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Tone noise of three supersonic helical tip speed propellers in a wind tunnel
| Content Provider | NASA Technical Reports Server (NTRS) |
|---|---|
| Author | Dittmar, J. H. Blaha, B. J. Jeracki, R. J. |
| Copyright Year | 1979 |
| Description | Three supersonic helical tip speed propellers were tested in the NASA Lewis 8- by 6-foot wind tunnel. This is a perforated-wall wind tunnel but it does not have acoustic damping material on its walls. The propellers were tested at tunnel through flow Mach numbers of 0.6, 0.7, 0.75, 0.8, and 0.85 with different rotational speeds and blade setting angles. The three propellers, which had approximately the same aerodynamic performance, incorporated different plan forms and different amounts of sweep and yielded different near field noise levels. The acoustically designed propeller had 45 deg of tip sweep and was significantly quieter at M = 0.8 cruise than the straight bladed propeller. The intermediate 30 deg tip sweep propeller, which was swept for aerodynamic purposes, exhibited noise that was between the other two propellers. Noise trends with varying helical tip Mach number and blade loading were also observed. |
| File Size | 2255311 |
| Page Count | 64 |
| File Format | |
| Alternate Webpage(s) | http://archive.org/details/NASA_NTRS_Archive_19790017669 |
| Archival Resource Key | ark:/13960/t3wt3gq47 |
| Language | English |
| Publisher Date | 1979-01-01 |
| Access Restriction | Open |
| Subject Keyword | Acoustics Propeller Blades Harmonics Blade Tips Acoustic Measurement Propellers Supersonic Speed Noise Reduction Noise Intensity Sweep Effect Helical Flow Wind Tunnel Tests Ntrs Nasa Technical Reports Server (ntrs) Nasa Technical Reports Server Aerodynamics Aircraft Aerospace Engineering Aerospace Aeronautic Space Science |
| Content Type | Text |
| Resource Type | Article |
