Download or read book An Analytic Investigation of Accuracy Requirements for Onboard Instrumentation and Film Data for Dynamically Scaled Wind Tunnel Drop Models written by K. S. Keen and published by . This book was released on 1997 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytic study was conducted to evaluate anticipated ranges and required accuracies for onboard linear acceleration and angular rate (or acceleration) measurement equipment to be mounted within dynamically scaled wind tunnel drop models. Generic simulations of the separation motion of a tumbling fuel tank both at full scale and at 1/15th wind tunnel model scale were generated using an analytic trajectory simulation program coupled with a prescribed aerodynamic database. The simulations provide a basis for sizing the required instrumentation for proof of concept demonstrations of telemetry techniques in the wind tunnel. The simulations were also used as test cases to demonstrate extraction of aerodynamic information from drop data positions and orientations as read from film records via an inverse solution of the store equations of motion. The studies also aid identification and evaluation of inaccuracies associated with the basic dynamic scaling laws and standard film based data reduction techniques.

Download or read book An Analytic Investigation of Accuracy Requirements for Onboard Instrumentation and Film Data for Dynamically Scaled Wind Tunnel Drop Models written by and published by . This book was released on 1997 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt: An analytic study was conducted to evaluate anticipated ranges and required accuracies for onboard linear acceleration and angular rate (or acceleration) measurement equipment to be mounted within dynamically scaled wind tunnel drop models. Generic simulations of the separation motion of a tumbling fuel tank both at full scale and at 1/15th wind tunnel model scale were generated using an analytic trajectory simulation program coupled with a prescribed aerodynamic database. The simulations provide a basis for sizing the required instrumentation for proof of concept demonstrations of telemetry techniques in the wind tunnel. The simulations were also used as test cases to demonstrate extraction of aerodynamic information from drop data positions and orientations as read from film records via an inverse solution of the store equations of motion. The studies also aid identification and evaluation of inaccuracies associated with the basic dynamic scaling laws and standard film based data reduction techniques.

Download or read book The Development and Evaluation of the CAL Air Force Dynamic Wind tunnel Testing System written by Irving C. Statler and published by . This book was released on 1967 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Cornell Aeronautical Laboratory (CAL) system provides a unique mounting through which a model can be forced precisely in any desired planar sinusoidal motion. The versatility and overall accuracy of the CAL/Air Force dynamic testing system was demonstrated during a series of wind-tunnel tests. These tests permitted, for the first time, a measurement of the separate components of the rotary damping moment. The moment due to rate of change of angle of attack was measured by oscillating the model in pure plunging motion. The moment due to pitch rate was measured during pitching motion. The sum of these is compared with the total rotary damping moment as measured in rotation. Comparisons of data taken at two frequencies and four Mach numbers indicate that the components are accurate to within plus or minus ten percent of the total rotary damping moment. The results are compared with theory, flight test data, and other wind-tunnel measurements on the same and similar models. Future applications of this equipment are reviewed, particularly with regard to its use as a research tool to support basic investigations for the development of theoretical or semiempirical methods for predicting dynamic stability characteristics of aircraft at transonic speeds. (Author).

Download or read book Government Reports Announcements Index written by and published by . This book was released on 1995 with total page 782 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1986 with total page 1162 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Modal Correction Method for Dynamically Induced Errors in Wind Tunnel Model Attitude Measurements written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-12-30 with total page 28 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper describes a method for correcting the dynamically induced bias errors in wind tunnel model attitude measurements using measured modal properties of the model system. At NASA Langley Research Center, the predominant instrumentation used to measure model attitude is a servo-accelerometer device that senses the model attitude with respect to the local vertical. Under smooth wind tunnel operating conditions, this inertial device can measure the model attitude with an accuracy of 0.01 degree. During wind tunnel tests when the model is responding at high dynamic amplitudes, the inertial device also senses the centrifugal acceleration associated with model vibration. This centrifugal acceleration results in a bias error in the model attitude measurement. A study of the response of a cantilevered model system to a simulated dynamic environment shows significant bias error in the model attitude measurement can occur and is vibration mode and amplitude dependent. For each vibration mode contributing to the bias error, the error is estimated from the measured modal properties and tangential accelerations at the model attitude device. Linear superposition is used to combine the bias estimates for individual modes to determine the overall bias error as a function of time. The modal correction model predicts the bias error to a high degree of accuracy for the vibration modes characterized in the simulated dynamic environment. Buehrle, R. D. and Young, C. P., Jr. Langley Research Center NASA-TM-111560, NAS 1.15:111560 ...

