ULISES A PEREZ
Physician at 4, Miami, FL

2004012, Jul 1, 2004

Dec 30, 2002

10/330225

Gecheng Zha - Coral Gables FL, US
Craig Paxton - Miami FL, US
Peter Gryn - Miramar FL, US
Ulises Perez - Miami FL, US
Erisa Hines - Wheaton MO, US

F03B003/12

416/22300R

A high efficiency forward swept airplane propeller includes a constant leading edge forward swept angle from the root to the tip. The forward sweep is created by leaning the blade leading edge tangentially toward the rotating direction on the rotating plane. The leading edge projection on the axial-radial plane is a straight line with constant axial position from the blade root to the tip. Alternate embodiments of the projection of the leading edge on the tangential rotating plane include: a propeller blade with a leading edge shape that has a smaller forward sweep angle (including 0 degree) in the inner portion of the blade and a larger forward sweep angle in the outer portion; a propeller blade that has a negative leading edge aft ward sweep angle in the inner portion of the blade and a positive forward sweep angle in the outer portion. Alternate embodiment of the leading edge shape projection on the axial-radial plane include a shape which is not a constant line, but at any radial position, the maximum leading edge axial deviation from the root axial position is less than the blade airfoil chord length at that radial position. Compared to the radial blade or backward swept blade, the mechanism that causes the forward swept blade to have a better performance is that the tip pulls more mass flow and has higher flow kinetic energy in the tip region, which suppresses the tip vortex. The effective aspect ratio of the blade is larger and the induced drag and downwash are smaller. The wind tunnel tests and the simulations using 3D computational fluid dynamics software indicated that the forward swept propeller blade of this invention significantly improves the efficiency and stall margin compared to the conventional radial blade.