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1. WO2020118310 - PROFIL AÉRODYNAMIQUE ROTATIF ET SON PROCÉDÉ DE CONCEPTION

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

[ EN ]

CLAIMS

We claim:

1. An airfoil blade, the blade comprising:

• a first airfoil cross section, the first airfoil cross section defining:

• a chord line defining a chord length L;

• a leading edge, comprising a leading edge radius between 0.002L and 0.05L;

• a trailing edge, comprising a trailing edge thickness between zero and 0.03L;

• a maximum thickness between 0.07L and 0.2L and located between 0.2L and 0.6L along the chord line; and

• a maximum camber between zero and 0.2L and located between 0.2L and 0.7L along the chord line.

2. The airfoil blade of claim 1, wherein:

• the leading edge radius is approximately 0.006L;

• the trailing edge thickness is approximately 0.005L;

• the maximum thickness is approximately 0.12L at the position of approximately 0.4L along the chord line; and

• the maximum camber is approximately 0.024L at the position of approximately 0.44L along the chord line.

3. The airfoil blade of claim 2, the first airfoil cross section as described in Table 1.

4. The airfoil blade of claim 1, the first airfoil cross section as described in Table 2.

5. The airfoil blade of claim 1, wherein the airfoil blade defines a blade length between 1 m and 4 m.

6. The airfoil blade of claim 5, wherein the blade is tapered along the blade length.

7. The airfoil blade of claim 1, wherein the airfoil blade defines a twisting angle along the blade length, the twisting angle between 20 degrees and 50 degrees.

8. The airfoil blade of claim l, further comprising an anhedral blade tip.

9. The airfoil blade of claim 1, wherein the chord length L is between .02 m and 1 m.

10. The airfoil bade of claim 1, wherein a rotor comprises the airfoil blade, wherein the rotor generates less than 80 dBA at a measurement distance of 100 meters when operating in a Reynold’s number range between 50k and 1,000k.

11. A rotor for a tilt -rotor aircraft, the rotor defining a disc plane, the rotor comprising:

• a plurality of airfoil blades, each of the plurality of airfoil blades defines a lift coefficient curve at a Reynold’s number range between 50k - 10,000k comprising:

• a first angle of attack (AoA) range;

• a second AoA range, wherein a lower bound of the second AoA range is greater an upper bound of the first AoA range, the second AoA range spanning a width of greater than 5 degrees angle of attack;

• a semi-critical AoA between the lower bound of the second AoA range and the upper bound of the first AoA range; and

• a maximum coefficient of lift (CL) at a critical AoA greater than an upper bound of the second AoA range; and

• a rotor tilt mechanism, the rotor tilt mechanism configured to transform the rotor between:

• a forward configuration, wherein each of the plurality of airfoil blades operates in the first AoA range and the disc plane is parallel to a pitch-yaw plane of the tilt-rotor aircraft; and

• a hover configuration, wherein each of the plurality airfoil blades operates in the second AoA range and the disc plane intersects the pitch-yaw plane.

12. The rotor of claim 11, further comprising a blade pitching mechanism, wherein in the forward configuration the blade pitching mechanism orients each of the plurality of airfoil blades at a forward AoA within the first AoA range, wherein in the hover configuration the blade pitching mechanism orients each of the plurality of airfoil blades at a hover AoA within the second AoA range.

13. The rotor of claim 11, wherein each airfoil further comprises a bump on the upper surface of the airfoil blade, wherein a separation point of each airfoil is located on a trailing portion of the respective bump.

14. The rotor of claim 11, wherein the CL versus AoA curve in the first AoA range defines a first slope (M), wherein the CL versus AoA curve in the second AoA range defines a second slope, wherein the second slope is between zero and .95M.

15. The rotor of claim 14, wherein an absolute value of a rate of change of the second slope is less than .05M per degree.

16. The rotor of claim 14, wherein the CL versus AoA curve comprises a third AoA range between the first AoA range and the second AoA range, wherein the lift coefficient curve defines a third slope in the third AoA range, wherein the third AoA slope is less than half the second slope.

17. The rotor of claim 11, wherein the lift coefficient curve defines a first slope between 0.1 per degree and 0.13 per degree in the first AoA range, wherein the life coefficient curve defines a second slope less than .1 per degree in the second AoA range.

18. The rotor of claim 11, wherein the hover configuration operates below 80 dBA measured from 100 meters.

19. The rotor of claim 11, further comprising a hub, each of the plurality of blades radiating from the hub in the disc plane, wherein an electric motor is integrated into the hub.

20. The rotor of claim 11, the aircraft comprising a second rotor adjacent to the rotor, wherein the second rotor is offset from the disc plane.