Download or read book The Correlation of Pedal Position to Tail Rotor Power Requirement on the OH 58A written by and published by . This book was released on 2002 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Every mechanical component has a finite failure life. Excessive usage of a component may cause damage. Therefore, life determination is essential to safe operation. Replacement of mechanical components prior to the end of useful life results in higher costs of maintenance. Monitoring rotating components is not always reliable or cost effective. This thesis attempts to solve this problem for a helicopter tail rotor. The development of an algorithm to calculate the loads on a component using stationary measurements can eliminate the need for rotating measurement equipment. The purpose is to predict the tail rotor power requirement of a helicopter throughout the mission profile by using the algorithm developed. The scope of this investigation was limited to representative flight regimes based upon a survey of Bell 206 jet rangers or OH-58A derivatives operators. Flight test data were collected at University of Tennessee Space Institute (UTSI). These data were then used to correlate with the results of the algorithm model. The model incorporated helicopter blade element theory, momentum theory, fin blockage effects, inertia effects, translational velocity effects, mechanical losses and altitude density correction. The model was executed using Microsoft Excel. The model required input data including helicopter characteristics, altitude, engine shaft horsepower, velocity. Based upon these data, the tail rotor power and pedal position were calculated. The calculation results of pedal position were compared with the flight test data. The accuracy of the tail rotor power was presented in the percentage of the maximum tail rotor power. It was found that the pedal position alone was a poor indicator of tail rotor power. The modeled elements mentioned above were included and resulted in significant improvement. Based on the calculated results, this model and measured pedal positions can provide at least 90-% confidence of the tail rotor power, except at large sideslip angles. Additionally, due to the tail rotor power sensitivity to the pedal position variations, the measurement of pedal positions should be performed precisely. Based on the results of this investigation, utilizing the algorithm model for predicting tail rotor power from pedal position will result in a 90-% confidence of the tail rotor power being applied. Recommend an alternative fuselage yaw moment due to sideslip chart be used to improve sideslip data. Recommend instrumented tail rotor for tail rotor power measurements.
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...
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 Cynthia A. Crowell and published by . This book was released on 1990 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Private Helicopter Pilot Studies JAA BW written by Phil Croucher and published by Lulu.com. This book was released on 2007-10-03 with total page 396 pages. Available in PDF, EPUB and Kindle. Book excerpt: The complete syllabus for the EASA PPL(H) and for other licences too. It is intended for people who are going to progress to a professional licence, which is why it is based on an ATPL(H) distance learning course.
Download or read book The Effect of Tailboom Strakes and Vertical Fin Modifications on the Performance and Handling Qualities of OH 58 Helicopters written by and published by . This book was released on 2008 with total page 106 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Bell OH-58D helicopter is used in the armed reconnaissance role by the U.S. Army worldwide. Operations in support of this mission require the aircraft to be operated at a hover for extended periods of time at high altitude and in hot conditions. This places large demands on a power limited aircraft and increases pilot workload, especially in the pointing task so important to weapons delivery. The addition of aerodynamic modifications provides an inexpensive and effective method of reducing power required and pilot workload. An investigation was conducted to determine the effects of adding tailboom strakes and a vertical fin modification (FastFin®) to a Bell OH-58D. The effect of the combined devices on helicopter performance, vibration and handling qualities was evaluated to determine any decrease in power vs. power available (increased power margin). The strakes and modified fin were attached to the tailboom in such a manner as to alter the flow pattern of air passing over the tailboom. This change in flow pattern reduced the anti-torque requirements of the tail rotor. This in turn reduced the overall power requirement. The modified fin and strake combination reduced the vortices and turbulence at the tailboom and resulted in lower pilot workload and vibration in an out-of-ground-effect hover. This study also evaluated the effects on performance and handling characteristics of the helicopter. Testing included hover, low airspeed forward, rearward, sideward flight and level forward flight power measurements and handling qualities using modified Cooper-Harper and Vibration Assessment Rating (VAR) scales. Results showed an overall improvement in handling qualities and vibration levels at critical wind azimuth angles in low airspeed flight. For out-of-ground-effect (OGE) hover, there was also a 2-3% reduction in power required due to the improved aerodynamic efficiency of the modified fin and strake combination.
