IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0381934
(1982-05-26)
|
우선권정보 |
FR-0011232 (1981-06-05) |
발명자
/ 주소 |
- Philippe, Jean-Jacques
- Lyothier, Robert M.
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출원인 / 주소 |
- Office Nationale d'Etudes et de Recherches Aerospatiales, Societe Nationale Industrielle Aerospatiale
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대리인 / 주소 |
Merriam, Marshall & Bicknell
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인용정보 |
피인용 횟수 :
12 인용 특허 :
3 |
초록
▼
The invention relates to a blade end for rotary wing of an aircraft, whose span is between 5 and 15% of the span of said blade. According to the invention, this blade end is charaterized in that, between points A and B', there is a stagger which, measured parallel to the span of the blade, is betwee
The invention relates to a blade end for rotary wing of an aircraft, whose span is between 5 and 15% of the span of said blade. According to the invention, this blade end is charaterized in that, between points A and B', there is a stagger which, measured parallel to the span of the blade, is between 5 and 25% of the chord of the profile of the blade adjacent said blade end and in that the leading edge line of said blade end is curvilinear and such that its angle of sweep φ varies progressively and continuously from a low value φ o near the blade, of between 0° and 30°, up to a high value φ E towards the outside of the blade, of between 60° and 90°. The invention leads to increased performances and to a reduction in the noise level of rotary wings.
대표청구항
▼
1. A helicopter rotor blade of selected span having a leading edge, a trailing edge, a chord dimension extending between said edges, as inboard blade section having an inner end adapted to be attached to a hub for rotation therewith about an axis, and an outboard tip section at the outer end of said
1. A helicopter rotor blade of selected span having a leading edge, a trailing edge, a chord dimension extending between said edges, as inboard blade section having an inner end adapted to be attached to a hub for rotation therewith about an axis, and an outboard tip section at the outer end of said inboard blade section, said tip section having a span which is 5-15% of the span of said blade, and a leading edge and a trailing edge which form extensions of the leading edge and trailing edge respectively of said inboard section, said tip section having a maximum chord which is not larger than the chord of the outer end of said inboard blade section adjacent said tip section, said tip section being tapered so that its chord diminishes towards its outboard end, the leading edge of said tip section being swept rearwardly from a first point of juncture with the leading edge of said inboard blade section to a terminal point which is disposed rearwardly of a line of span midway between the leading and trailing edges of said inboard blade section, the leading edge of said tip section being curvilinear and having a sweep angle φ which varies progressively and continuously from a value of 0°-30° at said first point of juncture to a value of 60°-90° at said terminal point, the trailing edge of said tip section including a first inboard portion which forms a colinear extension of the trailing edge of said inboard blade section and a second outboard portion which is swept rearwardly relative to the trailing edge of said inboard section, said first and second portions meeting at a second point of juncture which is more remote from said axis of rotation than is said first point of juncture, the distance between said first and said second points of juncture, measured along a line parallel to the span of said blade, being 5-15% of the chord of the outboard end of said inboard blade section. 2. A rotor blade in accordance with claim 1, wherein said angle of sweep φ varies at least approximately linearly over the major portion of the span of said tip section. 3. A rotor blade in accordance with claim 1, wherein said sweep angle φ, plotted as a function of the span of said tip section has a derivative which is monotonic and decreasing in a first inboard portion of said tip section adjacent the outboard end of said inboard blade section, isotonic and increasing in an outboard portion of said tip section adjacent its outboard end, and substantially constant in a central portion interconnecting said inboard and outboard portions. 4. A rotor blade in accordance with claim 1, in which the second outboard portion of the trailing edge of aid tip section is rectilinear. 5. A rotor blade in accordance with claim 1, wherein said tip section comprises an outer profile at the outboard end of said tip section and an inner profile adjacent the outer end of said inboard blade section, said profiles being parallel and orthogonal to the span of the blade, the chord of said inner profile being larger than that of said outer profile, the outer profile being displaced rearwardly with respect to said inner profile, the front ends of the chords of said profiles being joined by said curvilinear leading edge of said tip section, the rear ends of said chords being joined by a rectilinear trailing edge having an inboard section colinear with the trailing edge of said inboard blade section and a rearwardly swept rectilinear outboard portion. 6. A rotor blade in accordance with claim 5, wherein the span E of said tip section, the chord e of said outer profile, the distance m from the rear point of said outer profile to the leading edge line of the inboard blade section, the distance l from the front point of said outer profile to the leading edge line of the inboard blade section 1, and the distance d from the rear point of said outer profile to the trailing edge line of the inboard blade section are related as follows: ##EQU##0.3C≤c≤0.7C ##EQU##0.5C≤E≤1.5C ##EQU##0.5C≤l≤C ##EQU##1.1C≤m≤1.5C ##EQU##0.1C≤d≤0.5C. 7. A rotor blade in accordance with claim 6, wherein ##EQU##0.7C≤E≤1.1C. 8. A rotor blade in accordance with claim 1, wherein said angle of sweep φ has a value of 0°-15° at said first point of juncture and a value of 70°-85° at said terminal point. 9. A rotor blade in accordance with claim 1, wherein said tip section has a twist resulting from rotation of the chord of its successive profiles about a point located on each said chord at a distance equal to 25±5% of the length of said chord from its leading edge, the locus of points about which said rotations are effected being located in a plane defined by the chord of the inner end of said inboard blade portion having zero twist and an axis about which said inboard blade section is twisted. 10. A rotor blade in accordance with claim 9, wherein said tip section is twisted at an angle which varies linearly along the span of said tip section.
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