WIND TUNNEL PERFORMANCE OF FOUR ENERGY EFFICIENT PROPELLERS DESIGNED FOR MACH 0.8 CRUISE
Several advanced aerodynamic and acoustic concepts were investigated in recent wind tunnel tests performed in the NASA-Lewis Research Center 8x6 foot wind tunnel. These concepts included aerodynamically integrated propeller/nacelles, area-ruling, blade sweep, reduced blade thickness, and power (disk) loadings several times higher than conventional designs. Four eight-bladed propeller models were tested to determine aerodynamic performance. Relative noise measurements were made on three of the models at cruise conditions. Three of the models were designed with swept blades and one with straight blades. At the design Mach number of 0.8, power coefficient of 1.7, and advance ratio of 3.06, the straight bladed model had the lowest net efficiency of 75.8 percent. Increasing the sweep to 30 deg improved the performance to near 77 percent. Installation of an area-ruled spinner on a 30 deg sweep model further improved the efficiency to about 78 percent. The model with the highest blade sweep (45 deg) and an area-ruled spinner had the highest net efficiency of 78.7 percent, and at lower power loadings the efficiency exceeded 80 percent. At lower Mach numbers the 30 deg swept model had the highest efficiency. Values near 81 percent were obtained for the design loading at speeds to Mach 0.7. Relative noise measurements indicated that the acoustically designed 45 deg sweep model reduced the near field cruise noise by between 5 and 6 dB.
- Conference paper presented at the Business Aircraft meeting, Wichita, Kansas, 3-6 April 1979. Sponsored by the Society of Automotive Engineers.
Department of the NavyThe Pentagon
Washington, DC United States 20350
- Jeracki, R J
- Mikkelson, D C
- Blaha, B J
- Publication Date: 1979
- Pagination: 24 p.
- TRT Terms: Acoustic measuring instruments; Acoustics; Aerodynamics; Energy conservation; Fuel consumption; Nacelles; Noise control; Propeller blades; Propellers; Sound level; Turboprop aircraft; Wind tunnels
- Uncontrolled Terms: Noise reduction
- Old TRIS Terms: Acoustic measurement; Aerodynamic characteristics; Propeller efficiency; Sweep angle
- Subject Areas: Aviation; Energy; Environment;
- Accession Number: 00197934
- Record Type: Publication
- Source Agency: National Technical Information Service
- Report/Paper Numbers: NASA-TM-79124, E-9960
- Files: TRIS
- Created Date: Sep 15 1979 12:00AM