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Exploratory Investigation Of Aerodynamic Characteristics Of Helicopter Tail Boom Cross Section Models With Passive Venting
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Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781720520146 Total Pages :52 pages Book Rating :4.5/5 (21 download)
Book Synopsis Exploratory Investigation of Aerodynamic Characteristics of Helicopter Tail Boom Cross-Section Models with Passive Venting by : National Aeronautics and Space Administration (NASA)
Download or read book Exploratory Investigation of Aerodynamic Characteristics of Helicopter Tail Boom Cross-Section Models with Passive Venting written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-31 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two large-scale, two-dimensional helicopter tail boom models were used to determine the effects of passive venting on boom down loads and side forces in hovering crosswind conditions. The models were oval shaped and trapezoidal shaped. Completely porous and solid configurations, partial venting in various symmetric and asymmetric configurations, and strakes were tested. Calculations were made to evaluate the trends of venting and strakes on power required when applied to a UH-60 class helicopter. Compared with the UH-60 baseline, passive venting reduced side force but increased down load at flow conditions representing right sideward flight. Selective asymmetric venting resulted in side force benefits close to the fully porous case. Calculated trends on the effects of venting on power required indicated that the high asymmetric oval configuration was the most effective venting configuration for side force reduction, and the high asymmetric with a single strake was the most effective for overall power reduction. Also, curves of side force versus flow angle were noticeable smoother for the vented configurations compared with the solid baseline configuration; this indicated a potential for smoother flight in low-speed crosswind conditions.Banks, Daniel W. and Kelley, Henry L.Armstrong Flight Research Center; Langley Research CenterAERODYNAMIC CHARACTERISTICS; HELICOPTERS; STRAKES; AERODYNAMIC CONFIGURATIONS; TWO DIMENSIONAL MODELS; TAIL ASSEMBLIES; CROSS FLOW; FLIGHT CONDITIONS; WIND DIRECTION; VENTING; ASYMMETRY
Book Synopsis Exploratory Investigation of Aerodynamic Characteristics of Helicopter Tail Boom Cross-Section Models with Passive Venting by : Daniel W. Banks
Download or read book Exploratory Investigation of Aerodynamic Characteristics of Helicopter Tail Boom Cross-Section Models with Passive Venting written by Daniel W. Banks and published by . This book was released on 2000 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two large-scale, two-dimensional helicopter tail boom models were used to determine the effects of passive venting on boom down loads and side forces in hovering crosswind conditions. The models were oval shaped and trapeziodal shaped. Completely porous and solid configurations, partial venting in various symmetric and asymmetric configurations, and strakes were tested. Calculations were made to evaluate the trends of venting and strakes on power required when applied to a UH-60 class helicopter. Compared with the UH-60 baseline, passive venting reduced side force but increased down load at flow conditions representing right sideward flight. Selective asymmetric venting resulted in side force benefits close to the fully porous case. Calculated trends on the effects of venting on power required indicated that the high asymmetric oval configuration was the most effective venting configuration for side force retention, and the high asymmetric with a single strake was the most effective for overall power reduction. Also, curves of side force versus flow angle were noticeably smoother for the vented configurations compared with the solid baseline configuration; this indicated a potential for smoother flight in low-speed crosswind conditions.
Book Synopsis Aerodynamic Characteristics of Several Current Helicopter Tail Boom Cross Sections Including the Effect of Spoilers by : John C. Wilson
Download or read book Aerodynamic Characteristics of Several Current Helicopter Tail Boom Cross Sections Including the Effect of Spoilers written by John C. Wilson and published by . This book was released on 1986 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: Aerodynamic characteristics were determined of three cylindrical shapes representative of tail boom cross sections of the AH-64, UH-60, and UH-1H helicopters. Forces and pressures were measured in a wind-tunnel investigation. Data was obtained for a flow incidence range from -45 to 90 deg and a dynamic pressure range from 1.5 to 50 psf. These ranges provided data representative of full-scale Reynolds numbers and the full range of flow incidence to which these helicopter tail boom shapes would be subjected at low flight speeds. The effects of protuberances such as tail rotor drive-shaft covers and spoilers were evaluated. The data indicate that significant side loads on tail booms of helicopters can be generated and that the addition of spoilers can beneficially alter the side loads. Although an increase in vertical drag occurs, the net effect through reduction of tail rotor thrust required can be an improvement in helicopter performance. Keywords: Rotorcraft; Aerodynamics; Stability and control; Helicopters; Tail booms.
