Office National D'etudes Et De Recherche Aerospatiales

Office National D'etudes Et De Recherches Aerospatiales

Jean-Marc Bousquet

Alain Faubert

Jean-Jacques Thibert

Georges Vingut

The invention provides improvements to aerial propellers, particularly for aircraft propulsive units, wherein the cowling of the propeller is defined by a meridian line having: at its origin (B) a maximum curvature greater than 15; then a curvature decreasing rapidly from the maximum value to a value of 7; then a curvature decreasing linearly from the value 7 to a value of 0; than a curvature decreasing more slowly from the value 0 to a minimum value between -3 and -5; then a curvature increasing rapidly from the minimum value to a value of 0.

Aerial propellers more especially for aircraft propulsive units

The mean line (F) of each blade (1) is formed by a flat continuous curve contained in a plane OZ-OY.sub.o forming with the plane of rotation of the propeller an angle .phi..sub.o between 35.degree. and 55.degree. and preferably between 40.degree. and 50.degree., said curve having a first part of negative Y.sub.o and positive Z coordinates, and a second part of positive Y.sub.o and positive Z coordinates, the coordinate point Y.sub.o =0 being situated between the values of Z included between 0.75 and 0.85 R (R designating the radius of the propeller), the tangent to this curve has its end corresponding to the end of the blade forming with the axis Oz an angle  between 30.degree. and 50.degree. and preferably between 35.degree. and 45.degree..

Aerial propellors more especially for aircraft propulsive units

The external part at least of a propeller blade, having a maximum relative thickness between about 2 and 6%, has a profile whose thickness variation law along the chord comprises a first zone (I) going from the leading edge to about 8% of the length of the chord in which the curvature decreases rapidly, from a maximum value at the leading edge, followed by a second zone (II) extending between about 8% of the chord and midships in which the curvature decreases linearly. In a third zone, extending from midships to 75 to 85% of the chord, the curvature is substantially constant. A fourth zone (IV), extending from the end of the third zone (typically at 80% of the chord) to the trailing edge, comprises a curvature inversion.

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Paris, France

Jean-Marc Bousquet