Download or read book Dependence of Dynamic Modeling Accuracy on Sensor Measurements Mass Properties and Aircraft Geometry written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-05-22 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NASA Generic Transport Model (GTM) nonlinear simulation was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of identified parameters in mathematical models describing the flight dynamics and determined from flight data. Measurements from a typical flight condition and system identification maneuver were systematically and progressively deteriorated by introducing noise, resolution errors, and bias errors. The data were then used to estimate nondimensional stability and control derivatives within a Monte Carlo simulation. Based on these results, recommendations are provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using additional flight conditions and parameter estimation methods, as well as a nonlinear flight simulation of the General Dynamics F-16 aircraft, were compared with these recommendations Grauer, Jared A. and Morelli, Eugene A. Langley Research Center DYNAMIC MODELS; MATHEMATICAL MODELS; FLIGHT SIMULATION; ERRORS; AIRCRAFT INSTRUMENTS; MEASURING INSTRUMENTS; SYSTEM IDENTIFICATION; COMPUTER AIDED DESIGN; MONTE CARLO METHOD; AIRCRAFT STABILITY

Download or read book Dynamic Response Tests of Inertial and Optical Wind Tunnel Model Attitude Measurement Devices written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-02 with total page 46 pages. Available in PDF, EPUB and Kindle. Book excerpt: Results are presented for an experimental study of the response of inertial and optical wind-tunnel model attitude measurement systems in a wind-off simulated dynamic environment. This study is part of an ongoing activity at the NASA Langley Research Center to develop high accuracy, advanced model attitude measurement systems that can be used in a dynamic wind-tunnel environment. This activity was prompted by the inertial model attitude sensor response observed during high levels of model vibration which results in a model attitude measurement bias error. Significant bias errors in model attitude measurement were found for the measurement using the inertial device during wind-off dynamic testing of a model system. The amount of bias present during wind-tunnel tests will depend on the amplitudes of the model dynamic response and the modal characteristics of the model system. Correction models are presented that predict the vibration-induced bias errors to a high degree of accuracy for the vibration modes characterized in the simulated dynamic environment. The optical system results were uncorrupted by model vibration in the laboratory setup. Buehrle, R. D. and Young, C. P., Jr. and Burner, A. W. and Tripp, J. S. and Tcheng, P. and Finley, T. D. and Popernack, T. G., Jr. Langley Research Center RTOP 505-59-54-01...

Download or read book Instrument Error Analysis as it Applies to Wind tunnel Testing written by Emanuel Rind and published by . This book was released on 1979 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Popular Science written by and published by . This book was released on 2007-08 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: Popular Science gives our readers the information and tools to improve their technology and their world. The core belief that Popular Science and our readers share: The future is going to be better, and science and technology are the driving forces that will help make it better.

Download or read book Aeronautical Engineering written by and published by . This book was released on 1991 with total page 168 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 NASA SP written by and published by . This book was released on 1991 with total page 668 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Advanced Aerodynamic Measurement Technology written by North Atlantic Treaty Organization. Advisory Group for Aerospace Research and Development. Fluid Dynamics Panel. Symposium and published by . This book was released on 1998 with total page 444 pages. Available in PDF, EPUB and Kindle. Book excerpt: The demands for higher performance for modern aircraft have led the wind tunnel community, which is an integral link in the design process, to develop more refined and cost effective measuring techniques. These technologies have gradually matured from laboratory novelties into instruments regularly used in aerodynamic testing. The development of these modern measurement techniques has greatly extended the capability and accuracy of the classical methods for measurement techniques and provided better insight into flow physics. This Symposium provided a forum for active researchers to address the state-of-the-art, to exchange experiences and ideas, and for the practitioners to obtain an overview of the technology and learn how to appy it.

