Download or read book NASA Advanced Propeller Research written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-07 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic and aerodynamic research at NASA Lewis Research Center on advanced propellers is reviewed including analytical and experimental results on both single and counterrotation. Computational tools used to calculate the detailed flow and acoustic fields are described along with wind tunnel tests to obtain data for code verification. Results from two kinds of experiments are reviewed: (1) performance and near field noise at cruise conditions as measured in the NASA Lewis 8- by 6-foot Wind Tunnel; and (2) far field noise and performance for takeoff/approach conditions as measured in the NASA Lewis 9- by 15-foot Anechoic Wind Tunnel. Detailed measurements of steady blade surface pressures are described along with vortex flow phenomena at off-design conditions. Near field noise at cruise is shown to level out or decrease as tip relative Mach number is increased beyond 1.15. Counterrotation interaction noise is shown to be a dominant source at takeoff but a secondary source at cruise. Effects of unequal rotor diameters and rotor-to-rotor spacing on interaction noise are also illustrated. Comparisons of wind tunnel acoustic measurements to flight results are made. Finally, some future directions in advanced propeller research such as swirl recovery vanes, higher sweep, forward sweep, and ducted propellers are discussed. Groeneweg, John F. and Bober, Lawrence J. Glenn Research Center RTOP 535-03-01...
Download or read book Nasa Advanced Propeller Research written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Acoustic and aerodynamic research at NASA Lewis Research Center on advanced propellers is reviewed including analytical and experimental results on both single and counterrotation. Computational tools used to calculate the detailed flow and acoustic i e l d s a r e described along with wind tunnel tests to obtain data for code verification . Results from two kinds of experiments are reviewed: ( 1 ) performance and near field noise at cruise conditions as measured in the NASA Lewis 8-by 6-Foot Wind Tunnel and ( 2 ) farfield noise and performance for takeoff/approach conditions as measured in the NASA Lewis 9-by 15-Font Anechoic Wind Tunnel. Detailed measurements of steady blade surface pressures are described along with vortex flow phenomena at off design conditions . Near field noise at cruise is shown to level out or decrease as tip relative Mach number is increased beyond 1.15. Counterrotation interaction noise is shown to be a dominant source at take off but a secondary source at cruise. Effects of unequal rotor diameters and rotor-to-rotor spacing on interaction noise a real so illustrated. Comparisons of wind tunnel acoustic measurements to flight results are made. Finally, some future directions in advanced propeller research such as swirl recovery vanes, higher sweep, forward sweep, and ducted propellers are discussed.
Download or read book Summary and Recent Results from the NASA Advanced High Speed Propeller Research Program written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-20 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced high-speed propellers offer large performance improvements for aircraft that cruise in the Mach 0.7 to 0.8 speed regime. The current status of the NASA research program on high-speed propeller aerodynamics, acoustics, and aeroelastics is described. Recent wind tunnel results for five 8- to 10-blade advanced models are compared with analytical predictions. Test results show that blade sweep was important in achieving net efficiencies near 80 percent at Mach 0.8 and reducing near-field cruise noise by dB. Lifting line and lifting surface aerodynamic analysis codes are under development and some initial lifting line results are compared with propeller force and probe data. Some initial laser velocimeter measurements of the flow field velocities of an 8-bladed 45 deg swept propeller are shown. Experimental aeroelastic results indicate that cascade effects and blade sweep strongly affect propeller aeroelastic characteristics. Comparisons of propeller near-field noise data with linear acoustic theory indicate that the theory adequate predicts near-field noise for subsonic tip speeds but overpredicts the noise for supersonic tip speeds. Potential large gains in propeller efficiency of 7 to 11 percent at Mach 0.8 may be possible with advanced counter-rotation propellers. Mitchell, G. A. and Mikkelson, D. C. Glenn Research Center NASA-TM-82891, E-1269, NAS 1.15:82891 RTOP 535-03-12...
Download or read book Summary and Recent Results from the NASA Advanced High speed Propeller Research Program written by Glenn A. Mitchell and published by . This book was released on 1982 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeroacoustics of Flight Vehicles written by Harvey H. Hubbard and published by . This book was released on 1991 with total page 620 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book NASA Technical Paper written by and published by . This book was released on 1980 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Turboprop Project written by Roy D. Hager and published by . This book was released on 1988 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Comparison of Propeller Cruise Noise Data Taken in the NASA Lewis 8 By 6 Foot Wind Tunnel with Other Tunnel and Flight Data written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-16 with total page 38 pages. Available in PDF, EPUB and Kindle. Book excerpt: The noise of advanced high speed propeller models measured in the NASA 8- by 6-foot wind tunnel has been compared with model propeller noise measured in another tunnel and with full-scale propeller noise measured in flight. Good agreement was obtained for the noise of a model counterrotation propeller tested in the 8- by 6-foot wind tunnel and in the acoustically treated test section of the Boeing Transonic Wind Tunnel. This good agreement indicates the relative validity of taking cruise noise data on a plate in the 8- by 6-foot wind tunnel compared with the free-field method in the Boeing tunnel. Good agreement was also obtained for both single rotation and counter-rotation model noise comparisons with full-scale propeller noise in flight. The good scale model to full-scale comparisons indicate both the validity of the 8- by 6-foot wind tunnel data and the ability to scale to full size. Boundary layer refraction on the plate provides a limitation to the measurement of forward arc noise in the 8- by 6-foot wind tunnel at the higher harmonics of the blade passing tone. The use of a validated boundary layer refraction model to adjust the data could remove this limitation. Dittmar, James H. Glenn Research Center NASA-TM-101976, E-4676, NAS 1.15:101976, AIAA PAPER 89-1059 RTOP 535-03-01...
