FR2623162A1 - DEVICE FOR CYCLIC VARIATION IN THE GEOMETRY OF BLADES FOR TURNED AIRCRAFT - Google Patents
DEVICE FOR CYCLIC VARIATION IN THE GEOMETRY OF BLADES FOR TURNED AIRCRAFT Download PDFInfo
- Publication number
- FR2623162A1 FR2623162A1 FR8716041A FR8716041A FR2623162A1 FR 2623162 A1 FR2623162 A1 FR 2623162A1 FR 8716041 A FR8716041 A FR 8716041A FR 8716041 A FR8716041 A FR 8716041A FR 2623162 A1 FR2623162 A1 FR 2623162A1
- Authority
- FR
- France
- Prior art keywords
- blade
- bar
- skin
- profile
- twist
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B64—AIRCRAFT; AVIATION; COSMONAUTICS
- B64C—AEROPLANES; HELICOPTERS
- B64C27/00—Rotorcraft; Rotors peculiar thereto
- B64C27/32—Rotors
- B64C27/46—Blades
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Aviation & Aerospace Engineering (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
Description
La présente invention concerne des aéronefs à voilures tournantes et plus particulièrement les hélicoptères équipés d'un rotor qui permet d'améliorer les performances en vitesse, maximale, en charge utile et en consomation. The present invention relates to rotary wing aircraft and more particularly helicopters equipped with a rotor which improves performance in speed, maximum, payload and consumption.
La vitesse d'avancement d'un hélicoptère classique est essentiellement limitée par la dissymétrie des vitesses entre la pale avançante et la pale reculante. The forward speed of a conventional helicopter is essentially limited by the asymmetry of the speeds between the advancing blade and the advancing blade.
Alors que la pale avançante approche une vitesse, où les effets de compressibilité deviennent génants, la vitesse de l'écoulement sur la pale reculante est trés faible et même négative dans une zone proche du moyeu appelée cercle d'inversion.As the advancing blade approaches a speed, where the compressibility effects become annoying, the speed of the flow on the receding blade is very low and even negative in an area close to the hub called the inversion circle.
On compense normalement ce déséquilibre par la commande cyclique de pas, qui permet d'avoir une trés faible incidence sur la pale avançante et une forte incidence sur la pale reculante qui se trouve dans des conditions prochesdu décrochage en extrémité et crée une portance négative dans le cercle d'inversion. This imbalance is normally compensated for by the cyclic pitch control, which makes it possible to have a very low incidence on the advancing blade and a strong incidence on the retreating blade which is in conditions close to the stall at the end and creates a negative lift in the inversion circle.
Le dispositif selon l'invention représenté fig.1 permet de remédier à ce problème en modifiant le vrillage de la pale de façon cyclique, ce qui permet de ne pas avoir d'inversion de portance. The device according to the invention shown in fig.1 overcomes this problem by modifying the twist of the blade cyclically, which allows not to have a reversal of lift.
Chaque pale (1) du rotor est creuse, et souple en torsion. Each rotor blade (1) is hollow, and flexible in torsion.
Une barre (2) rigide en torsion, passe à l'intérieur de chaque pale, une extrémité de la barre est fixée en un point de la pale choisie relativement proche de son extrémité, l'autre extrémité de la barre est articulée sur la ferrure de reprise (4) et comporte une corne de commande (3).A bar (2) rigid in torsion, passes inside each blade, one end of the bar is fixed at a point of the chosen blade relatively close to its end, the other end of the bar is articulated on the fitting of recovery (4) and comprises a control horn (3).
Le systéme de commande de pas comporte deux plateaux cycliques indépendants, l'un permet de commander la corne de commande de pas classique (5), l'autre la corne (3) de la barre (2). The pitch control system has two independent swashplates, one for controlling the conventional pitch control horn (5), the other for the bar (2) horn (3).
En agissant différemment sur les deux plateaux cycliques, on obtient un vrillage de la pale qui peut-être cyclique en vol d'avancement ou constant en vol stationnaire.By acting differently on the two swashplates, one obtains a twist of the blade which may be cyclic in forward flight or constant in hovering.
En combinant le vrillage initial de la pale et le vrillage cyclique on peut optimiser l'incidence et la répartition de la charge sur la pale dans tous les cas de vol. By combining the initial twist of the blade and the cyclic twist, the incidence and distribution of the load on the blade can be optimized in all cases of theft.
