45th AIAA Aerospace Sciences Meeting and Exhibit, Jan 8, 2007
In order to determine the feasibility of a powered lift civilian transport aircraft that will emp... more In order to determine the feasibility of a powered lift civilian transport aircraft that will employ alternate approach and departure trajectories, NASA commissioned CENTRA Technology, Inc. to develop the Conceptual Aircraft Trajectory Simulator (CATS). This simulation processes the proposed trajectory by analyzing the input position points (latitude, longitude, and altitude) as well as the aircraft velocity at each point. CATS simulates the required angle of attack and thrust levels at each time step along with providing other parameters such as: component velocities, heading, flight path angle, bank angle, lift and drag factors. By using actual flight data acquired during the September 2005 C-17 Noise Mitigation Flight Test, the analysis verifies that the results from CATS generated simulations matched those of an actual flight.
In 2014, the Vertical Flight Society (VFS) organized a series of workshops on Transformative Vert... more In 2014, the Vertical Flight Society (VFS) organized a series of workshops on Transformative Vertical Flight (TVF) in collaboration with NASA, the American Institute of Aeronautics and Astronautics (AIAA) and the Society of Automotive Engineers (SAE). The intent was to build a community of aerospace professionals that included technical, regulatory, and business elements, organized into several working groups, to explore potential future air transportation systems with innovative vertical takeoff and landing (VTOL) aircraft. Between 2014 and 2020 the annual TVF workshops focused on systems that embody combinations of on-demand, electric and hybrid-electric propulsion and vertiport-capable configurations and designs while identifying areas of potential interdisciplinary collaborations and solicited expert opinions from the participants on the work and timeframes required to transform air transportation. The workshops and working groups served as the basis for developing an advocacy roadmap and white paper on TVF transportation systems, technology, and markets. Acknowledgments Dedication This white paper is dedicated to Mr. Michael Dudley, whose passion, enthusiasm, and motivation in the Transformative Vertical Flight Working Groups inspired us to pursue the revolution of eVTOL aircraft NASA TVF WG Sponsor Vertical Flight Society
The focus of the current research is to numerically predict an infrared image of a jet engine exh... more The focus of the current research is to numerically predict an infrared image of a jet engine exhaust plume, given field variables such as temperature, pressure, and exhaust plume constituents as a function of spatial position within the plume, and to compare this predicted image ...
The focus of this research is to numerically predict an infrared image of a jet engine exhaust pl... more The focus of this research is to numerically predict an infrared image of a jet engine exhaust plume, given field variables such as temperature, pressure, and exhaust plume constituents as a function of spatial position within the plume, and to compare this predicted image ...
Hover and ground-effect tests were conducted with the Lockheed-Martin Large Scale Powered Model (... more Hover and ground-effect tests were conducted with the Lockheed-Martin Large Scale Powered Model (LSPM) during June-November 1995 at the NASA Ames Research Center's Outdoor Aerodynamics Research Facility (OARF). This was done in support of the Joint Strike Fighter (JSF) Program being lead by the Department of Defense. The program was previously metered to as the Joint Advanced Strike Technology (JAST) Program. The tests at the OARF included: engine thrust calibrations out of ground effect, measurements of individual nozzle jet pressure decay characteristics, and jet-induced hover force and moment measurements in and out of ground effect. The engine calibrations provide data correlating propulsion system throttle and nozzle settings to thrust forces and moments for the bare fuselage with the wings, canards, and tails removed. This provides propulsive forces and moments while minimizing any of the effects due to the presence of the airframe. The engine calibrations were used later to determine thrust for hover testing at the OARF and for transition testing which took place in the NASA Ames 80 by 120 foot Wind Tunnel. The jet decay characteristics reflect the jet entrainment properties and are related to the aircraft suckdown characteristics. The JSF program provided the opportunity to obtain model scale effects using two models; one at small scale and one at large scale. Examples of data from these tests will be presented out of ground effect which will demonstrate the effect of scale. For one JSF configuration, two small-scale models and one large-scale model were tested and obtained different values for the lift loss out of ground effect. These differences were examined and are found to be largely dependent on the jet efflux characteristics. The jet-induced hover forces and moments are presented in and out of ground effect. For the hover testing the model is methodically built up from the bare fuselage, to include the wings, canards, and vertical tails, to determine the effects of each. Other components such as weapons bay doors, landing gear doors, and other lift improvement devices and their effect on the jet-induced forces and moments are examined.
