Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781725814394
Category :
Languages : en
Pages : 34
Book Description
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...
Summary and Recent Results from the NASA Advanced High Speed Propeller Research Program
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781725572805
Category :
Languages : en
Pages : 34
Book Description
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...
Publisher: Createspace Independent Publishing Platform
ISBN: 9781725572805
Category :
Languages : en
Pages : 34
Book Description
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...
Summary and Recent Results from the NASA Advanced High-speed Propeller Research Program
Author: Glenn A. Mitchell
Publisher:
ISBN:
Category :
Languages : en
Pages : 34
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 34
Book Description
NASA Technical Paper
Author:
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 36
Book Description
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 36
Book Description
Advanced Turboprop Project
Author: Roy D. Hager
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 130
Book Description
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 130
Book Description
Scientific and Technical Aerospace Reports
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 892
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 892
Book Description
Advanced Turboprop Project
Author: Roy D. Hager
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 140
Book Description
Publisher:
ISBN:
Category : Airplanes
Languages : en
Pages : 140
Book Description
NASA Technical Memorandum
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 492
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 492
Book Description
NASA SP.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 700
Book Description
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 700
Book Description
Aeroacoustics of Flight Vehicles
Author: Harvey H. Hubbard
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 620
Book Description
Publisher:
ISBN:
Category : Aerodynamic noise
Languages : en
Pages : 620
Book Description
NASA Advanced Propeller Research
Author: National Aeronautics and Space Administration (NASA)
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722396657
Category :
Languages : en
Pages : 36
Book Description
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...
Publisher: Createspace Independent Publishing Platform
ISBN: 9781722396657
Category :
Languages : en
Pages : 36
Book Description
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...