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At least 73 records · Page 4

Aircraft flight flutter testing at the NASA Ames-Dryden Flight Research Facility

Many parameter identification techniques have been used at the NASA Ames Research Center, Dryden Flight Research Facility at Edwards Air Force Base to determine the aeroelastic stability of new and modified research vehicles in flight. This paper presents a summary of each technique used with emphasis on fast Fourier transform methods. Experiences gained from application of these techniques to various flight test programs are discussed. Also presented are data-smoothing techniques used for test data distorted by noise. Data are presented for various aircraft to demonstrate the accuracy of each parameter identification technique discussed.

Kehoe, Michael W.↗

An Indispensable Ingredient: Flight Research and Aircraft Design

Flight research-the art of flying actual vehicles in the atmosphere in order to collect data about their behavior-has played a historic and decisive role in the design of aircraft. Naturally, wind tunnel experiments, computational fluid dynamics, and mathematical analyses all informed the judgments of the individuals who conceived of new aircraft. But flight research has offered moments of realization found in no other method. Engineer Dale Reed and research pilot Milt Thompson experienced one such epiphany on March 1, 1963, at the National Aeronautics and Space Administration s Dryden Flight Research Center in Edwards, California. On that date, Thompson sat in the cockpit of a small, simple, gumdrop-shaped aircraft known as the M2-F1, lashed by a long towline to a late-model Pontiac Catalina. As the Pontiac raced across Rogers Dry Lake, it eventually gained enough speed to make the M2-F1 airborne. Thompson braced himself for the world s first flight in a vehicle of its kind, called a lifting body because of its high lift-to-drag ratio. Reed later recounted what he saw:

Gorn, Michael H.↗

Flight simulation software at NASA Dryden Flight Research Center

The NASA Dryden Flight Research Center has developed a versatile simulation software package that is applicable to a broad range of fixed-wing aircraft. This package has evolved in support of a variety of flight research programs. The structure is designed to be flexible enough for use in batch-mode, real-time pilot-in-the-loop, and flight hardware-in-the-loop simulation. Current simulations operate on UNIX-based platforms and are coded with a FORTRAN shell and C support routines. This paper discusses the features of the simulation software design and some basic model development techniques. The key capabilities that have been included in the simulation are described. The NASA Dryden simulation software is in use at other NASA centers, within industry, and at several universities. The straightforward but flexible design of this well-validated package makes it especially useful in an engineering environment.

Norlin, Ken A.↗

NASA Flight Research Center scale F-15 remotely piloted research vehicle program

The NASA Flight Research Center undertook a remotely piloted research vehicle (RPRV) program with a 3/8-scale model of an F-15 aircraft to determine the usefulness of the RPRV testing technique in high-risk flight testing such as spin testing. The results of the first flights of the program are presented. The program has shown that the RPRV technique, including the use of a digital control system, is a viable method for obtaining flight research data. Also presented are some negative aspects that have been learned about the RPRV technique in terms of model size, command frequency, and launch technique.

Layton, G. P.↗

Flight Research Using F100 Engine P680063 in the NASA F-15 Airplane

The value of flight research in developing and evaluating gas turbine engines is high. NASA Dryden Flight Research Center has been conducting flight research on propulsion systems for many years. The F100 engine has been tested in the NASA F-15 research airplane in the last three decades. One engine in particular, S/N P680063, has been used for the entire program and has been flown in many pioneering propulsion flight research activities. Included are detailed flight-to-ground facility tests; tests of the first production digital engine control system, the first active stall margin control system, the first performance-seeking control system; and the first use of computer-controlled engine thrust for emergency flight control. The flight research has been supplemented with altitude facility tests at key times. This paper presents a review of the tests of engine P680063, the F-15 airplanes in which it flew, and the role of the flight test in maturing propulsion technology.

