Airfoil profile for an aircraft and aerodynamic surfaces using said airfoil profile
AssigneeAirbus Operations GmbH
InventorMihai Ioan Zecheru
Life of this patent
Estimating the term…
Abstract
An airfoil profile for an aircraft, such as an unmanned aerial system. The airfoil profile includes a leading edge portion and a trailing edge portion that are spaced apart along a chordwise direction, an airfoil centroid; and an upper airfoil surface and a lower airfoil surface. The airfoil surfaces are shaped such that the pressure center of the lifting force is arranged at the same chord location as the airfoil centroid or closer to the trailing edge portion along the chordwise direction than the airfoil centroid. With this, a pitch-down momentum is generated that urges the leading edge portion towards a lower angle of attack.
Claims17
A propeller blade for an aircraft comprising an airfoil profile, the airfoil profile being configured for reducing a noise level, the airfoil profile comprising:
- a leading edge portion and a trailing edge portion that are spaced apart along a chordwise direction;
- an elastic axis that is arranged from 40% to 60% of a chord length along the chordwise direction;
- and
- an upper airfoil surface and a lower airfoil surface that are shaped so as to generate a lifting force in a manner such that a pressure center of the lifting force is arranged at the same chord location as the elastic axis or closer to the trailing edge portion along the chordwise direction than the elastic axis;
- wherein the upper airfoil surface is defined by a first 6th-order polynomial defined by:
- y(x)=a6x6+a5x5+a4x4+a3x3+a2x2+a1x+a0, where:
- a6 is defined by −0.0078t2−0.043t−3.4025;
- a5 is defined by 0.0249t2+0.0917t+10.762;
- a4 is defined by −0.0301t2−0.0608t−12.691;
- a3 is defined by 0.0165t2+0.0272t+6.6256;
- a2 is defined by −0.0041t2−0.0396t−1.6238;
- a1 is defined by 0.0005t2+0.0232t+0.332;
- and
- a0 is defined by 0.0009t+0.0035;
- and wherein the upper airfoil surface lies within a first tolerance band of +/−5% from the first 6th-order polynomial y(x);
- and
- wherein the lower airfoil surface is defined by a second 6th-order polynomial defined by:
- z(x)=b6x6+b5x5+b4x4+b3x3+b2x2+b1x+b0, where:
- b6 is defined by 0.0021t2+0.3834t−2.2564;
- b5 is defined by −0.0068t2−1.1895t+7.0593;
- b4 is defined by 0.0082t2+1.4243t−8.3201;
- b3 is defined by −0.0042t2−0.8427t+4.4385;
- b2 is defined by 0.0006t2+0.2768t−1.2628;
- b1 is defined by −0.0008t4+0.0439t3−0.9162t2+8.3143t−27.838;
- and
- b0 is defined by −0.00008t+0.0017;
- and wherein the lower airfoil surface lies within a second tolerance band of +/−5% from the second 6th-order polynomial z (x);
- where x corresponds to a percentage of the chord length from 0% to 100%, t is a thickness of the airfoil profile inserted into the respective equation in percent, wherein a result of the first and second 6th-order polynomials is a distance from 0 along a vertical direction in percent of the chord length, and wherein the thickness varies from 8% near a tip of the propeller blade to 18% near a root of the propeller blade opposite the tip.
Dependencies are inferred from the claim text.