Download or read book Integrated Experimental and Numerical Research on the Aerodynamics of Unsteady Moving Aircraft written by and published by . This book was released on 2007 with total page 51 pages. Available in PDF, EPUB and Kindle. Book excerpt: For the experimental determination of the dynamic wind tunnel data a new combined motion test capability was developed at the German-Dutch Wind Tunnels DNW for their 3m Low Speed Wind Tunnel NWB in Braunschweig, Germany, using a unique six degree-of-freedom test rig called?Model Positioning Mechanism? (MPM) as an improved successor to the older systems. With that cutting-edge device several transport aircraft configurations including a blended wing body configuration were tested in different modes of oscillatory motions roll, pitch and yaw as well as delta wing geometries like X-31 equipped with remote controlled rudders and flaps to be able to simulate realistic flight maneuvers, e.g. a dutch-roll. This paper describes the motivation behind these tests and the test setup and in addition gives a short introduction into time accurate maneuver testing capabilities incorporating models with remote controlled control surfaces. Furthermore, the adaptation of numerical methods for the prediction of dynamic derivatives is described and some examples with the DLR-F12 configuration will be given. The calculations are based on RANS-solution using the finite volume parallel solution algorithm with an unstructured discretization concept (DLR TAU-code).

Download or read book The Development and Evaluation of the CAL Air Force Dynamic Wind tunnel Testing System written by Irving C. Statler and published by . This book was released on 1967 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The F-104 model was designed and fabricated by the Air Force Flight Dynamics Laboratory and incorporated an unusual force and motion sensing system utilizing an internal dummy model with duplicate mass, inertia, and c.g. location. Longitudinal dynamic tests were performed with this model up through the transonic speed range. The results are evaluated with respect to the operation of the dynamic testing system and to the performance of the dummy model for measuring motion and canceling inertial loads.

Download or read book A Common Geometric Data Base Approach for Computer Aided Manufacturing of Wind Tunnel Models and Theoretical Aerodynamic Analysis written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-21 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: A more automated process to produce wind tunnel models using existing facilities is discussed. A process was sought to more rapidly determine the aerodynamic characteristics of advanced aircraft configurations. Such aerodynamic characteristics are determined from theoretical analyses and wind tunnel tests of the configurations. Computers are used to perform the theoretical analyses, and a computer aided manufacturing system is used to fabricate the wind tunnel models. In the past a separate set of input data describing the aircraft geometry had to be generated for each process. This process establishes a common data base by enabling the computer aided manufacturing system to use, via a software interface, the geometric input data generated for the theoretical analysis. Thus, only one set of geometric data needs to be generated. Tests reveal that the process can reduce by several weeks the time needed to produce a wind tunnel model component. In addition, this process increases the similarity of the wind tunnel model to the mathematical model used by the theoretical aerodynamic analysis programs. Specifically, the wind tunnel model can be machined to within 0.008 in. of the original mathematical model. However, the software interface is highly complex and cumbersome to operate, making it unsuitable for routine use. The procurement of an independent computer aided design/computer aided manufacturing system with the capability to support both the theoretical analysis and the manufacturing tasks was recommended. See, M. J. and Cozzolongo, J. V. Ames Research Center NASA-TP-2151, A-9169, NAS 1.60:2151 RTOP 505-31-21

Download or read book Analysis of Flight Data from a High Incidence Research Model by System Identification Methods written by National Aeronautics and Space Adm Nasa and published by Independently Published. This book was released on 2018-10-26 with total page 58 pages. Available in PDF, EPUB and Kindle. Book excerpt: Data partitioning and modified stepwise regression were applied to recorded flight data from a Royal Aerospace Establishment high incidence research model. An aerodynamic model structure and corresponding stability and control derivatives were determined for angles of attack between 18 and 30 deg. Several nonlinearities in angles of attack and sideslip as well as a unique roll-dominated set of lateral modes were found. All flight estimated values were compared to available wind tunnel measurements. Batterson, James G. and Klein, Vladislav Langley Research Center...