Burcham, Frank W., Jr.↗

UAS Related Activities at NASA's Dryden Flight Research Center

NASA's Dryden Flight Research Center is completing its refurbishment and initial flights of one the pre-production Global Hawk aircraft it received from the U.S. Air Force. NASA Dryden has an agreement with the Global Hawk s manufacturer, Northrop Grumman, to partner in the refurbishment and flight operations of the vehicles. The National Oceanic and Atmospheric Administration (NOAA) has also partnered on the project and is assisting NASA with project management and pilot responsibilities for the aircraft. NASA and NOAA will be using the Global Hawks to conduct earth science research. The earth science community is increasing utilizing UAS of all sizes and capabilities to collect important data on a variety of issues including important global climate change issues. To pursue the data collection needs of the science community there is a growing demand for international collaboration with respect to operating UAS in global airspace. Operations of NASA s Ikhana aircraft continued this past year. The Ikhana is a modified Predator B UAS. A UAS dedicated to research at NASA Dryden is the X-48B blended wing body research aircraft. Flight tests with the 500- pound, remotely piloted test vehicle are now in a block 4 phase involving parameter identification and maneuvers to research the limits of the engine in stall situations. NASA s participation in the blended wing body research effort is focused on fundamental, advanced flight dynamics and structural design concepts within the Subsonic Fixed Wing project, part of the Fundamental Aeronautics program managed through NASA s Aeronautics Research Mission Directorate. Potential benefits of the aircraft include increased volume for carrying capacity, efficient aerodynamics for reduced fuel burn and possibly significant reductions in noise due to propulsion integration options. NASA Dryden continues to support the UAS industry by facilitating access to three specially designated test areas on Edwards Air Force Base for the development of small UAS.

Bauer, Jeffrey E.↗

Fairing Well: Aerodynamic Truck Research at NASA Dryden Flight Research Center

In 1973 engineers at Dryden began investigating ways to reduce aerodynamic drag on land vehicles. They began with a delivery van whose shape they changed dramatically, finally reducing its aerodynamic drag by more than 5 percent. They then turned their attention to tracator-trailers, modifying a cab-over and reducing its aerodynamic drag by nearly 25 percent. Further research identified additional areas worth attention, but in the intervening decades few of those changes have appeared.

Gelzer, Christian↗

Flights of Discovery: 50 Years at the NASA Dryden Flight Research Center

As part of the NASA History Series, this report (NASA SP-4309) describes fifty years of aeronautical research at the NASA Dryden Flight Research Center. Starting with early efforts to exceed the speed of sound with the X-1 aircraft, and continuing through to the X-31 research aircraft, the report covers the flight activities of all of the major research aircraft and lifting bodies studied by NASA. Chapter One, 'A Place for Discovery', describes the facility itself and the surrounding Mojave Desert. Chapter Two, 'The Right Stuff', is about the people involved in the flight research programs. Chapter Three, 'Higher, Faster' summarizes the early years of transonic flight testing and the development of several lifting bodies. Chapter Four, 'Improving Efficiency, Maneuverability & Systems', outlines the development of aeronautical developments such as the supercritical wing, the mission adaptive wing, and various techniques for improving maneuverability fo winged aircraft. Chapter 5, 'Supporting National Efforts', shows how the research activities carried out at Dryden fit into NASA's programs across the country in supporting the space program, in safety and in problem solving related to aircraft design and aviation safety in general. Chapter Six, ' Future Directions' looks to future research building on the fifty year history of aeronautical research at the Dryden Flight Research Center. A glossary of acronyms and an appendix covering concepts and innovations are included. The report also contains many photographs providing a graphical perspective to the historical record.

Lane E Wallace↗

Development of a low-aspect ratio fin for flight research experiments

A second-generation flight test fixture, developed at NASA Dryden Flight Research Center, offers a generic testbed for aerodynamic and fluid mechanics research. The new fixture, a low-aspect ratio vertical fin shape mounted on the centerline of an F-15B aircraft lower fuselage, is designed for flight research at Mach numbers up to 2.0. The new fixture is a composite structure with a modular configuration and removable components for functional flexibility. This report describes the multidisciplinary design and analysis approach used to develop the fixture. The approach integrates conservative assumptions with simple analysis techniques to minimize the time and cost associated with its development. Presented are the principal disciplines required for this effort, which include aerodynamics, structures, stability, and operational considerations. In addition, preliminary results from the first phase of flight testing are presented. Acceptable directional stability and flow quality are documented and show agreement with predictions. Future envelope expansion activities will minimize current limitations so that the fixture can be used for a wide variety of high-speed aerodynamic and fluid mechanics research experiments.

Richwine, David M.↗

Summary of results of NASA F-15 flight research program

NASA conducted a multidisciplinary flight research program on the F-15 airplane. The program began in 1976 when two preproduction airplanes were obtained from the U.S. Air Force. Major projects involved stability and control, handling qualities, propulsion, aerodynamics, propulsion controls, and integrated propulsion-flight controls. Several government agencies and aerospace contractors were involved. In excess of 330 flights were flown, and over 85 papers and reports were published. This document describes the overall program, the projects, and the key results. The F-15 was demonstrated to be an excellent flight research vehicle, producing high-quality results.