In order to alleviate future congestion and increase the capacity of the future National Air Tran... more In order to alleviate future congestion and increase the capacity of the future National Air Transportation System, innovative air vehicles that implement new procedures in the Terminal Radar Approach Control (TRACON) airspace are necessary. With the capability to take-off and land in less than 2,000 feet, and yet cruise efficiently at Mach = 0.8 or higher, the Extreme Short Take-Off and Landing (ESTOL) aircraft is such a vehicle. This aircraft has the potential to fly in and out of crowded hub airports by using the unoccupied airspace and the underutilized runways and tarmac currently unused by the Conventional TakeOff and Landing (CTOL) transports (Reference 1). Additionally, by flying Simultaneous, Non-Interfering (SNI) take-off and approach procedures, the number of arrival and departure streams for a given airport increases while still maintaining safety and potentially reducing the impact of the ground noise footprint on sensitive areas of the community. Due to the unconventional and yet untried nature of the SNI approach (Reference 2), many issues exist that will need to be explored. These issues include: operational feasibility, measurements of the noise propagation to the local community, pilot handling quality and workload assessment, and passenger ride acceptance. On September 10, 2005, a flight test was conducted at Rogers Dry Lake Bed within Edwards Air Force Base of an Air Force Flight Test Center C-17 Globemaster III flying various landing approaches. These approaches varied from the standard 140 knot straight-in landing approach with a three degree glide slope in two ways; one of the approaches was flown like a conventional approach, but was flown at a steeper glide path angle of 5.5 degrees and airspeed between 125 and 130 knots. The other approach was flown with the aircraft remaining at a higher altitude of 3,000 ft Absolute Ground Level (AGL) until the aircraft was above the landing runway threshold. The aircraft then made a spiraling, descending 360 degree left hand turn with a descent angle of 5.5 degrees, a turn radius of about ¾ of a mile, a bank angle of about 20 degrees, and an overall flight speed of about 120 knots. At the end of the 360 degree turn the aircraft was back to the threshold, on the runway heading angle, and at the appropriate decision height of 250 ft (Figure 1). Although the C-17 did not fly as slow in the terminal airspace as the future ESTOL aircraft (65 – 85 knots), these landing approaches were representative of the ESTOL SNI approach. Additionally, all of these approaches were flown under Visual Flight Rules, with the understanding that implementation for a future ESTOL would require an all-weather capability comparable to current CTOL traffic. This paper addresses the operational issues, the handling quality and workload, and the passenger ride acceptance examined during this test. Other papers examine in more detail the community noise reduction potential from the SNI approach (Reference 3), the noise measurement techniques used during this test (Reference 4), and the mathematical modeling of the flight track (Reference 5). This paper will discuss the initial work conducted in the NASA Dryden C-17 simulator to program the Flight Management Computer (FMC) to fly the approach on autopilot, and the changes that became necessary during the actual flight when the crosswinds were higher than expected and the autopilot could not maintain the ground track. This
In order to meet the goals of reducing noise, emissions, and fuel burn, the Hybrid Wing Body (HWB... more In order to meet the goals of reducing noise, emissions, and fuel burn, the Hybrid Wing Body (HWB) will require revolutionary improvements in aerodynamics, acoustics, and structural design. Reducing or eliminating the traditional "tube" design fuselage offers a significant improvement in aerodynamic efficiency. The use of embedded engines offers the possibility of reducing radiated noise to the community while at the same time alleviating separation of the airflow over the wing. Reducing or eliminating empennage surfaces offers the possibility to reduce skin friction, form and trim drag during cruise while reducing structural weight. Essentially, the HWB offers the potential for significant improvements by using a multidisciplinary , highly integrated approach to aircraft design. For In designing HWB concepts that includes Cruise Efficient Short TakeOff and Landing (CESTOL) characteristics, some performance issues have been identified. The tendency for the powered lift system to generate nose down pitching moments makes it difficult to trim the HWB at low takeoff speeds without a