written by Victor M. Ganzer and published by . This book was released on 1960 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Evaluation of the Effect of Rotation on the Aerodynamic Characteristics of Two Helicopter Rotor Hub Fairing Shapes written by Peter S. Montana and published by . This book was released on 1976 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Experimental Investigation of A Helicopter Rotor Hub Flow written by David Reich and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The rotor hub system is by far the largest contributor to helicopter parasite drag and a barrier to increasing helicopter forward-flight speed and range. Additionally, the hub sheds undesirable vibration- and instability-inducing unsteady flow over the empennage. The challenges associated with rotor hub flows are discussed, including bluff body drag, interactional aerodynamics, and the effect of the turbulent hub wake on the helicopter empennage. This study was conducted in three phases to quantify model-scale rotor hub flows in water tunnels at The Pennsylvania State University Applied research lab. The first phase investigated scaling and component interaction effects on a 1:17 scale rotor hub model in the 12-inch diameter water tunnel. Effects of Reynolds number, advance ratio, and hub geometry configuration on the drag and wake shed from the rotor hub were quantified using load cell measurements and particle-image velocimetry (PIV). The second phase focused on flow visualization and measurement on a rotor hub and rotor hub/pylon geometry in the 12-inch diameter water tunnel. Stereo PIV was conducted in a cross plane downstream of the hub and flow visualization was conducted using oil paint and fluorescent dye. The third phase concentrated on high accuracy load measurement and prediction up to full-scale Reynolds number on a 1:4.25 scale model in the 48-inch diameter water tunnel. Measurements include 6 degree of freedom loads on the hub and two-component laser-Doppler velocimetry in the wake. Finally, results and conclusions are discussed, followed by recommendations for future investigations.
Download or read book An Experimental Investigation of the Effects of Blade Intermeshing on the Lift and Drag of a Helicopter Rotor written by Henry H. Tompkins and published by . This book was released on 1949 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Experimental Investigation of the Drag Mechanisms of a Helicopter Rotor in Hovering Flight written by and published by . This book was released on 1993 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt: The present paper describes an experiment in which laser velocimetric methods are employed to investigate the drag mechanisms of a helicopter rotor in hover. Emphasis is on the development of a measurement technique capable of quantifying, the contribution of rotor profile drag to total power required. The scheme devised employs a 2-D LV system to measure the axial and tangential velocity field in the vicinity of the rotor blade. Application of a combined Kutta and Momentum Equation (KME) along a closed contour surrounding the blade section provides a measure of the local sectional normal and shear forces. A detailed survey of the rotor blade's near wake region is then performed in an attempt to directly determine the streamwise, velocity deficit. Integration of the resulting velocity profiles provides a measure of the profile drag. Accuracy of the method is checked by performing measurements at conditions of very low lift and by introducing blade surface modifications which aggravate the profile drag with accompanying comparisons of the effect on sectional and global performance.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Full Scale Wind Tunnel Investigation of the Drag Characteristics of an HU2K Helicopter Fuselage written by and published by . This book was released on 1963 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analytical and Experimental Investigation of Helicopter Rotor Hover Performance and Wake Geometry Characteristics written by Anton J. Landgrebe and published by . This book was released on 1971 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Speed Wind Tunnel Test of an Unpowered High Speed Stoppable Rotor Concept in Fixed Wing Mode written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-29 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of the M85, a High Speed Rotor Concept, was conducted at the NASA Langley 14 x 22 foot Subsonic Tunnel, assisted by NASA-Ames. An unpowered 1/5 scale model of the XH-59A helicopter fuselage with a large circular hub fairing, two rotor blades, and a shaft fairing was used as a baseline configuration. The M85 is a rotor wing hybrid aircraft design, and the model was tested with the rotor blade in the fixed wing mode. Assessments were made of the aerodynamic characteristics of various model rotor configurations. Variation in configurations were produced by changing the rotor blade sweep angle and the blade chord length. The most favorable M85 configuration tested included wide chord blades at 0 deg sweep, and it attained a system lift to drag ratio of 8.4. Lance, Michael B. and Sung, Daniel Y. and Stroub, Robert H. Ames Research Center; Langley Research Center...
Download or read book An Experimental Investigation of the Flow Through a Helicopter Rotor in Forward Flight written by P. Brotherhood and published by . This book was released on 1949 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect on Helicopter Performance of Modifications in Profile drag Characteristics of Rotor blade Airfoil Sections written by F. B. Gustafson and published by . This book was released on 1944 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: Performance calculations are presented for a typical helicopter rotor in which three types of airfoil section were successively used. The types represented are the rough conventional, the smooth conventional, and the laminar-flow or low-drag sections as developed for helicopter use. The performance items covered are rotor thrust for fixed power in hovering, range and endurance at cruising speed, and power required at a relatively high forward speed. Contours showing the conditions of operation encountered by the blade section and weighting curves showing the relative importance of the various section angles of attack for specified flight conditions are included as an aid in the interpretation of the results. The calculations indicated that the use of a smooth conventional section will result in marked performance gains throughout the flight range. Definite, though smaller, additional gains in take-off weight and in range and endurance may be realized by the use of a low-drag section. At high forward speeds or at moderate forward speeds and high loadings, however, losses are indicated for the low-drag sections in contrast with the smooth conventional sections. It is demonstrated that, if these losses are to be avoided, the low-drag sections must be designed to avoid the extreme rise in drag coefficient at the higher angles of attack which is characteristic of the low-drag sections now available for use in helicopters.
