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Flight Test Evaluation Of Oh 58a Tailboom Failure During Autorotation Landings
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Book Synopsis Flight Test Evaluation of OH-58A Tailboom Failure During Autorotation Landings by : Thomas L. Sanders
Download or read book Flight Test Evaluation of OH-58A Tailboom Failure During Autorotation Landings written by Thomas L. Sanders and published by . This book was released on 1973 with total page 61 pages. Available in PDF, EPUB and Kindle. Book excerpt: A flight program was initiated in September 1971 to investigate the causes of the model OH-58A tailboom failures occurring in service and to explore methods of eliminating this type of failure. From the results of this test it is concluded that the tailboom failures would not have occurred had proper autorotative techniques been observed.
Book Synopsis Ground Vibration Test of OH-58A Tailboom Failure During Autorotation Landings by : D. R. Baker
Download or read book Ground Vibration Test of OH-58A Tailboom Failure During Autorotation Landings written by D. R. Baker and published by . This book was released on 1974 with total page 57 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains the results of a ground tiedown and flight test to investigate OH58A tailboom buckling failures. Tailboom damage incurred during autorotation landings could not be duplicated in the ground vibration test with the techniques employed and available equipment. (Author).
Book Synopsis OH-58A Autorotational Evaluation by : Joseph C. Watts
Download or read book OH-58A Autorotational Evaluation written by Joseph C. Watts and published by . This book was released on 1972 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: Several recent instances of tail-boom buckling have occurred after an autorotational touchdown in the OH-58A helicopter. These occurrences prompted the US Army Aviation System Command (AVSCOM) light observation helicopter (LOH) Project Manager to enter into a product improvement program (PIP) with Bell Helicopter Company (BHC) to define the problem and recommend a solution. This PIP task included computer studies, a shake test, and flight testing of a structurally instrumented OH-58A helicopter. The results of the PIP task, to date, indicate that the tail-boom buckling resulted from a resonant condition between the main rotor and the natural frequencies of the fore and aft pylon mode and the tail boom. This resonant frequency, 5 hertz, was likely to occur at high blade angles (100-percent collective) and low rotor speed (150 rpm) and was associated with large main rotor flapping excursions. Three solutions were considered: (1) change the natural frequencies of the fore and aft pylon mode and/or tail boom, (2) damp the pylon movement, and (3) eliminate the excessive blade flapping. The BHC chose the third solution by electing to restrict the maximum collective control travel which would, in turn, eliminate excessive flapping at low rotor speeds. The BHC testing showed that there was no degradation of helicopter performance as the result of the installation of an 80-percent collective pitch restriction device.
Book Synopsis Government Reports Announcements & Index by :
Download or read book Government Reports Announcements & Index written by and published by . This book was released on 1977-05 with total page 1138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Government Reports Annual Index by :
Download or read book Government Reports Annual Index written by and published by . This book was released on 1978 with total page 922 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sections 1-2. Keyword Index.--Section 3. Personal author index.--Section 4. Corporate author index.-- Section 5. Contract/grant number index, NTIS order/report number index 1-E.--Section 6. NTIS order/report number index F-Z.
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 1977 with total page 1110 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...
Book Synopsis Correlation of Results of an OH-58A Helicopter Composite Tail Boom Test with a Finite Element Model by : Nick Calapodas
Download or read book Correlation of Results of an OH-58A Helicopter Composite Tail Boom Test with a Finite Element Model written by Nick Calapodas and published by . This book was released on 1985 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: The results of testing an OH-58A composite tail boom and comparing its static and dynamic characteristics with those obtained from finite element analyses are presented in this report. Static load versus deflection data were used to verify the stiffness representation of the finite element model. Ground vibration test data were used to evaluate frequency and modal responses obtained from analysis. Discussions of each test configuration, including data analysis methodology and correlation results, are presented. Differences between measured static deflections and finite element analysis calculated deflections range from 6 to 12 percent. Natural frequency differences between test and analysis were less than 5 percent for the first and second elastic modes. Problems encountered during the testing and the impact on correlation are also discussed. Keywords: Helicopter; Composite; Primary structure; Finite element; Modeling; Correlation.