La partie de pale qui passe dans le cercle d'inversion devra avoir un profil qui fonctionne correctement dans le sens normal et présente une traînée réduite lorsqu'il est soufflé à l'envers avec une incidence adaptée. The part of the blade which passes through the inversion circle must have a profile which functions correctly in the normal direction and exhibits reduced drag when it is blown backwards with an appropriate incidence.
En extémité de pale le profil travaille à des vitesses qui sont, ou proches de la vitesse du son, ou trés faibles. Il est donc trés difficile d'avoir un bon rendement de la pale dans une aussi grande étendue de vitesse. At the blade tip, the profile works at speeds which are, or close to the speed of sound, or very low. It is therefore very difficult to have a good blade efficiency in such a large speed range.
Les figures 2,3,4 et 5 montrent un dispositif qui permet de modifier la courbure et l'épaisseur du profil pour l'adapter aux conditions d'écoulement qu'il rencontre au cours de la rotation. Figures 2,3,4 and 5 show a device which makes it possible to modify the curvature and the thickness of the profile to adapt it to the flow conditions it encounters during rotation.
L'extrémité de la pale (1) est constituée d'une peau flexible (6) à l'intérieur de laquelle on trouve, un caisson (7) qui est seulement fixé à l'avant de la partie extrados de la peau dans la zone (A) et solidaire du reste de la pale, et une barre rigide en torsion (2) dont une extrémité épouse la forme du bord de fuite et est fixée sous l'extrados dans la zone (B), l'autre extrémité comporte comme dans le cas précédent une corne de commande (3) et est articulée sur la ferrure de reprise de la pale (4). The end of the blade (1) consists of a flexible skin (6) inside which there is a box (7) which is only fixed to the front of the upper surface part of the skin in the zone (A) and integral with the rest of the blade, and a rigid torsion bar (2), one end of which follows the shape of the trailing edge and is fixed under the upper surface in zone (B), the other end comprises as in the previous case a control horn (3) and is articulated on the blade return fitting (4).
La figure 3 représente une section de la peau dans la zone (A) avant l'assemblage, l'extrados est quasiment plat alors que l'intrados a la forme d'un intrados de profil cambré,la flexibilité de la peau n'est pas uniforme autour du profil, ce qui permet de localiser les déformations autour des génératrices C,D et E.FIG. 3 represents a section of the skin in the area (A) before assembly, the upper surface is almost flat while the lower surface has the form of a lower surface with a curved profile, the flexibility of the skin is not not uniform around the profile, which makes it possible to locate the deformations around generatrices C, D and E.
Les deux cotés du bord de fuite sont ensuite assemblés, les zones d'assemblage sont représentées en traits forts sur les figures 3, 4 et 5.The two sides of the trailing edge are then assembled, the assembly zones are shown in strong lines in FIGS. 3, 4 and 5.
Lorsqu'on agit sur la corne (3), on crée un moment de torsicn qui entraine une torsion de la pale et une modification du profil dans la zone (A). When acting on the horn (3), a torsional moment is created which causes the blade to twist and modify the profile in the area (A).
Lorsqu'on applique un moment M-, l'extrados reprend la forme initiale, alors que l'intrados se trouve tendu re long des caissons, on a un profil adapté aux trés grandes vitesses fig.4.When applying a moment M-, the upper surface returns to the initial shape, while the lower surface is stretched along the caissons, we have a profile adapted to very high speeds fig.4.
Lorsqu'on applique un moment M+, on assiste à une flexion de l'extrados alors que l'intrados reprend sa forme initiale, le profil est alors adapté aux basses vitesses et aux fortes incidences, la forme triangulée C,D,E est capable de résister sans féformation importentes aux efforts de pression aérodynamique fig.5.When applying a moment M +, we observe a bending of the upper surface while the lower surface returns to its initial shape, the profile is then adapted to low speeds and high incidences, the triangulated shape C, D, E is capable to resist aerodynamic pressure forces without significant deformation fig.5.