horizontal tail, however the inclusion of a tail reduces efficiency due to the short longitudinal moment arm a HWB aircraft typically would have. Another issue stems from the desire for the HWB aircraft to use buried engines for noise mitigation purposes, but the need to efficiently vector thrust for short field performance means that a nacelle or off body mounted propulsion system may be preferred. Not all of the design integration issues are detrimental. For example, the large internal wing volume of the HWB provides more space for the powered-lift system than conventional tube-with-wing configurations with smaller wing areas. This paper will examine some of these issues of integrating CESTOL performance into a HWB aircraft. It will look at the potential advantages of a HWB CESTOL, examine areas of conflicting requirements, and offer potential solutions to mitigating these conflicts, or at least present a possible path to a solution. It will also look at the process being used in NASA's Subsonic Fixed Wing Project to develop new tools and modeling techniques for developing new designs for HWB CESTOL and validating those tools through experiments and wind tunnel tests in cooperation with industry partners and through NASA Research Announcements (NRA).
The Environmentally Responsible Aviation (ERA) Project within NASA’s Aeronautics Research Mission... more The Environmentally Responsible Aviation (ERA) Project within NASA’s Aeronautics Research Mission Directorate (ARMD) has identified metrics, goals, and objectives (MGOs) associated with noise, emission and fuel consumption of future air transport vehicles. As the ERA project progresses and lays the path to mature new technology, it becomes important to decompose these MGOs into aircraft performance requirements for which technology can be identified and worked to establish that level of performance, and achieve a Technology Readiness Level (TRL) of 6 appropriate for flying a new aircraft in a relevant environment. Optimizing the performance of the ERA aircraft during the take-off, climb, transition, descent and landing phases, what are being called, “Terminal Area Operations”, is not the primary objective of the ERA project since the majority of the mission takes place during the en route or cruise phase. Due to this, optimizing requirements such as cruise drag and fuel consumption become crucial to meeting the ERA MGOs and will require a significant effort. However, the performance requirements in the terminal area phases still need to be considered. The terminal phases comprise merely 5% 10% of the entire mission but are critical to its overall success; a safe and efficient take-off, transition, and landing are mandatory for every flight. Therefore, it is understood that in the terminal area phases it may be necessary to accept trade-offs such as using a flap/high-lift system to fly slower and accept a higher level of drag or fuel consumption in order to assure a safer take-off and landing. Or, as another example, a minimum acceptable climb rate needed for operations in the congested terminal airspace may not be optimal compared to the minimum fuel burn climb rate the cruise-optimized design suggests. Lastly, there are community noise and landing and take-off (LTO) nitrous oxide pollution emissions MGOs for ERA that are directly impacted by terminal area performance. The community noise mitigation operations at Santa Ana / Orange County airport are examples of employing unusual operational procedures to reduce some of the perceived noise levels on the ground with the corresponding increase in fuel consumption and operational complexity compared to a standard take-off. Without an obvious set of dominant MGOs, determining the performance requirements and corresponding research priorities for terminal area operations become an exercise in systems engineering. In order to establish those priorities, a team of subject matter experts (SME) met at NASA Ames Research Center in Feb 2011. For 1 1⁄2 days the team met, discussed, and evaluated how terminal area performance criteria might have an impact on the ERA MGOs. A Quality Function Deployment (QFD) was used by the team to aid in the analysis as was a “brainernet” discussion. The SMEs also discussed some candidate technologies that have the potential to either improve the ERA performance, or at least, mitigate the “off-design” performance associated with flying in the terminal airspace. This paper explains the QFD process used, and examines some of these performance requirements, and how they might impact the ERA MGOs. It will also present some candidate technologies that were determined by the SMEs as potential to address significant terminal area performance issues and still meet the ERA MGOs.