Book Synopsis Handling Qualities Evaluation of the OH-58A Helicopter Incorporating the Model 570B Three-axis Stability and Control Augumentation System by : Raymond B. Smith
Download or read book Handling Qualities Evaluation of the OH-58A Helicopter Incorporating the Model 570B Three-axis Stability and Control Augumentation System written by Raymond B. Smith and published by . This book was released on 1973 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: A limited handling qualities evaluation of the OH-58A helicopter with a Bell Helicopter Model 570B three-axis stability and control augmentation system installed was conducted to determine its capability to perform instrument flight. Testing was performed by the US Army Aviation Systems Test Activity at Edwards Air Force Base, California. The testing consisted of 25 productive flight hours and was conducted from September through November 1972. The evaluation revealed significant improvements in the aircraft handling qualities with the addition of the augmentation system. The most significant enhancing characteristics provided by the equipment were: (1) increased damping of the lateral-directional oscillation (Dutch roll), (2) improvement of aircraft spiral stability from neutral to convergent, and (3) reduction in pilot effort required to maintain trim flight conditions. This evaluation was of limited scope, and primarily addressed handling qualities. It did not provide a basis to qualify the aircraft for instrument flight.
Book Synopsis Flight Test Report of the Model OH-58A Helicopter with the 206-706-129-1 High Tubular Skid Gear Kit Installed by : Thomas L. Sanders
Download or read book Flight Test Report of the Model OH-58A Helicopter with the 206-706-129-1 High Tubular Skid Gear Kit Installed written by Thomas L. Sanders and published by . This book was released on 1972 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report contains the results of a flight test evaluation conducted on the 206-706-129-1 high skid gear as installed on the model OH58A Helicopter. An L2700-206 HS ski kit, manufactured by Airglas Engineering Company was also installed on the high skid gear and evaluated. The limitations and hover performance of the basic OH-58A helicopter remained unchanged. (Author).
Download or read book Operator's Manual written by and published by . This book was released on 1989 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Yaw Axis Stability Augmentation System Flight Test Report by : Harvey Ogren
Download or read book Yaw Axis Stability Augmentation System Flight Test Report written by Harvey Ogren and published by . This book was released on 1974 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: The report describes the design and flight tests of a hydrofluidic yaw stability augmentation system (SAS) for an OH-58A helicopter. The design objective was to improve stability characteristics in yaw for all flight conditions from hover to 120 kn. The yaw SAS, which initially featured only high-passed yaw rate feedback, was installed in an OH-58A helicopter and flight tested in 1972. Performance at forward flight speeds was satisfactory; but at hover, yaw rates were excessive. The system was then modified to add a straight-through yaw rate feedback term. Flight tests of this configuration were conducted from October-December 1973. Results were satisfactory. (Author).
Book Synopsis U.S. Army H-25 Helicopter Drop Test, 22 October 1960 by : James William Turnbow
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:
Book Synopsis Evaluation of an OH-58A Helicopter with an Allison 250-C20B Engine by : Tom P. Benson
Download or read book Evaluation of an OH-58A Helicopter with an Allison 250-C20B Engine written by Tom P. Benson and published by . This book was released on 1975 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Introduction to autogyros, helicopters, and other V/STOL aircraft by : Franklin D. Harris
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:
Book Synopsis Engine and Transmission Oils, Fuels, and Additives for Army Aircraft by :
Download or read book Engine and Transmission Oils, Fuels, and Additives for Army Aircraft written by and published by . This book was released on 1992 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Rotary-Wing Aerodynamics by : W. Z. Stepniewski
Download or read book Rotary-Wing Aerodynamics written by W. Z. Stepniewski and published by Courier Corporation. This book was released on 2013-04-22 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: DIVClear, concise text covers aerodynamic phenomena of the rotor and offers guidelines for helicopter performance evaluation. Originally prepared for NASA. Prefaces. New Indexes. 10 black-and-white photos. 537 figures. /div