Burcham, F. W., Jr.↗

Summary of results of NASA F-15 flight research program

NASA conducted a multidisciplinary flight research program on the F-15 airplane. The program began in 1976 when two preproduction airplanes were obtained from the U.S. Air Force. Major projects involved stability and control, handling qualities, propulsion, aerodynamics, propulsion controls, and integrated propulsion-flight controls. Several government agencies and aerospace contractors were involved. In excess of 330 flights were flown, and over 85 papers and reports were published. This document describes the overall program, the projects, and the key results. The F-15 was demonstrated to be an excellent flight research vehicle, producing high-quality results.

Burcham, F. W., Jr.↗

Aircraft ground vibration testing at the NASA Dryden Flight Research Facility, 1993

The NASA Dryden Flight Research Facility performs ground vibration testing to assess the structural characteristics of new and modified research vehicles. This paper updates the research activities, techniques used, and experiences in applying this technology to aircraft since 1987. Test equipment, data analysis methods, and test procedures used for typical test programs are discussed. The data presented illustrate the use of modal test and analysis in flight research programs for a variety of aircraft. This includes a technique to acquire control surface free-play measurements on the X-31 airplane more efficiently, and to assess the effects of structural modifications on the modal characteristics of an F-18 aircraft. In addition, the status and results from current research activities are presented. These data show the effectiveness of the discrete modal filter as a preprocessor to uncouple response measurements into simple single-degree-of-freedom responses, a database for the comparison of different excitation methods on a JetStar airplane, and the effect of heating on modal frequency and damping.

Kehoe, Michael W.↗

Quiet Short-Haul Research Aircraft - A summary of flight research since 1981

The Quiet Short-Haul Research Aircraft (QSRA), designed for flight investigation into powered-lift terminal area operations, first flew in 1978 and has flown 600 hours since. This report summarizes QSRA research since 1981. Numerous aerodynamic flight experiments have been conducted including research with an advanced concept stability and control augmentation and pilot display system for category III instrument landings. An electromechanical actuator system was flown to assess performance and reliability. A second ground-based test was conducted to further evaluate circulation-control-wing/upper-surface-blowing performance. QSRA technology has been transferred through reports, guest pilot evaluations and airshow participation. QSRA future research thoughts and an extensive report bibliography are also presented.

Riddle, Dennis W.↗

On the frontier: Flight research at Dryden 1946-1981

The history of flight research at the NASA Hugh L. Dryden Flight Research Center is recounted. The period of emerging supersonic flight technology (1944 to 1959) is reviewed along with the era of flight outside the Earth's atmosphere (1959 to 1981). Specific projects such as the X-15, Gemini, Apollo, and the space shuttle are addressed. The flight chronologies of various aircraft and spacecraft are given.

Hallion, R. P.↗

The NASA Urban Air Mobility Testbed Flight Research Aircraft

The National Aeronautics and Space Administration (NASA) is leading government, industry and academic research effort known as Urban Air Mobility (UAM). The UAM activity goal is to develop the technology needed to make possible an urban air transportation system that makes use of human-crewed and crewless vehicles using automation, artificial intelligence and other technologies to safely and efficiently air transport people and goods within an urban environment. The NASA Langley Research Center (LaRC) created a UAM Flight Research Testbed Aircraft from a Cessna LC40 general aviation aircraft. The testbed has updated digital avionics and research systems needed to conduct flight research. The aircraft has two separate autopilots; a standard Federal Aviation Ad-ministration (FAA) certified system, and a modified research autopilot. The research autopilot has modifications that allow increased authority and enhancements to allow more automation and artificial intelligence controls. A network of three research computers hosts software to research several activities including automated air traffic sense and avoid, ground collision avoidance and obstacle avoidance. These UAM research activities involve automation and artificial intelligence technologies developed at three NASA centers. The NASA Langley, NASA Armstrong, and NASA Ames Research Centers are working together to develop and test these UAM technologies. This paper provides details of the systems, capabilities and research projects of the UAM Testbed Research Aircraft.

Howell, Charles T.↗

Early Years of NASA Ames Flight Research

A review of select flight research programs illustrate the challenges of conducting flight tests in the early years of flight testing. The results show significant contributions to advance progress in aeronautics.

Anderson, Seth B.↗