Download or read book Preliminary Vibration Survey of a Suspended Full scale OH 6A Helicopter from 0 to 45 HZ written by John H. Harris and published by . This book was released on 1996 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efforts to establish a helicopter research program in structural dynamics at NPS were greatly enhanced when the U. S. Army donated two OH-6A light observation helicopters. One of the helicopters is reserved for ground vibration testing and dynamics research. Vibration measurements are extremely important in predicting and understanding an aircraft's dynamic behavior and durability. A comparison of a helicopters natural frequencies and those frequencies transmitted to the airframe through the rotor system can alert the designer/evaluator to possible dynamic problems. This thesis establishes a baseline vibration test program on the OH-6A helicopter for future testing and comparison to analytic models. The goal of the research is to establish natural frequencies (eigenvalues) principal mode shapes (eigenvectors), and damping characteristics of the OH-6A and to compare these values to test and analytical data obtained from the McDonnell Douglas Helicopter Company.
Download or read book Preliminary Vibration Survey of a Suspended Full Scale OH 6A Helicopter from 0 to 45 Hz written by John H. Harris and published by . This book was released on 1996-03-01 with total page 76 pages. Available in PDF, EPUB and Kindle. Book excerpt: Efforts to establish a helicopter research program in structural dynamics at NPS were greatly enhanced when the U. S. Army donated two OH-6A light observation helicopters. One of the helicopters is reserved for ground vibration testing and dynamics research. Vibration measurements are extremely important in predicting and understanding an aircraft's dynamic behavior and durability. A comparison of a helicopters natural frequencies and those frequencies transmitted to the airframe through the rotor system can alert the designer/evaluator to possible dynamic problems. This thesis establishes a baseline vibration test program on the OH-6A helicopter for future testing and comparison to analytic models. The goal of the research is to establish natural frequencies (eigenvalues) principal mode shapes (eigenvectors), and damping characteristics of the OH-6A and to compare these values to test and analytical data obtained from the McDonnell Douglas Helicopter Company.
Download or read book Masters Theses in the Pure and Applied Sciences Accepted by Colleges and Universities of the United States and Canada written by and published by . This book was released on 1996 with total page 442 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Government Reports Announcements Index written by and published by . This book was released on 1996 with total page 604 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Force Determination Sensitivities Study for Full Scale Helicopter Ground Vibration Testing written by and published by . This book was released on 1989 with total page 63 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fundamental objective of the Army's research and development efforts is to increase the reliability of the Army's air mobility force, which consists primarily of rotary-wing aircraft. Excessive vibrations have always been a problem for helicopters due to the vibratory airloads generated by the main rotor as it moves edgewise through the air. Maintenance and part replacement costs require that potential vibration problems be diagnosed as early as possible in the helicopter development and fielding cycle. A methodology known as Force Determination which was developed in the early 1970's is applicable to early diagnosis of vibration-induced problems. The objective of this program was to evaluate the limitations and accuracy of the Force Determination method. Controlled laboratory experiments and numerous sensitivity studies were performed to assess the validity of this method.
Download or read book OH 6A Propulsion System Vibration Investigation written by R. J. Sullivan and published by . This book was released on 1975 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study was made of means to improve helicopter engine/airframe vibratory interface compatibility. The study was based on the characteristics of the OH-6A helicopter and the T63 engine in order to utilize existing data to validate the methodology produced in the study. Available engine and airframe data was reviewed and used to prepare a vibration spectrum for a typical mission. Airframe mobility data was acquired during a ground shake test. A finite element model of the OH-6A airframe was prepared and was coupled to a model of the T63 engine, which was based on mobility data supplied by the engine manufacturer. The airframe and engine models were combined using a modal coupling technique, and reasonable correlation with test data was obtained. An impedance/mobility coupling technique is recommended where many flexible modes are in the frequency ranges that could be excited by main-rotor-induced vibratory forces. Based on the study, recommendations were prepared and circulated to engine manufacturers for future engine vibration specification, vibration parameter selection, and data reduction. The results of the survey and the proposed recommendations are presented.
Download or read book Application of Higher Harmonic Blade Feathering on the OH 6A Helicopter for Vibration Reduction written by F. K. Straub and published by . This book was released on 1986 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Vibration and Acoustic Environment of OH 6A Helicopter Configured with and Using the XM 27 Armament System written by and published by . This book was released on 1975 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vibration and acoustic measurements were made on an OH-6A helicopter equipped with a XM-27 armament system to determine the vibration and acoustic environment throughout the vehicle. Tape recordings from 60 accelerometers and 11 microphones were made during all flight conditions including gunfire. Spectrum analyses were performed to obtain vibratory double amplitude, acceleration power spectral density, and sound pressure level, versus frequency. Amplitude probability density plots are included. Measured vibration and acoustic data are compared with military standards and specification requirements.
