THE IMPACT OF NOISE REGULATIONS ON PROPELLER DESIGN
The characteristic differences in performance between conventional aerofoil sections and a new section developed to permit an increase in blade loading are presented. The new aerofoil section allows for slower revving propellers without degrading performance or imposing a weight penalty. A range of propellers is outlined to illustrate the tradeoffs among noise, performance, and weight with each type. The first propeller to use the new technology section was a three-blader designed as a cruise propeller (106 in. in diameter, activity factor of 85 per blade, maximum power of 950 hp at 1591 rpm, and 130 lb. in weight). Because of the relatively low activity factor, the static and very low-speed performance increases very slowly once a take-off power of 750 hp is reached. Normally, at this condition the blade would be very near to stall and close to the onset of flutter. However, during testing the propeller was taken up to 1100 hp at 110% rpm, with no significant flutter. This becomes effective at climb-out conditions. Full certification is expected for the propeller; it is vibration free, is quieter than its conventionally designed counterpart, and meets performance goals. A slightly smaller blade can be fitted into the same hub for the faster revving engines with lower powers. Use of the blades in a four-way hub is contemplated and hardware and testing are expected in late summer 1979. For larger diameter applications, a more rugged blade is being developed for fitment into a four-way hub. Current programs sponsored by both the National Aeronautics and Space Administration and the U.K. Department of Industry may permit even further advances towards more efficient and quieter propellers. However, propeller performance in the 250-350 knot speed range is already good, and it will be expensive to extract the last few percent. Better integration between power plant and aircraft will yield bigger improvements than changes to the propeller itself, particularly where reciprocating engines are used.
- Find a library where document is available. Order URL: http://worldcat.org/issn/01487191
- Presented at SAE Business Aircraft Meeting and Exposition, Wichita, Kansas, 3-6 April 1979.
Warrendale, PA United States 15096
- Davis, DGM
- Publication Date: 1979
- Pagination: 12 p.
- TRT Terms: Airfoils; Design; Noise control; Performance; Propellers; Weight
- Subject Areas: Design; Safety and Human Factors;
- Accession Number: 00394072
- Record Type: Publication
- Source Agency: National Highway Traffic Safety Administration
- Report/Paper Numbers: SAE 790593, HS-026 417U
- Files: HSL, USDOT
- Created Date: May 31 1985 12:00AM