Acoustic Flight Test of the Piper Lance,
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 certification test presently required. It was initially assumed that equivalency could be established between the takeoff and level flyrover procedures via adjustment equations involving propeller helical-tip Mach number and noise propagation distance to account for differences in airspeed and altitude respectively. However, it was found that the propeller helical-tip March number adjustment equations 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 c 3 to 4 dB higher than the level flyover noise levels. This effect is believed to result from unsteady propeller blade loading when the aircraft is in a pitch-up position during a takeoff/climbout as opposed to level flight. The test aircraft was a Piper Cherokee Lance equipped with a two-blade constant speed propeller.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1986
- Accession Number
- ADA175718
Entities
People
- K. E. Jones
Organizations
- Federal Aviation Administration