Download or read book On Subscale Flight Testing written by Alejandro Sobron and published by Linköping University Electronic Press. This book was released on 2018-11-05 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: Downscaled physical models, also referred to as subscale models, have played an essential role in the investigation of the complex physics of flight until the recent disruption of numerical simulation. Despite the fact that improvements in computational methods are slowly pushing experimental techniques towards a secondary role as verification or calibration tools, real-world testing of physical prototypes still provides an unmatched confidence. Physical models are very effective at revealing issues that are sometimes not correctly identified in the virtual domain, and hence can be a valuable complement to other design tools. But traditional wind-tunnel testing cannot always meet all of the requirements of modern aeronautical research and development. It is nowadays too expensive to use these scarce facilities to explore different design iterations during the initial stages of aircraft development, or to experiment with new and immature technologies. Testing of free-flight subscale models, referred to as Subscale Flight Testing (SFT), could offer an affordable and low-risk alternative for complementing conventional techniques with both qualitative and quantitative information. The miniaturisation of mechatronic systems, the advances in rapid-prototyping techniques and power storage, as well as new manufacturing methods, currently enable the development of sophisticated test objects at scales that were impractical some decades ago. Moreover, the recent boom in the commercial drone industry has driven a quick development of specialised electronics and sensors, which offer nowadays surprising capabilities at competitive prices. These recent technological disruptions have significantly altered the cost-benefit function of SFT and it is necessary to re-evaluate its potential in the contemporary aircraft development context. This thesis aims to increase the comprehension and knowledge of the SFT method in order to define a practical framework for its use in aircraft design; focusing on low-cost, short-time solutions that don’t require more than a small organization and few resources. This objective is approached from a theoretical point of view by means of an analysis of the physical and practical limitations of the scaling laws; and from an empirical point of view by means of field experiments aimed at identifying practical needs for equipment, methods, and tools. A low-cost data acquisition system is developed and tested; a novel method for semi-automated flight testing in small airspaces is proposed; a set of tools for analysis and visualisation of flight data is presented; and it is also demonstrated that it is possible to explore and demonstrate new technology using SFT with a very limited amount of economic and human resources. All these, together with a theoretical review and contextualisation, contribute to increasing the comprehension and knowledge of the SFT method in general, and its potential applications in aircraft conceptual design in particular.
Download or read book Flight Test System Identification written by Roger Larsson and published by Linköping University Electronic Press. This book was released on 2019-05-15 with total page 326 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the demand for more advanced fighter aircraft, relying on unstable flight mechanical characteristics to gain flight performance, more focus has been put on model-based system engineering to help with the design work. The flight control system design is one important part that relies on this modeling. Therefore, it has become more important to develop flight mechanical models that are highly accurate in the whole flight envelope. For today’s modern fighter aircraft, the basic flight mechanical characteristics change between linear and nonlinear as well as stable and unstable as an effect of the desired capability of advanced maneuvering at subsonic, transonic and supersonic speeds. This thesis combines the subject of system identification, which is the art of building mathematical models of dynamical systems based on measurements, with aeronautical engineering in order to find methods for identifying flight mechanical characteristics. Here, some challenging aeronautical identification problems, estimating model parameters from flight-testing, are treated. Two aspects are considered. The first is online identification during flight-testing with the intent to aid the engineers in the analysis process when looking at the flight mechanical characteristics. This will also ensure that enough information is available in the resulting test data for post-flight analysis. Here, a frequency domain method is used. An existing method has been developed further by including an Instrumental Variable approach to take care of noisy data including atmospheric turbulence and by a sensor-fusion step to handle varying excitation during an experiment. The method treats linear systems that can be both stable and unstable working under feedback control. An experiment has been performed on a radio-controlled demonstrator aircraft. For this, multisine input signals have been designed and the results show that it is possible to perform more time-efficient flight-testing compared with standard input signals. The other aspect is post-flight identification of nonlinear characteristics. Here the properties of a parameterized observer approach, using a prediction-error method, are investigated. This approach is compared with four other methods for some test cases. It is shown that this parameterized observer approach is the most robust one with respect to noise disturbances and initial offsets. Another attractive property is that no user parameters have to be tuned by the engineers in order to get the best performance. All methods in this thesis have been validated on simulated data where the system is known, and have also been tested on real flight test data. Both of the investigated approaches show promising results.
Download or read book Sweeping Forward written by and published by . This book was released on 2013 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The X-29 was an unusual aircraft with a truly unique silhouette. It combined many features that challenged the technologies of its day and represented special problems for the developers and the team of testers responsible for documenting its features and design goals. This book is a look at the "big picture" of what this team accomplished in a relatively fast-paced test program involving the truly unique X-29.
Download or read book Evaluation of the National Aerospace Initiative written by National Research Council and published by National Academies Press. This book was released on 2004-06-16 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: The National Aerospace Initiative (NAI) was conceived as a joint effort between the Department of Defense (DOD) and the National Aeronautics and Space Administration (NASA) to sustain the aerospace leadership of the United States through the acceleration of selected aerospace technologies: hypersonic flight, access to space, and space technologies. The Air Force became concerned about the NAI's possible consequences on Air Force programs and budget if NAI program decisions differed from Air Force priorities. To examine this issue, it asked the NRC for an independent review of the NAI. This report presents the results of that assessment. It focuses on three questions asked by the Air Force: is NAI technically feasible in the time frame laid out; is it financially feasible over that period; and is it operationally relevant.