This paper presents data obtained from a test of the mixed-flow vectored-thrust (MFVT) advanced s... more This paper presents data obtained from a test of the mixed-flow vectored-thrust (MFVT) advanced short takeoff and vertical landing (ASTOVL) concept conceived by McDonnell Douglas Corporation. The 5.3% scale model has a contoured body, main and auxiliary inlets, and a flat plate wing and tail. Additionally, angled nozzle sets were used to obtain jet-induced data at 90°, 81.2', and 63.7' flow deflections. All tests were conducted without lift improvement devices. Balance data provided jet-induced lift increments for model attitudes of 0' and approximately 5' model nose up, nose down, and roll. Variations in nozzle pressure ratio had little measurable effect on the jet-induced lift, whereas nozzle exit temperature had no measurable effect on the jet-induced lift. Empirical predictions compared favorably with jet-induced lift data obtained.
NASA Ames conducted a series tests of a large-scale powered model of Lockheed Martin Skunk Works&... more NASA Ames conducted a series tests of a large-scale powered model of Lockheed Martin Skunk Works' JSF STOVL configuration at the 80- by 120-Foot Wind Tunnel. The model uses a modified version of an F-16 fighter engine (a Pratt & Whitney F100-229 engine). To provide vertical flight capability, the Lockheed aircraft incorporates a forward fuselage mounted vertical lift fan in addition to an aft mounted vectoring nozzle all driven by a single engine. The lift fan is driven off the engine by means of a shaft and gear system. The data presented is for STOVL configuration 140, a wing-body-canard planform. The main goal of this testing was to obtain propulsion induced data for evaluating differences between small- and large-scale model testing during the transition flight regime between jet- and wing-borne flight. The data presented is from aerodynamic testing of the model in both the unpowered (engine-off) and powered (engine running) configurations. This data, when combined with the propulsion system thrust calibration data from the NASA Ames' Outdoor Aerodynamic Research Facility (OARF), is used to determine the propulsion induced effects during transition.
An external environment test for an AV-8B Harrier during hover and vertical operations was conduc... more An external environment test for an AV-8B Harrier during hover and vertical operations was conducted at NAWCAD at Patuxent River, Maryland in July 1997. Four boundary layer rakes were instrumented with static and total pressures, and thermocouples for measuring temperatures. These rakes were installed at 30, 50, 75, and 100 foot from the hover center. The 50 ft and 100 ft rakes were offset 20 deg from the other two to minimize interference effects. In order to measure a complete flowfield footprint, it was necessary to have the Harrier change its heading relative to the rakes from 0 to 180 deg. A 20 deg increment in azimuth was used. This permitted the four rakes to measure the flowfield at 72 locations relative to the aircraft. However, as the Harrier burns fuel, the hover thrust must be reduced by the pilot in order to maintain a constant height above ground. The typical test procedure employed was: (1) vertical takeoff at an initial heading; (2) 20 second hover dwell at that heading; (3) pedal turn to a second heading, followed by a 20 second dwell hover; (4) pedal turn to a third heading, followed by a 20 second dwell hover; and (5) vertical landing at the third heading. Additional information is contained in the original extended abstract.
The Jet Calibration and Hover Test Facility at NASA Ames has been constructed to perform small sc... more The Jet Calibration and Hover Test Facility at NASA Ames has been constructed to perform small scale experiments in hot gas ingestion and jet effects for STOVL aircraft. This new facility and how it is employed to examine the problems associated with STOVL configurations hovering in- and out-of-ground effect are presented. Some of the test procedures and results are described.
The existing methodology can reasonably predict the sum value of these four items for limited con... more The existing methodology can reasonably predict the sum value of these four items for limited configurations. The over estimation of the fountain lift (item 3) and the additional multi-jet suckdown (item 4) tend to cancel, giving a 2 1.2 in. 3 0.87 in. each (3.9 in. spacing) De = 1.22 in. 4 0.85 in. each (2.5 in. spacing) De = 1.20 in.
