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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 73 records · Page 4

A Second Generation Swirl-Venturi Lean Direct Injection Combustion Concept

A low-NO (sub x) aircraft gas turbine engine combustion concept was developed and tested. The concept is a second generation swirl-venturi lean direct injection (SV-LDI) concept. LDI is a lean-burn combustion concept in which the fuel is injected directly into the flame zone. Three second generation SV-LDI configurations were developed. All three were based on the baseline 9-point SV-LDI configuration reported previously. These second generation configurations had better low power operability than the baseline 9-point configuration. Two of these second generation configurations were tested in a NASA Glenn Research Center flametube; these two configurations are called the at dome and 5-recess configurations. Results show that the 5-recess configuration generally had lower NO (sub x) emissions than the flat dome configuration. Correlation equations were developed for the flat dome configuration so that the landing-takeoff NO (sub x) emissions could be estimated. The flat dome landing-takeoff NO (sub x) is estimated to be 87-88 percent below the CAEP/6 standards, exceeding the ERA project goal of 75 percent reduction.

Tacina, Kathleen M.↗

Takeoff and landing performance and noise measurements of a deflected slipstream STOL airplane with interconnected propellers and rotating cylinder flaps

A YOV-10A aircraft was modified to incorporate rotating cylinder flaps and interconnected propellers with Lycoming T-53-L11 engines. Flight tests were made to evaluate the low speed handling qualities and performance characteristics. The flight test results indicated that landings could be made with approach speeds of 55 to 65 knots (CL = 4.5) and descent angles of 6 deg to 8 deg for total flap angles of 60 deg to 75 deg. At higher flap angles, deterioration of stability and control characteristics precluded attempts at landing. The noise level on the ground under an 8 deg landing approach path was below 86 PNdB at distances beyond 1 nautical mile from touchdown. Takeoffs were made with 30 deg to 45 deg flaps at lift off speeds of 75 to 80 knots and climb angles of 4 deg to 8 deg. Noise levels were below 83 PNdB at 3.5 nautical miles from the start of ground roll.

Weiberg, J. A.↗

A Comparison of Three Second-generation Swirl-Venturi Lean Direct Injection Combustor Concepts

Three variations of a low emissions aircraft gas turbine engine combustion concept were developed and tested. The concept is a second generation swirl-venturi lean direct injection (SV-LDI) concept. LDI is a lean-burn combustion concept in which the fuel is injected directly into the flame zone. All three variations were based on the baseline 9- point SV-LDI configuration reported previously. The three second generation SV-LDI variations are called the 5-recess configuration, the flat dome configuration, and the 9- recess configuration. These three configurations were tested in a NASA Glenn Research Center medium pressure flametube. All three second generation variations had better low power operability than the baseline 9-point configuration. All three configurations had low NO(sub x) emissions, with the 5-recess configuration generally having slightly lower NO(x) than the flat dome or 9-recess configurations. Due to the limitations of the flametube that prevented testing at pressures above 20 atm, correlation equations were developed for the at dome and 9-recess configurations so that the landing-takeoff NO(sub x) emissions could be estimated. The flat dome and 9-recess landing-takeoff NO(x) emissions are estimated to be 81-88% below the CAEP/6 standards, exceeding the project goal of 75% reduction.

combustor↗

CFD Simulations of Landing and Takeoff CRM High-Lift Configurations

Numerical simulations have been performed for a conventional high-lift version of the Common Research Model (CRM) model corresponding to landing and take- off configurations. Computed values of lift and drag for the landing configuration are compared with the experimental data acquired in the 14- by 22-Foot Subsonic Tunnel (14×22) at the NASA Langley Research Center (LaRC). Simulations replicated the experimentally observed improvements in the lift characteristics in the presence of a nacelle chine. Flow visualization images indicate that vortices generated by the nacelle chine reduce flow separation regions on the upper surface of the wing at higher angles of attack. Based on such observations, the take-off configuration considered is also equipped with a nacelle chine, and testing of this configuration is planned in the 14×22 tunnel in near future. Preliminary solutions are also presented to explore the feasibility of using a localized flap gap blowing (LFGB) active flow control concept for improving the aerodynamic performance at take-off conditions.

aerodynamics↗

CFD Simulations of Landing and Takeoff CRM High-Lift Configurations

Numerical simulations have been performed for a conventional high-lift version of the Common Research Model (CRM) model corresponding to landing and take- off configurations. Computed values of lift and drag for the landing configuration are compared with the experimental data acquired in the 14- by 22-Foot Subsonic Tunnel (14×22) at the NASA Langley Research Center (LaRC). Simulations replicated the experimentally observed improvements in the lift characteristics in the presence of a nacelle chine. Flow visualization images indicate that vortices generated by the nacelle chine reduce flow separation regions on the upper surface of the wing at higher angles of attack. Based on such observations, the take-off configuration considered is also equipped with a nacelle chine, and testing of this configuration is planned in the 14×22 tunnel in near future. Preliminary solutions are also presented to explore the feasibility of using a localized flap gap blowing (LFGB) active flow control concept for improving the aerodynamic performance at take-off conditions.

aerodynamics↗

Guidance for a tilt rotor VTOL aircraft during takeoff and landing

A perturbation guidance scheme is developed to keep a tilt-rotor VTOL aircraft close to a predetermined nominal flight path during take-off and landing. A simulation of the guidance scheme applied to the Bell Model 266 tilt-rotor VTOL gave satisfactory behavior in the presence of initial errors and wind disturbances.