La raideur de chaque élément(caissons,extrados et intrados de la peau) est choisie due façon à obtenir un bon rapport entre la torsion de la pale et la modification du profil, et à éviter les les phénomènes de flottement. les matériaux utilisés doivent avoir une souplesse et une limite en fatigue adaptés aux emplitudes et fréquences élevés des cycles de déformation. The stiffness of each element (boxes, upper and lower surfaces of the skin) is chosen due to obtaining a good relationship between the twist of the blade and the modification of the profile, and to avoid the phenomena of floating. the materials used must have a flexibility and a fatigue limit adapted to the high frequencies and frequencies of the deformation cycles.
Il est impossible de piloter les deux plateaux cycliques manuellement. On aura donc recours aux commandes de vol électriques par l'intermédiaire d'un calculateur qui prendra les ordres de cornmande du pilote, les informations sur les conditions du vol, la dynamique du rotor et optimisera la géométrie de celui-ci dans tous les cas de vol de l'hélicoptère. It is impossible to control the two swashplates manually. We will therefore have recourse to electric flight controls by means of a computer which will take the pilot's orders, information on the flight conditions, the dynamics of the rotor and will optimize the geometry of the latter in all cases. helicopter flight.
Claims (7)
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8716041A FR2623162B1 (en) | 1987-11-12 | 1987-11-12 | DEVICE FOR CYCLIC VARIATION IN THE GEOMETRY OF BLADES FOR AIRCRAFT WITH TURNING WING |
PCT/FR1988/000541 WO1989004276A1 (en) | 1987-11-12 | 1988-11-04 | Device for cyclic variation of the blade geometry of high-speed helicopters |
AU27133/88A AU2713388A (en) | 1987-11-12 | 1988-11-04 | Device for cyclic variation of the blade geometry of high- speed helicopters |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8716041A FR2623162B1 (en) | 1987-11-12 | 1987-11-12 | DEVICE FOR CYCLIC VARIATION IN THE GEOMETRY OF BLADES FOR AIRCRAFT WITH TURNING WING |
Publications (2)
Publication Number | Publication Date |
---|---|
FR2623162A1 true FR2623162A1 (en) | 1989-05-19 |
FR2623162B1 FR2623162B1 (en) | 1990-03-09 |
Family
ID=9356964
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
FR8716041A Expired - Lifetime FR2623162B1 (en) | 1987-11-12 | 1987-11-12 | DEVICE FOR CYCLIC VARIATION IN THE GEOMETRY OF BLADES FOR AIRCRAFT WITH TURNING WING |
Country Status (3)
Country | Link |
---|---|
AU (1) | AU2713388A (en) |
FR (1) | FR2623162B1 (en) |
WO (1) | WO1989004276A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB2464678B (en) * | 2008-10-21 | 2013-04-10 | David Hostettler Wain | Dual swash plates |
US9487291B2 (en) * | 2012-12-05 | 2016-11-08 | The Boeing Company | Apparatus, system, and method for pitching and twisting a blade of a rotorcraft |
US9457889B2 (en) * | 2013-09-24 | 2016-10-04 | The Boeing Company | Rotorcraft rotor including primary pitch horns and secondary horns |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1047568A (en) * | 1963-10-09 | 1966-11-09 | Westland Aircraft Ltd | Improvements in or relating to aircraft rotors |
FR2395187A2 (en) * | 1977-06-24 | 1979-01-19 | Onera (Off Nat Aerospatiale) | AERODYNAMIC PROPULSION UNIT WITH GEAR BLADES |
-
1987
- 1987-11-12 FR FR8716041A patent/FR2623162B1/en not_active Expired - Lifetime
-
1988
- 1988-11-04 AU AU27133/88A patent/AU2713388A/en not_active Abandoned
- 1988-11-04 WO PCT/FR1988/000541 patent/WO1989004276A1/en unknown
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1047568A (en) * | 1963-10-09 | 1966-11-09 | Westland Aircraft Ltd | Improvements in or relating to aircraft rotors |
FR2395187A2 (en) * | 1977-06-24 | 1979-01-19 | Onera (Off Nat Aerospatiale) | AERODYNAMIC PROPULSION UNIT WITH GEAR BLADES |
Also Published As
Publication number | Publication date |
---|---|
WO1989004276A1 (en) | 1989-05-18 |
AU2713388A (en) | 1989-06-01 |
FR2623162B1 (en) | 1990-03-09 |
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