45th AIAA Aerospace Sciences Meeting and Exhibit, Jan 8, 2007
In order to determine the feasibility of a powered lift civilian transport aircraft that will emp... more In order to determine the feasibility of a powered lift civilian transport aircraft that will employ alternate approach and departure trajectories, NASA commissioned CENTRA Technology, Inc. to develop the Conceptual Aircraft Trajectory Simulator (CATS). This simulation processes the proposed trajectory by analyzing the input position points (latitude, longitude, and altitude) as well as the aircraft velocity at each point. CATS simulates the required angle of attack and thrust levels at each time step along with providing other parameters such as: component velocities, heading, flight path angle, bank angle, lift and drag factors. By using actual flight data acquired during the September 2005 C-17 Noise Mitigation Flight Test, the analysis verifies that the results from CATS generated simulations matched those of an actual flight.
In 2014, the Vertical Flight Society (VFS) organized a series of workshops on Transformative Vert... more In 2014, the Vertical Flight Society (VFS) organized a series of workshops on Transformative Vertical Flight (TVF) in collaboration with NASA, the American Institute of Aeronautics and Astronautics (AIAA) and the Society of Automotive Engineers (SAE). The intent was to build a community of aerospace professionals that included technical, regulatory, and business elements, organized into several working groups, to explore potential future air transportation systems with innovative vertical takeoff and landing (VTOL) aircraft. Between 2014 and 2020 the annual TVF workshops focused on systems that embody combinations of on-demand, electric and hybrid-electric propulsion and vertiport-capable configurations and designs while identifying areas of potential interdisciplinary collaborations and solicited expert opinions from the participants on the work and timeframes required to transform air transportation. The workshops and working groups served as the basis for developing an advocacy roadmap and white paper on TVF transportation systems, technology, and markets. Acknowledgments Dedication This white paper is dedicated to Mr. Michael Dudley, whose passion, enthusiasm, and motivation in the Transformative Vertical Flight Working Groups inspired us to pursue the revolution of eVTOL aircraft NASA TVF WG Sponsor Vertical Flight Society
The focus of the current research is to numerically predict an infrared image of a jet engine exh... more The focus of the current research is to numerically predict an infrared image of a jet engine exhaust plume, given field variables such as temperature, pressure, and exhaust plume constituents as a function of spatial position within the plume, and to compare this predicted image ...
The focus of this research is to numerically predict an infrared image of a jet engine exhaust pl... more The focus of this research is to numerically predict an infrared image of a jet engine exhaust plume, given field variables such as temperature, pressure, and exhaust plume constituents as a function of spatial position within the plume, and to compare this predicted image ...
Hover and ground-effect tests were conducted with the Lockheed-Martin Large Scale Powered Model (... more Hover and ground-effect tests were conducted with the Lockheed-Martin Large Scale Powered Model (LSPM) during June-November 1995 at the NASA Ames Research Center's Outdoor Aerodynamics Research Facility (OARF). This was done in support of the Joint Strike Fighter (JSF) Program being lead by the Department of Defense. The program was previously metered to as the Joint Advanced Strike Technology (JAST) Program. The tests at the OARF included: engine thrust calibrations out of ground effect, measurements of individual nozzle jet pressure decay characteristics, and jet-induced hover force and moment measurements in and out of ground effect. The engine calibrations provide data correlating propulsion system throttle and nozzle settings to thrust forces and moments for the bare fuselage with the wings, canards, and tails removed. This provides propulsive forces and moments while minimizing any of the effects due to the presence of the airframe. The engine calibrations were used later to determine thrust for hover testing at the OARF and for transition testing which took place in the NASA Ames 80 by 120 foot Wind Tunnel. The jet decay characteristics reflect the jet entrainment properties and are related to the aircraft suckdown characteristics. The JSF program provided the opportunity to obtain model scale effects using two models; one at small scale and one at large scale. Examples of data from these tests will be presented out of ground effect which will demonstrate the effect of scale. For one JSF configuration, two small-scale models and one large-scale model were tested and obtained different values for the lift loss out of ground effect. These differences were examined and are found to be largely dependent on the jet efflux characteristics. The jet-induced hover forces and moments are presented in and out of ground effect. For the hover testing the model is methodically built up from the bare fuselage, to include the wings, canards, and vertical tails, to determine the effects of each. Other components such as weapons bay doors, landing gear doors, and other lift improvement devices and their effect on the jet-induced forces and moments are examined.