Download or read book Summary of Recent NASA Propeller Research written by Daniel C. Mikkelson and published by . This book was released on 1984 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aeropropulsion Facilities at the NASA Lewis Research Center written by Lewis Research Center and published by . This book was released on 1995 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Advanced Turboprop Project written by Roy D. Hager and published by . This book was released on 1988 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Theory of Propellers written by Theodore Theodorsen and published by . This book was released on 1944 with total page 184 pages. Available in PDF, EPUB and Kindle. Book excerpt: Summary: A technical method is given for calculating the axial interference velocity of a propeller. The method involves the use of certain weight functions P, Q, and F. Numerical values for the weight functions are given for two-blade, three-blade, and six-blade propellers.
Download or read book The Power for Flight written by Jeremy R. Kinney and published by Government Printing Office. This book was released on 2018-02-15 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: The NACA and aircraft propulsion, 1915-1958 -- NASA gets to work, 1958-1975 -- The shift toward commercial aviation, 1966-1975 -- The quest for propulsive efficiency, 1976-1989 -- Propulsion control enters the computer era, 1976-1998 -- Transiting to a new century, 1990-2008 -- Toward the future
Download or read book NASA Advanced Aeronautics Design Solar Powered Remotely Piloted Vehicle written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-27 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: Environmental problems such as the depletion of the ozone layer and air pollution demand a change in traditional means of propulsion that is sensitive to the ecology. Solar powered propulsion is a favorable alternative that is both ecologically harmless as well as cost effective. Integration of solar energy into designs ranging from futuristic vehicles to heating is beneficial to society. The design and construction of a Multi-Purpose Remotely Piloted Vehicle (MPRPV) seeks to verify the feasibility of utilizing solar propulsion as a primary fuel source. This task has been a year long effort by a group of ten students, divided into five teams, each dealing with different aspects of the design. The aircraft was designed to take-off, climb to the design altitude, fly in a sustained figure-eight flight path, and cruise for approximately one hour. This mission requires flight at Reynolds numbers between 150,000 and 200,000 and demands special considerations in the aerodynamic design in order to achieve flight in this regime. Optimal performance requires a light weight configuration with both structural integrity and maximum power availability. The structure design and choice of solar cells for the propulsion was governed by the weight, efficiency, and cost considerations. The final design is a MPRPV weighting 35 N which cruises 7 m/s at the design altitude of 50 m. The configuration includes a wing composed of balsa and foam NACA 6409 airfoil sections and carbon fiber spars, a tail of similar construction, and a truss structure fuselage. The propulsion system consists of 98 10 percent efficient solar cells donated by Mobil Solar, a NiCad battery for energy storage, and a folding propeller regulated by a lightweight and efficient control system. The airfoils and propeller chosen for the design were research and tested during the design process. Elario, David S. and Guillmette, Neal H. and Lind, Gregory S. and Webster, Jonathan D. and Ferreira, Michael J. and Konstantakis, ..
Download or read book Advanced Aerodynamics and Active Controls Selected NASA Research written by and published by . This book was released on 1981 with total page 196 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Computation of the Tip Vortex Flowfield for Advanced Aircraft Propellers written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-06 with total page 62 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tip vortex flowfield plays a significant role in the performance of advanced aircraft propellers. The flowfield in the tip region is complex, three-dimensional and viscous with large secondary velocities. An analysis is presented using an approximate set of equations which contains the physics required by the tip vortex flowfield, but which does not require the resources of the full Navier-Stokes equations. A computer code was developed to predict the tip vortex flowfield of advanced aircraft propellers. A grid generation package was developed to allow specification of a variety of advanced aircraft propeller shapes. Calculations of the tip vortex generation on an SR3 type blade at high Reynolds numbers were made using this code and a parametric study was performed to show the effect of tip thickness on tip vortex intensity. In addition, calculations of the tip vortex generation on a NACA 0012 type blade were made, including the flowfield downstream of the blade trailing edge. Comparison of flowfield calculations with experimental data from an F4 blade was made. A user's manual was also prepared for the computer code (NASA CR-182178). Tsai, Tommy M. and Dejong, Frederick J. and Levy, Ralph Unspecified Center...
Download or read book The History of the XV 15 Tilt Rotor Research Aircraft written by Martin D. Maisel and published by . This book was released on 2000 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