Download or read book HELICOPTER AERODYNAMICS written by RATHAKRISHNAN, E. and published by PHI Learning Pvt. Ltd.. This book was released on 2018-11-01 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is developed to serve as a concise text for a course on helicopter aerodynamics at the introductory level. It introduces to the rotary-wing aerodynamics, with applications to helicopters, and application of the relevant principles to the aerodynamic design of a helicopter rotor and its blades. The basic aim of this book is to make a complete text covering both the basic and applied aspects of theory of rotary wing flying machine for students, engineers, and applied physicists. The philosophy followed in this book is that the subject of helicopter aerodynamics is covered combining the theoretical analysis, physical features and the application aspects. Considerable number of solved examples and exercise problems with answers are coined for this book. This book will cater to the requirement of numerical problems on helicopter flight performance, which is required for the students of aeronautical/aerospace engineering.. SALIENT FEATURES • To provide an introductory treatment of the aerodynamic theory of rotary-wing aircraft • To study the fundamentals of rotor aerodynamics for rotorcraft in hovering flight, axial flight, and forward flight modes • To perform blade element analysis, investigate rotating blade motion, and quantify basic helicopter performance
Download or read book Journal of the American Helicopter Society written by American Helicopter Society and published by . This book was released on 1986 with total page 320 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Federal Register written by and published by . This book was released on 1994-08-26 with total page 1250 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to autogyros helicopters and other V STOL aircraft written by Franklin D. Harris and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Helicopter Maintenance written by Joseph Schafer and published by . This book was released on 2019-08 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book The Smell of Kerosene written by National Aeronautics and Space Administration and published by Good Press. This book was released on 2023-12-28 with total page 279 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Smell of Kerosene: A Test Pilot's Odyssey encapsulates the daring and the danger inherent in the uncharted territories of early space and aircraft testing. The collection stands as a testimonial to the evolution of aeronautics, narrating the exhilarating experiences of test pilots and their indispensable role in shaping modern aviation and space exploration. Through a compilation of memoirs, technical reports, and firsthand accounts, the anthology presents a rich tapestry of literary styles, from the methodical precision of technical writing to the deeply personal and reflective tales of peril and perseverance. This diversity underscores the anthology's broader theme - the human spirit's unyielding quest for knowledge and conquest of the skies. The contributors, primarily from the National Aeronautics and Space Administration alongside notable figures like Donald L. Mallick and Peter W. Merlin, bring a wealth of experience and insight. Their backgrounds, ranging from engineering and test piloting to aerospace history, provide a comprehensive overview of the historical and technological context of air and space exploration. Their collective narratives not only honor the legacy of the fields pioneers but also highlight the interdisciplinary nature of aeronautics, where science meets human daring. The Smell of Kerosene is a must-read for anyone fascinated by the interface between human ambition and technological progress. It offers readers a unique opportunity to engage with the personal triumphs and challenges of those who have pushed the boundaries of what was technologically possible. This anthology serves not only as an educational resource but also as a source of inspiration, urging readers to contemplate the vastness of human achievement through the prism of aeronautics and space exploration. It invites a diverse audience, from academicians to enthusiasts, to dive into the depths of this pivotal era in aerospace history.
Download or read book Fundamentals of Flight written by Richard Shepherd Shevell and published by Pearson Education India. This book was released on 1989 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeroacoustics of Flight Vehicles written by Harvey H. Hubbard and published by . This book was released on 1991 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Helicopter Theory written by Wayne Johnson and published by Courier Corporation. This book was released on 2012-03-07 with total page 1122 pages. Available in PDF, EPUB and Kindle. Book excerpt: Monumental engineering text covers vertical flight, forward flight, performance, mathematics of rotating systems, rotary wing dynamics and aerodynamics, aeroelasticity, stability and control, stall, noise, and more. 189 illustrations. 1980 edition.
Download or read book The History of the XV 15 Tilt Rotor Research Aircraft written by Martin D. Maisel and published by . This book was released on 2000 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Automatic Flight Control written by Pallet and published by John Wiley & Sons. This book was released on 1987 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is an updated edition of the well-known introduction to the principles involved in the automatic flight of fixed-wing and rotary wing aircraft. The principles are related to the systems used in the representative types of aircraft (UK and US) currently in service.