In order to alleviate future congestion and increase the capacity of the future National Air Tran... more In order to alleviate future congestion and increase the capacity of the future National Air Transportation System, innovative air vehicles that implement new procedures in the Terminal Radar Approach Control (TRACON) airspace are necessary. With the capability to take-off and land in less than 2,000 feet, and yet cruise efficiently at Mach = 0.8 or higher, the Extreme Short Take-Off and Landing (ESTOL) aircraft is such a vehicle. This aircraft has the potential to fly in and out of crowded hub airports by using the unoccupied airspace and the underutilized runways and tarmac currently unused by the Conventional TakeOff and Landing (CTOL) transports (Reference 1). Additionally, by flying Simultaneous, Non-Interfering (SNI) take-off and approach procedures, the number of arrival and departure streams for a given airport increases while still maintaining safety and potentially reducing the impact of the ground noise footprint on sensitive areas of the community. Due to the unconventional and yet untried nature of the SNI approach (Reference 2), many issues exist that will need to be explored. These issues include: operational feasibility, measurements of the noise propagation to the local community, pilot handling quality and workload assessment, and passenger ride acceptance. On September 10, 2005, a flight test was conducted at Rogers Dry Lake Bed within Edwards Air Force Base of an Air Force Flight Test Center C-17 Globemaster III flying various landing approaches. These approaches varied from the standard 140 knot straight-in landing approach with a three degree glide slope in two ways; one of the approaches was flown like a conventional approach, but was flown at a steeper glide path angle of 5.5 degrees and airspeed between 125 and 130 knots. The other approach was flown with the aircraft remaining at a higher altitude of 3,000 ft Absolute Ground Level (AGL) until the aircraft was above the landing runway threshold. The aircraft then made a spiraling, descending 360 degree left hand turn with a descent angle of 5.5 degrees, a turn radius of about ¾ of a mile, a bank angle of about 20 degrees, and an overall flight speed of about 120 knots. At the end of the 360 degree turn the aircraft was back to the threshold, on the runway heading angle, and at the appropriate decision height of 250 ft (Figure 1). Although the C-17 did not fly as slow in the terminal airspace as the future ESTOL aircraft (65 – 85 knots), these landing approaches were representative of the ESTOL SNI approach. Additionally, all of these approaches were flown under Visual Flight Rules, with the understanding that implementation for a future ESTOL would require an all-weather capability comparable to current CTOL traffic. This paper addresses the operational issues, the handling quality and workload, and the passenger ride acceptance examined during this test. Other papers examine in more detail the community noise reduction potential from the SNI approach (Reference 3), the noise measurement techniques used during this test (Reference 4), and the mathematical modeling of the flight track (Reference 5). This paper will discuss the initial work conducted in the NASA Dryden C-17 simulator to program the Flight Management Computer (FMC) to fly the approach on autopilot, and the changes that became necessary during the actual flight when the crosswinds were higher than expected and the autopilot could not maintain the ground track. This
In order to meet the goals of reducing noise, emissions, and fuel burn, the Hybrid Wing Body (HWB... more In order to meet the goals of reducing noise, emissions, and fuel burn, the Hybrid Wing Body (HWB) will require revolutionary improvements in aerodynamics, acoustics, and structural design. Reducing or eliminating the traditional "tube" design fuselage offers a significant improvement in aerodynamic efficiency. The use of embedded engines offers the possibility of reducing radiated noise to the community while at the same time alleviating separation of the airflow over the wing. Reducing or eliminating empennage surfaces offers the possibility to reduce skin friction, form and trim drag during cruise while reducing structural weight. Essentially, the HWB offers the potential for significant improvements by using a multidisciplinary , highly integrated approach to aircraft design. For In designing HWB concepts that includes Cruise Efficient Short TakeOff and Landing (CESTOL) characteristics, some performance issues have been identified. The tendency for the powered lift system to generate nose down pitching moments makes it difficult to trim the HWB at low takeoff speeds without a