High performance outboard section for rotor blades
US8128376B2 · kind B2 · utility
Inventor
Key dates
| Filing date | Aug 15, 2006 |
| Grant date | Mar 6, 2012 |
| Priority date | — |
| Expiry date | Apr 7, 2030 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB64C27/467
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
Blades for rotorcraft are designed and/or implemented with rotor blades having a swept portion that occupies at least 20-40% of a length of the blade. Forward and aft sweeps are contemplated, with up to 20° or more of sweep. The swept portion preferably has a thickness ration of at least 10-20% at R80, and can have a tapered planform with a relatively outboard section having a smaller chord than a relatively inboard section. Contemplated design methods include optimizing or otherwise designing the rotor blade planform and lift distribution along the blade for efficiency in various flight conditions without taking into account the detrimental effects of high Mach numbers, and then using sweep angle, airfoil thickness and transonic airfoil shaping to maintain the lift distribution, low drag and low noise level at real Mach numbers at the various blade stations at the various flight conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.