Download or read book Flying beyond the stall written by Douglas A. Joyce and published by . This book was released on 2014 with total page 409 pages. Available in PDF, EPUB and Kindle. Book excerpt: The X-31 Enhanced Fighter Maneuverability Demonstrator was unique among experimental aircraft. A joint effort of the United States and Germany, the X-31 was the only X-plane to be designed, manufactured, and flight tested as an international collaboration. It was also the only X-plane to support two separate test programs conducted years apart, one administered largely by NASA and the other by the U.S. Navy, as well as the first X-plane ever to perform at the Paris Air Show. Flying Beyond the Stall begins by describing the government agencies and private-sector industries involved in the X-31 program, the genesis of the supermaneuverability concept and its initial design breakthroughs, design and fabrication of two test airframes, preparation for the X-31's first flight, and the first flights of Ship #1 and Ship #2. Subsequent chapters discuss envelope expansion, handling qualities (especially at high angles of attack), and flight with vectored thrust. The book then turns to the program's move to NASA's Dryden Flight Research Center and actual flight test data. Additional tasking, such as helmet-mounted display evaluations, handling quality studies, aerodynamic parameter estimation, and a "tailless" study are also discussed.The book describes how, in the aftermath of a disastrous accident with Ship #1 in 1995, Ship #2 was prepared for its outstanding participation in the Paris Air Show. The aircraft was then shipped back to Edwards AFB and put into storage until the late 1990s, when it was refurbished for participation in the U. S. Navy's VECTOR program. The book ends with a comprehensive discussion of lessons learned and includes an Appendix containing detailed information.
Download or read book Flight Testing of Airbreathing Hypersonic Vehicles written by John W. Hicks and published by . This book was released on 1993 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reusable Launch Vehicle written by Committee on Reusable Launch Vehicle Technology and Test Program and published by National Academies Press. This book was released on 1996-01-22 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: The key to opening the use of space to private enterprise and to broader public uses lies in reducing the cost of the transportation to space. More routine, affordable access to space will entail aircraft-like quick turnaround and reliable operations. Currently, the space Shuttle is the only reusable launch vehicle, and even parts of it are expendable while other parts require frequent and extensive refurbishment. NASA's highest priority new activity, the Reusable Launch Vehicle program, is directed toward developing technologies to enable a new generation of space launchers, perhaps but not necessarily with single stage to orbit capability. This book assesses whether the technology development, test and analysis programs in propulsion and materials-related technologies are properly constituted to provide the information required to support a December 1996 decision to build the X-33, a technology demonstrator vehicle; and suggest, as appropriate, necessary changes in these programs to ensure that they will support vehicle feasibility goals.
Download or read book Aeronautics and Space Report of the President Activities written by United States. President and published by . This book was released on 1989 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeronautics and Space Report of the President written by United States. President and published by . This book was released on 1990 with total page 602 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Abstract Bulletin written by Defense Documentation Center (U.S.) and published by . This book was released on 1967 with total page 784 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advances in Aircraft Brakes and Tires written by Robert Kyle Schmidt and published by SAE International. This book was released on 2015-08-24 with total page 126 pages. Available in PDF, EPUB and Kindle. Book excerpt: An aircraft’s interface with the ground—through its wheels, tires, and brakes—is critical to ensure safe and reliable operation, demanding constant technology development. Significant advancements have occurred with almost all civil airliners entering service with radial tires, and with the Boeing 787 having entered service in 2011 with electrically actuated carbon-carbon brakes. This book is divided into three sections: tires, control systems, and brakes, presenting a selection of the most relevant papers published by SAE International on these matters in the past fifteen years. They have been chosen to provide significant interest to those engineers working in the landing gear field. With almost all current large civil aircraft (and many smaller aircraft) opting exclusively for carbon-carbon brakes, a number of papers addressing the challenges of this technology are included. Papers touching on tire behavior and papers discussing brake control strategies are provided. For those looking for more information on aircraft landing gears, brakes, and tires, the SAE A-5 committee (the Aerospace Landing Gear Systems Committee), which meets twice a year, serves as a useful forum for discussion on landing gear issues and development. A current listing of documents produced and maintained by the A-5 committee is included in the appendix.
Download or read book Department of Defense Appropriations for Fiscal Year 1969 written by United States. Congress. Senate. Committee on Appropriations. Subcommittee on Department of Defense and published by . This book was released on 1968 with total page 540 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Department of Defense Appropriations for Fiscal Year 1969 Hearings Before 90 2 written by United States. Congress. Senate. Appropriations Committee and published by . This book was released on 1968 with total page 2494 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Department of the Air Force written by United States. Congress. Senate. Committee on Appropriations. Subcommittee on Department of Defense and published by . This book was released on 1968 with total page 554 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hearings Reports and Prints of the Senate Committee on Appropriations written by United States. Congress. Senate. Committee on Appropriations and published by . This book was released on 1968 with total page 1106 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book National Aero space Plane written by United States. General Accounting Office and published by . This book was released on 1992 with total page 60 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Department of Defense Appropriations for 1969 written by United States. Congress. House. Committee on Appropriations and published by . This book was released on 1968 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt:
