Open rotor blading
US4969800A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 12, 1989 |
| Grant date | Nov 13, 1990 |
| Priority date | — |
| Expiry date | Jul 12, 2009 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S416/05
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
To reduce the noise levels of open rotor devices rotating at supersonic tip speeds, a combination of blade sweep and aerofoil profile is employed. The sweep of the blade extends through the sonic radius, and in the region of the sonic radius the section comprises a leading edge profile with a rounded nose conforming essentially to the formula EQU T.about.x.sub.L.sup.a L PA1 where T is the blade thickness PA1 x.sub.L is the distance from the front of the leading edge PA1 a.sub.L is an algebraic power greater than 3/4 and less than 1. The leading edge profile extends 2-15% of the aerofoil chord and has a nose radius not greater than 2% of the chord. It can be shown that, by these measures, it is possible to moderate the perceived noise levels from a device such as an aircraft propeller rotating at supersonic tip speeds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.