horizontal tail, however the inclusion of a tail reduces efficiency due to the short longitudinal moment arm a HWB aircraft typically would have. Another issue stems from the desire for the HWB aircraft to use buried engines for noise mitigation purposes, but the need to efficiently vector thrust for short field performance means that a nacelle or off body mounted propulsion system may be preferred. Not all of the design integration issues are detrimental. For example, the large internal wing volume of the HWB provides more space for the powered-lift system than conventional tube-with-wing configurations with smaller wing areas. This paper will examine some of these issues of integrating CESTOL performance into a HWB aircraft. It will look at the potential advantages of a HWB CESTOL, examine areas of conflicting requirements, and offer potential solutions to mitigating these conflicts, or at least present a possible path to a solution. It will also look at the process being used in NASA's Subsonic Fixed Wing Project to develop new tools and modeling techniques for developing new designs for HWB CESTOL and validating those tools through experiments and wind tunnel tests in cooperation with industry partners and through NASA Research Announcements (NRA).
The Environmentally Responsible Aviation (ERA) Project within NASA’s Aeronautics Research Mission... more The Environmentally Responsible Aviation (ERA) Project within NASA’s Aeronautics Research Mission Directorate (ARMD) has identified metrics, goals, and objectives (MGOs) associated with noise, emission and fuel consumption of future air transport vehicles. As the ERA project progresses and lays the path to mature new technology, it becomes important to decompose these MGOs into aircraft performance requirements for which technology can be identified and worked to establish that level of performance, and achieve a Technology Readiness Level (TRL) of 6 appropriate for flying a new aircraft in a relevant environment. Optimizing the performance of the ERA aircraft during the take-off, climb, transition, descent and landing phases, what are being called, “Terminal Area Operations”, is not the primary objective of the ERA project since the majority of the mission takes place during the en route or cruise phase. Due to this, optimizing requirements such as cruise drag and fuel consumption become crucial to meeting the ERA MGOs and will require a significant effort. However, the performance requirements in the terminal area phases still need to be considered. The terminal phases comprise merely 5% 10% of the entire mission but are critical to its overall success; a safe and efficient take-off, transition, and landing are mandatory for every flight. Therefore, it is understood that in the terminal area phases it may be necessary to accept trade-offs such as using a flap/high-lift system to fly slower and accept a higher level of drag or fuel consumption in order to assure a safer take-off and landing. Or, as another example, a minimum acceptable climb rate needed for operations in the congested terminal airspace may not be optimal compared to the minimum fuel burn climb rate the cruise-optimized design suggests. Lastly, there are community noise and landing and take-off (LTO) nitrous oxide pollution emissions MGOs for ERA that are directly impacted by terminal area performance. The community noise mitigation operations at Santa Ana / Orange County airport are examples of employing unusual operational procedures to reduce some of the perceived noise levels on the ground with the corresponding increase in fuel consumption and operational complexity compared to a standard take-off. Without an obvious set of dominant MGOs, determining the performance requirements and corresponding research priorities for terminal area operations become an exercise in systems engineering. In order to establish those priorities, a team of subject matter experts (SME) met at NASA Ames Research Center in Feb 2011. For 1 1⁄2 days the team met, discussed, and evaluated how terminal area performance criteria might have an impact on the ERA MGOs. A Quality Function Deployment (QFD) was used by the team to aid in the analysis as was a “brainernet” discussion. The SMEs also discussed some candidate technologies that have the potential to either improve the ERA performance, or at least, mitigate the “off-design” performance associated with flying in the terminal airspace. This paper explains the QFD process used, and examines some of these performance requirements, and how they might impact the ERA MGOs. It will also present some candidate technologies that were determined by the SMEs as potential to address significant terminal area performance issues and still meet the ERA MGOs.
