Accession Number : AD0777895

Title :   DC-9 Noise Retrofit Feasibility. Volume II. Upper Goal Noise, Performance and Cost Evaluation.

Descriptive Note : Final rept. Jan-Sep 73,

Corporate Author : DOUGLAS AIRCRAFT CO LONG BEACH CALIF

Personal Author(s) : Whallon,H. D.

Report Date : DEC 1973

Pagination or Media Count : 159

Abstract : The work described in the report covers the work performed in Phase II of this program. This Upper Goal nacelle configuration study was directed toward noise reduction goals of 4, 4, 5, and 10 EPNdB at the Federal Aviation Regulations (FAR) Part 36 sideline, takeoff, cutback, and approach measurement conditions, respectively. Exhaust system development tests were conducted on an engine static test stand to evaluate the Upper Goal exhaust system. Components of the Upper Goal nacelle were designed and fabricated. The components were ground static tested for effect on engine performance and noise. The initial daisy-with-ejector configuration showed good acoustical results but with unacceptable performance losses, even after a number of modifications. An alternative configuration, using the same test hardware but adjusted to provide quieting by enlarging the nozzle area, essentially met acoustical and performance requirements. Static tests demonstrated predicted inflight noise reductions of 4.7, 4.0, 3.9, and 10.1 EPNdB at the sideline, takeoff, cutback, and approach measurement conditions, respectively, which approximate the FAA Upper Goal values. (Modified author abstract)

Descriptors :   *Passenger aircraft, *Jet engine noise, *Noise reduction, Jet engines, Jet engine nacelles, Experimental design, Exhaust nozzles, Modification, Cost analysis

Subject Categories : Civilian Aircraft
      Acoustics
      Jet and Gas Turbine Engines

Distribution Statement : APPROVED FOR PUBLIC RELEASE