Book Synopsis Principles of Helicopter Aerodynamics with CD Extra by : Gordon J. Leishman
Download or read book Principles of Helicopter Aerodynamics with CD Extra written by Gordon J. Leishman and published by Cambridge University Press. This book was released on 2006-04-24 with total page 860 pages. Available in PDF, EPUB and Kindle. Book excerpt: Written by an internationally recognized teacher and researcher, this book provides a thorough, modern treatment of the aerodynamic principles of helicopters and other rotating-wing vertical lift aircraft such as tilt rotors and autogiros. The text begins with a unique technical history of helicopter flight, and then covers basic methods of rotor aerodynamic analysis, and related issues associated with the performance of the helicopter and its aerodynamic design. It goes on to cover more advanced topics in helicopter aerodynamics, including airfoil flows, unsteady aerodynamics, dynamic stall, and rotor wakes, and rotor-airframe aerodynamic interactions, with final chapters on autogiros and advanced methods of helicopter aerodynamic analysis. Extensively illustrated throughout, each chapter includes a set of homework problems. Advanced undergraduate and graduate students, practising engineers, and researchers will welcome this thoroughly revised and updated text on rotating-wing aerodynamics.
Book Synopsis Two-dimensional Aerodynamic Characteristics of Several Polygon-shaped Cross-sectional Models Applicable to Helicopter Fuselages by : Henry L. Kelley
Download or read book Two-dimensional Aerodynamic Characteristics of Several Polygon-shaped Cross-sectional Models Applicable to Helicopter Fuselages written by Henry L. Kelley and published by . This book was released on 1992 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Two-Dimensional Aerodynamic Characteristics of Several Polygon-Shaped Cross-Sectional Models Applicable to Helicopter Fuselages by : National Aeronautics and Space Adm Nasa
Download or read book Two-Dimensional Aerodynamic Characteristics of Several Polygon-Shaped Cross-Sectional Models Applicable to Helicopter Fuselages written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-15 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: A wind-tunnel investigation was conducted to determine 2-D aerodynamic characteristics of nine polygon-shaped models applicable to helicopter fuselages. The models varied from 1/2 to 1/5 scale and were nominally triangular, diamond, and rectangular in shape. Side force and normal force were obtained at increments of angle of flow incidence from -45 to 90 degrees. The data were compared with results from a baseline UH-60 tail-boom cross-section model. The results indicate that the overall shapes of the plots of normal force and side force were similar to the characteristic shape of the baseline data; however, there were important differences in magnitude. At a flow incidence of 0 degrees, larger values of normal force for the polygon models indicate an increase in fuselage down load of 1 to 2.5 percent of main-rotor thrust compared with the baseline value. Also, potential was indicated among some of the configurations to produce high fuselage side forces and yawing moments compared with the baseline model. Kelley, Henry L. and Crowell, Cynthia A. and Wilson, John C. Langley Research Center DA PROJ. 1L2-36003-D-313; RTOP 505-59-36-01...
Book Synopsis Wind-tunnel Investigation of Effects of Fuselage Cross-sectional Shape, Fuselage Bend, and Vertical-tail Size on Directional Characteristics of Nonoverlap-type Helicopter Fuselage Models Without Rotors by : James L. Williams
Download or read book Wind-tunnel Investigation of Effects of Fuselage Cross-sectional Shape, Fuselage Bend, and Vertical-tail Size on Directional Characteristics of Nonoverlap-type Helicopter Fuselage Models Without Rotors written by James L. Williams and published by . This book was released on 1956 with total page 736 pages. Available in PDF, EPUB and Kindle. Book excerpt: A low-speed investigatio was made in the Langley stability tunnel to determine the directional stability characteristics of tandem nonoverlap-type helicopter fuselages without rotors. The investigation consisted of a study of both bent and straight fuselages having either circular or essentially elliptical cross sections and with two vertical-tail sizes.
Book Synopsis NASA Langley Scientific and Technical Information Output 2000 by :
Download or read book NASA Langley Scientific and Technical Information Output 2000 written by and published by . This book was released on 2001 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Aerodynamic Effect of Strakes on Two-Dimensional Tail Boom Models of the Oh-58a and the Oh-58d Helicopters by : National Aeronautics and Space Adm Nasa
Download or read book Aerodynamic Effect of Strakes on Two-Dimensional Tail Boom Models of the Oh-58a and the Oh-58d Helicopters written by National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-10-22 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: During hover and low speed flight, helicopters experience significant aerodynamic forces on the tail boom caused by the wake from the main and tail rotors and by crosswinds. These effects were simulated during a study conducted in the Langley 14 by 22 Foot Subsonic Tunnel on a 136 percent scaled 2-D tail boom model with cross sections representative of those on the U.S. Army OH-58A and the OH-58D helicopters. The effects of longitudinal strakes attached to the cross sections were studied. To obtain the aerodynamic forces acting on the cross sections, the flow incidence range on the scaled models was varied from -45 to 90 degrees and the models were tested through a dynamic pressure range of 5 to 15 psf. The results of the OH-58A and the OH-58D configurations show a significant improvement at conditions which represent right sideward flight by reducing the adverse aerodynamic side force when the strakes are installed. These data were used to calculate a change in tail rotor power for the full scale flight vehicle and indicated approx. a 5 to 6 percent average savings in right sideward flight for the critical velocity range of 0 to 30 knots. Increases in the tail boom normal force were noted due to the strakes. The results indicate a potential for reducing the directional control and tail rotor thrust required in the critical hover and right sideward flight speed range with a calculated minimum increase to main rotor power required and an overall net improvement in power of 0.5 percent for both the OH-58A and OH-58D. Crowell, Cynthia A. and Kelley, Henry L. Langley Research Center DA PROJ. 1L1-62211-A-47-A; RTOP 505-61-51-10...