Gupta, N. K.↗

Response to actual and simulated recordings of conventional takeoff and landing jet aircraft

Comparability between noise characteristics of synthesized recordings of aircraft in flight and actual recordings were investigated. Although the synthesized recordings were more smoothly time-varying than the actual recordings and the synthesizer could not produce a comb-filter effect that was present in the actual recordings, results supported the conclusion that annoyance response is comparable to the synthesized and actual recordings. A correction for duration markedly improved the validity of engineering calculation procedures designed to measure noise annoyance. Results led to the conclusion that the magnitude estimation psychophysical method was a highly reliable approach for evaluating engineering calculation procedures designed to measure noise annoyance. For repeated presentations of pairs of actual recordings, differences between judgment results for identical signals ranged from 0.0 to 0.5 db.

Mabry, J. E.↗

Vertical Takeoff and Landing (VTOL) propulsion technology

Propulsion problems and advanced technology requirements of VTOL aircraft are discussed. Specific topics covered include inlets with high angle of attack capability, rapid thrust modulation fans, and propulsion-system/aircraft-control integration.

Carl C. Ciepluch↗

A mathematical model for Vertical Attitude Takeoff and Landing (VATOL) aircraft simulation. Volume 2: Model equations and base aircraft data

Equations incorporated in a VATOL six degree of freedom off-line digital simulation program and data for the Vought SF-121 VATOL aircraft concept which served as the baseline for the development of this program are presented. The equations and data are intended to facilitate the development of a piloted VATOL simulation. The equation presentation format is to state the equations which define a particular model segment. Listings of constants required to quantify the model segment, input variables required to exercise the model segment, and output variables required by other model segments are included. In several instances a series of input or output variables are followed by a section number in parentheses which identifies the model segment of origination or termination of those variables.

Fortenbaugh, R. L.↗

Piloted simulation of hover and transition of a vertical attitude takeoff and landing aircraft

Piloted simulation studies of candidate control systems for VATOL aircraft were conducted on a six degree of freedom simulator. Hover and transitions from wing-born to hovering flight were performed, with and without turbulence, on a representative high performance fighter configuration. Deflection of the rear engine nozzle provided pitch and yaw control moments in concert with reaction controls for roll. Unique motion cues in hover result from the vertical displacement of the cockpit and the thrust vectoring nozzles. Abundant control power available with moderate engine nozzle deflection combined with rate feedback for stability augmentation provided very satisfactory control.

Hill, G. C.↗

Simulating Instrument Helicopter Takeoffs And Landings

Advantages and disadvantages of computer-based simulations reviewed. Report reviews current methods for evaluation of TERP's. Discusses feasibility, benefits, liabilities of substitution of electronically controlled flight-simulation equipment for flight tests.

Phatak, Anil V.↗

Runway Independent Aircraft Extremely Short Takeoff and Landing Regional Airliner: The Model 110

Airports throughout the United States are plagued with growing congestion. With the increase in air traffic predicted in the next few years, congestion will worsen. The accepted solution of building larger airplanes to carry more travelers is no longer a viable option, as airports are unable to accommodate larger aircraft without expensive infrastructure changes. Past NASA research has pointed to the need for a new approach, which can economically and safely utilize smaller airports. To study this option further, NASA requested the California Polytechnic State University at San Luis Obispo (Cal Poly/SLO) to design a baseline aircraft to be used for system studies. The requirements put forth by NASA are summarized. The design team was requested to create a demonstrator vehicle, which could be built without requiring enabling technology development. To this end, NASA requested that the tested and proven high-lift system of the Boeing C-17 Globemaster III be combined with the fuselage of the BAe-146. NASA also requested that Cal Poly determine the availability and usability of underutilized airports starting with California, then expanding if time and funds permitted to the U.S.

Hall, David W.↗

Runway Independent Aircraft Extremely Short Takeoff and Landing

This report Summarizes the work done is support of NASA/Ames Runway Independent Aircraft Research during the summer of 2003. This work centered on the tasks laid out by the Statement of Work, which was to: Identify and assess operational scenarios including airport air and ground operations and how RIA operations would interface; 2) Identify critical technologies and create a list of technologies that might be pushed to provide a quantum jump in operating economy, reliability, and safety should sufficient finding be available; 3) Create public domain powered high lift methodologies; and 4) Identify and assess vehicle concepts that provide innovative approaches to RIA operations. All these tasks were accomplished, with certain areas needing additional exploration in future grant work. Three designs were analyzed to provide strawman configurations for the RIA operations. All three aircraft carried 60 passengers, with a stage length of 1,000 nautical miles. They were capable of operating with a balanced field length of 2000 feet or less. Three different technology approaches were explored. The first, the Model 115, was a mid-wing USB design, developed as a near-term, low risk concept. The second aircraft, the EMAX, used a directed thrust system, was a far-term, high-risk approach. The third configuration was the Model 114, whose development began in summer 2002. In addition, further research was conducted on issues related to STOL operations, such as noise concerns, SNI operations, and other areas of interest.

Hall, David W.↗

Computational Evaluation of Inlet Distortion on an Ejector Powered Hybrid Wing Body at Takeoff and Landing Conditions

Due to the aft, upper surface engine location on the Hybrid Wing Body (HWB) planform, there is potential to shed vorticity and separated wakes into the engine when the vehicle is operated at off-design conditions and corners of the envelope required for engine and airplane certification. CFD simulations were performed of the full-scale reference propulsion system, operating at a range of inlet flow rates, flight speeds, altitudes, angles of attack, and angles of sideslip to identify the conditions which produce the largest distortion and lowest pressure recovery. Pretest CFD was performed by NASA and Boeing, using multiple CFD codes, with various turbulence models. These data were used to make decisions regarding model integration, characterize inlet flow distortion patterns, and help define the wind tunnel test matrix. CFD was also performed post-test; when compared with test data, it was possible to make comparisons between measured model-scale and predicted full-scale distortion levels. This paper summarizes these CFD analyses.

Wind Tunnel Testing↗