This paper presents data obtained from a test of the mixed-flow vectored-thrust (MFVT) advanced s... more This paper presents data obtained from a test of the mixed-flow vectored-thrust (MFVT) advanced short takeoff and vertical landing (ASTOVL) concept conceived by McDonnell Douglas Corporation. The 5.3% scale model has a contoured body, main and auxiliary inlets, and a flat plate wing and tail. Additionally, angled nozzle sets were used to obtain jet-induced data at 90°, 81.2', and 63.7' flow deflections. All tests were conducted without lift improvement devices. Balance data provided jet-induced lift increments for model attitudes of 0' and approximately 5' model nose up, nose down, and roll. Variations in nozzle pressure ratio had little measurable effect on the jet-induced lift, whereas nozzle exit temperature had no measurable effect on the jet-induced lift. Empirical predictions compared favorably with jet-induced lift data obtained.
NASA Ames conducted a series tests of a large-scale powered model of Lockheed Martin Skunk Works&... more NASA Ames conducted a series tests of a large-scale powered model of Lockheed Martin Skunk Works' JSF STOVL configuration at the 80- by 120-Foot Wind Tunnel. The model uses a modified version of an F-16 fighter engine (a Pratt & Whitney F100-229 engine). To provide vertical flight capability, the Lockheed aircraft incorporates a forward fuselage mounted vertical lift fan in addition to an aft mounted vectoring nozzle all driven by a single engine. The lift fan is driven off the engine by means of a shaft and gear system. The data presented is for STOVL configuration 140, a wing-body-canard planform. The main goal of this testing was to obtain propulsion induced data for evaluating differences between small- and large-scale model testing during the transition flight regime between jet- and wing-borne flight. The data presented is from aerodynamic testing of the model in both the unpowered (engine-off) and powered (engine running) configurations. This data, when combined with the propulsion system thrust calibration data from the NASA Ames' Outdoor Aerodynamic Research Facility (OARF), is used to determine the propulsion induced effects during transition.
An external environment test for an AV-8B Harrier during hover and vertical operations was conduc... more An external environment test for an AV-8B Harrier during hover and vertical operations was conducted at NAWCAD at Patuxent River, Maryland in July 1997. Four boundary layer rakes were instrumented with static and total pressures, and thermocouples for measuring temperatures. These rakes were installed at 30, 50, 75, and 100 foot from the hover center. The 50 ft and 100 ft rakes were offset 20 deg from the other two to minimize interference effects. In order to measure a complete flowfield footprint, it was necessary to have the Harrier change its heading relative to the rakes from 0 to 180 deg. A 20 deg increment in azimuth was used. This permitted the four rakes to measure the flowfield at 72 locations relative to the aircraft. However, as the Harrier burns fuel, the hover thrust must be reduced by the pilot in order to maintain a constant height above ground. The typical test procedure employed was: (1) vertical takeoff at an initial heading; (2) 20 second hover dwell at that heading; (3) pedal turn to a second heading, followed by a 20 second dwell hover; (4) pedal turn to a third heading, followed by a 20 second dwell hover; and (5) vertical landing at the third heading. Additional information is contained in the original extended abstract.
The Jet Calibration and Hover Test Facility at NASA Ames has been constructed to perform small sc... more The Jet Calibration and Hover Test Facility at NASA Ames has been constructed to perform small scale experiments in hot gas ingestion and jet effects for STOVL aircraft. This new facility and how it is employed to examine the problems associated with STOVL configurations hovering in- and out-of-ground effect are presented. Some of the test procedures and results are described.
The existing methodology can reasonably predict the sum value of these four items for limited con... more The existing methodology can reasonably predict the sum value of these four items for limited configurations. The over estimation of the fountain lift (item 3) and the additional multi-jet suckdown (item 4) tend to cancel, giving a 2 1.2 in. 3 0.87 in. each (3.9 in. spacing) De = 1.22 in. 4 0.85 in. each (2.5 in. spacing) De = 1.20 in.
Uploads
Papers by Craig Hange