Download or read book U S Army H 25 Helicopter Drop Test 22 October 1960 written by James William Turnbow and published by . This book was released on 1961 with total page 63 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 A History of Army Aviation 1950 1962 written by Richard P. Weinert and published by www.Militarybookshop.CompanyUK. This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: U.S. Army aviation expanded dramatically in both size and breadth of activities after its inception in 1942, but much of its post-World War II history, particularly after the establishment of the Air Force as an independent service by the national Security Act of 1947, has been relatively neglected. Despite a certain amount of jockeying for position by both services, particularly in the early years after their separation, the Army was able to carve out a clear transport and operational combat role for its own air arm. "A History of Army Aviation - 1950-1962" examines the development of the Army's air wing, especially for air support of ground troops, both in terms of organization and in relation to the ongoing friction with the Air Force. After describing the rapid expansion of purely Army air power after 1950 and the accompanying expansion of aviation training, the book delves into the reorganization of aviation activities within a Directorate of Army Aviation. It also provides a valuable account of the successful development of aircraft armament, perhaps the most significant advance of this period. In particular, intensive experimentation at the Army Aviation School led to several practical weapons systems and helped to prove that weapons could be fired from rotary aircraft. This arming of the helicopter was to have a profound effect on both Army organization and combat doctrine, culminating in official approval of the armed helicopter by the Department of the Army in 1960. "A History of Army Aviation - 1950-1962" also explores the development of new aircraft between 1955 and 1962, including the UH-1 medical evacuation, transport, and gunship helicopter and the HC-1 cargo copter. In addition, the book discusses the Berlin Crisis of 1961 as an impetus for immediate and unexpected expansion of army aviation, quickly followed by the beginnings of intervention in Vietnam by the end of 1962.
Download or read book Rotordynamics of Turbomachinery written by John M. Vance and published by John Wiley & Sons. This book was released on 1991-01-16 with total page 404 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describes the rotordynamic considerations that are important to the successful design or troubleshooting of a turbomachine. Shows how bearing design, fluid seals, and rotor geometry affect rotordynamic behavior (vibration, shaft whirling, bearing loads, and critical speeds), and describes two successful computational methods for rotordynamic analysis in terms that can be understood by practicing engineers. Gives descriptive accounts of the state of the art in several areas of the field and presents important mathematical or computational concepts, describing equations and formulas in physical terms for better understanding. Also offers tips for troubleshooting unstable machines and provides practical interpretations of vibration measurements.
Download or read book Flight Stability and Automatic Control written by Robert C. Nelson and published by WCB/McGraw-Hill. This book was released on 1998 with total page 441 pages. Available in PDF, EPUB and Kindle. Book excerpt: The second edition of Flight Stability and Automatic Control presents an organized introduction to the useful and relevant topics necessary for a flight stability and controls course. Not only is this text presented at the appropriate mathematical level, it also features standard terminology and nomenclature, along with expanded coverage of classical control theory, autopilot designs, and modern control theory. Through the use of extensive examples, problems, and historical notes, author Robert Nelson develops a concise and vital text for aircraft flight stability and control or flight dynamics courses.
Download or read book Marines and Helicopters 1962 1973 written by Usmc Lieutenant Colonel William Fails and published by CreateSpace. This book was released on 2014-06-06 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: This history traces the development of helicopters in the Marine Corps from 1962 to 1973 and is the second in a series of two volumes which between them cover the story of Marines and helicopters from 1946 to the present. In the period covered by this volume, the Marines at last acquired helicopters fully capable of carrying out an amphibious vertical assault, and they further elaborated their helicopter doctrines and tactics. In the Vietnam war, pilots and machines met and surmounted the test of actual combat. The documentary basis for this monograph was primarily the official records of the Marine Corps and Navy Department, but considerable use was made of interviews and correspondence with key individuals involved in all phases of helicopter development. One of the most pervasive characteristics of man is hindsight. It masquerades under many guises: Mon day morning quarterbacking, second guessing, and historical writing. When viewed through time, the past becomes distorted. Problems seem simpler, the choices more clear, and the conditions less complex than those of the present. The men who played a part become more heroic or more villainous than they were in life. This volume is an attempt to portray accurately the difficulties faced and the obstacles conquered by the men who developed helicopters in the Marine Corps, so that the Marines of today and the future may meet the challenges of their own times with the same dedication as their predecessors. The men who developed helicopters in the Marine Corps had nothing more to rely on than their knowledge of what had preceded them, intelligence liberally used, and both mental and physical courage. The present-day Marine will be well served if he applies nothing more.
Download or read book Onsite Wastewater Treatment Systems Manual written by and published by . This book was released on 2002 with total page 378 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This manual contains overview information on treatment technologies, installation practices, and past performance."--Introduction.
Download or read book Rotorcraft Aeromechanics written by Wayne Johnson and published by Cambridge University Press. This book was released on 2013-04-29 with total page 949 pages. Available in PDF, EPUB and Kindle. Book excerpt: A rotorcraft is a class of aircraft that uses large-diameter rotating wings to accomplish efficient vertical take-off and landing. The class encompasses helicopters of numerous configurations (single main rotor and tail rotor, tandem rotors, coaxial rotors), tilting proprotor aircraft, compound helicopters, and many other innovative configuration concepts. Aeromechanics covers much of what the rotorcraft engineer needs: performance, loads, vibration, stability, flight dynamics, and noise. These topics include many of the key performance attributes and the often-encountered problems in rotorcraft designs. This comprehensive book presents, in depth, what engineers need to know about modelling rotorcraft aeromechanics. The focus is on analysis, and calculated results are presented to illustrate analysis characteristics and rotor behaviour. The first third of the book is an introduction to rotorcraft aerodynamics, blade motion, and performance. The remainder of the book covers advanced topics in rotary wing aerodynamics and dynamics.
Download or read book Aerodynamics of V STOL Flight written by Barnes Warnock McCormick and published by Courier Corporation. This book was released on 1999-01-01 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: An extremely practical overview of V/STOL (vertical/short takeoff and landing) aerodynamics, this volume offers a presentation of general theoretical and applied aerodynamic principles, covering propeller and helicopter rotor theory for both the static and forward flight cases. Both a text for students and a reference for professionals, the book can be used for advanced undergraduate or graduate courses. Numerous detailed figures, plus exercises. 1967 edition. Preface. Appendix. Index.