Author :National Aeronautics and Space Adm Nasa Publisher :Independently Published ISBN 13 :9781792670152 Total Pages :38 pages Book Rating :4.6/5 (71 download)
Book Synopsis Development in Helicopter Tail Boom Strake Applications in the Us by : National Aeronautics and Space Adm Nasa
Download or read book Development in Helicopter Tail Boom Strake Applications in the Us written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-12-31 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of a strake or spoiler on a helicopter tail boom to beneficially change helicopter tail boom air loads was suggested in the United States in 1975. The anticipated benefits were a change of tail boom loads to reduce required tail rotor thrust and power and improve directional control. High tail boom air loads experienced by the YAH-64 and described in 1978 led to a wind tunnel investigation of the usefullness of strakes in altering such loads on the AH-64, UH-60, and UH-1 helicopters. The wind tunnel tests of 2-D cross sections of the tail boom of each demonstrated that a strake or strakes would be effective. Several limited test programs with the U.S. Army's OH-58A, AH-64, and UH-60A were conducted which showed the effects of strakes were modest for those helicopters. The most recent flight test program, with a Bell 204B, disclosed that for the 204B the tail boom strake or strakes would provide more than a modest improvement in directional control and reduction in tail rotor power. Wilson, John C. and Kelley, Henry L. and Donahue, Cynthia C. and Yenni, Kenneth R. Langley Research Center NASA-TM-101496, NAS 1.15:101496, AVSCOM-TM-88-B-014 RTOP 505-61-51-10...
Book Synopsis Development in Helicopter Tail Boom Strake Applications in the US by : John C. Wilson
Download or read book Development in Helicopter Tail Boom Strake Applications in the US written by John C. Wilson and published by . This book was released on 1988 with total page 19 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spycraft written by Robert Wallace and published by Penguin. This book was released on 2008 with total page 616 pages. Available in PDF, EPUB and Kindle. Book excerpt: An insider's tour of the past half-century's espionage technologies also recounts some of the CIA's most secretive operations and how they have been performed using state-of-the-art spy instruments.
Download or read book Aeronautical Engineering written by and published by . This book was released on 1991 with total page 1036 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).
Download or read book Radar Man written by Edward Lovick and published by iUniverse. This book was released on 2010-10-07 with total page 301 pages. Available in PDF, EPUB and Kindle. Book excerpt: During the 1950s, the United States and the Soviet Union teetered on the brink of nuclear devastation. Americas hope for national security relied solely upon aerial reconnaissance. Radar Man is the fascinating memoir of a physicist who, with his colleagues, developed the stealth technology that eventually created radar-invisible aircraft. Edward Lovick shares a compelling story from the perspective of an enthusiastic scientist that highlights his pioneering experiences in an innovative, secret world as he helped create stealth aircraft such as the A-12 OXCART, SR-71 Blackbird, and F-117 Nighthawk. From the moment in 1957 when Lockheeds famous aircraft designer Clarence L. 'Kelly' Johnson invited Lovick to join his Skunk Works, Lovick details how he helped the CIA eventually perform vital, covert reconnaissance flights over Soviet-held territory during the Cold War, saved Lockheed ADPs A-12 from cancellation, and provided key design input to the SR-71 and F-117. Lovicks autobiography describing his career as an engineering physicist in the Skunk Works not only draws attention to the insurmountable challenges that accompanied the task of developing radar-invisible aircraft, but also the importance of the monumental task these young scientists fulfilledall with the hope of creating a secure future for their beloved country.
Book Synopsis The Aerodynamics of Heavy Vehicles III by : Andreas Dillmann
Download or read book The Aerodynamics of Heavy Vehicles III written by Andreas Dillmann and published by Springer. This book was released on 2015-08-19 with total page 416 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume contains papers presented at the International conference “The Aerodynamics of Heavy Vehicles III: Trucks, Buses and Trains” held in Potsdam, Germany, September 12-17, 2010 by Engineering Conferences International (ECI). Leading scientists and engineers from industry, universities and research laboratories, including truck and high-speed train manufacturers and operators were brought together to discuss computer simulation and experimental techniques to be applied for the design of more efficient trucks, buses and high-speed trains in the future. This conference was the third in the series after Monterey-Pacific Groove in 2002 and Lake Tahoe in 2007.The presentations address different aspects of train aerodynamics (cross wind effects, underbody flow, tunnel aerodynamics and aeroacoustics, experimental techniques), truck aerodynamics (drag reduction, flow control, experimental and computational techniques) as well as computational fluid dynamics and bluff body, wake and jet flows.
Download or read book NASA SP. written by and published by . This book was released on 1962 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Scientific and Technical Aerospace Reports by :
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1991 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
