| Title | Acoustic flight test of the Piper Lance |
|---|---|
| Record ID | 47913 |
| Personal Name Creator |
Jones, K. E. |
| Source | 106p. in various pagings |
| Corporate Creator | United States. Department of Transportation. Federal Aviation Administration. Office of Environment and Energy |
| Corporate Contributor |
John A. Volpe National Transportation Systems Center (U.S.). Acoustics Facility |
| Publisher | United States. Department of Transportation. Federal Aviation Administration. Office of Environment and Energy |
| Publication Date | 19861200 |
| Language | English |
| Abstract | Research is being conducted to refine current noise regulation of propeller-driven small airplanes. Studies are examining the prospect of a substituting a takeoff procedure of equal stringency for the level flyover certification test presently required. It was initially assumed that equivalency could be established between the takeoff and level flyover procedures via adjustment equations involving propeller helical-tip Mach number and noise propagation distance to account for differences in airspeed and altitude repsectively. However, as test results became available, it was found that the propeller helical-tip Mach number adjustment equation did not adequately account for the measured noise level differences between the takeoff and level flyover procedures. After applying the adjustment equations, the takeoff noise levels were 3 to 4 decibels higher than the level flyover noise levels. The effect is believed to result form unsteady propeller blade loading when the aircraft is in a pitch-up position during a takeoff/climbout as opposted to level flight. The test aircraft was a Piper Cherokee Lance (PA-32R-300) equipped with a two-blade constant speed propeller. The objective required a series of flights ranging from level flyover to a takeoff/climbout performed Vx (speed for best angle climb). Noise level versus propeller inflow angle was addressed by a series-to-series variation of aircraft speed at constant power and RPM. Since airspeed is a component of the helical tip Mach number (Mb), and given the generally strong influence of M on noise levels, additional series of overflights were necessary to empirically relate M to the noise level actually produced by the Lance. The M issue was addressed through a series-to-series variation of propeller RPM at constant power and airspeed. |
| Rosap ID | dot:10024 |
| Rosap URL | https://rosap.ntl.bts.gov/view/dot/10024 |
| TRT Terms | Aircraft noise; Small aircraft; Propeller blades; Cavitation noise; Airspeed; Takeoff; Flight tests |
| General Subjects | Acoustic measurement; Propeller blades; Propeller noise; Overflights |
| Classification | AGR - IMPACTS - Environment; NTL - AVIATION - Aviation Energy and Environment; NTL - ENERGY AND ENVIRONMENT - Aviation Energy and Environment |
| Geographical Coverage |
United States |
| TRIS Online Accession No |
1496730 |
| Report Number | DOT/FAA/EE-86/9 |
| Availability | Volpe National Transportation Systems Center, Technical Reference Center |
| Resource type | Tech Report |
| URL | https://ntlrepository.blob.core.windows.net/lib/47000/47900/47913/Piper_Lance.pdf |
| Format | |
| Database | NTL Digital Repository |