Propeller blade

A propeller, comprising:

• a hub having a rotational axis;
• and
• a plurality of blades extending radially outward from the hub, each blade of the plurality of blades comprising:
• a body, comprising:
• a base at an end close to the hub;
• an upper end at an end further away from the hub;
• a front surface, extending between a leading end and a trailing end of the body;
• and
• a back surface, the back surface being a high positive pressure surface of the body,
• wherein:
• the trailing end is a curved surface;
• the leading end is a sham edge such that it is an abrupt turn without a curve;
• the front surface is continuously flat in a single plane from the leading end to the trailing end, such that the back surface and the front surface form a straight line at their junction at the leading end;
• the back surface comprises a first back surface and a second back surface;
• the first back surface is a continuously flat surface from the leading end to a back surface curve;
• the second back surface is a continuously flat surface from the back surface curve to the trailing end;
• a thickness of the blade, defined as the distance between the front surface and the back surface, continuously increases from the leading end to the back surface curve at a first rate;
• the thickness of the blade continuously increases from the back surface curve to the trailing end at a second rate less than the first rate;
• the upper end has a first width between the leading end and the trailing end;
• the base has a second width between the leading end and the trailing end;
• and
• the first width is greater than the second width;
• and
• a tippet extending along the upper end of the body between the leading end and the trailing end, the tippet curving in a direction generally away from the front surface and overhanging the back surface, the tippet forming a channel with a radius of curvature that varies between the leading end and trailing end of the body;
• wherein the tippet is shaped to draw fluid inward toward the hub from a radial inlet flow that enters the channel along a top end of the tippet as well as along the leading end of the body.

A propeller, comprising:

• a hub having a rotational axis;
• and
• a plurality of blades extending radially outward from the hub, each blade of the plurality of blades comprising:
• a body having a base coupled to the hub and extending radially outward from the hub to an upper end, the body comprising:
• a base;
• an upper end;
• a front surface extending between a leading end and a trailing end of the body;
• and
• a back surface opposite the front surface, the back surface of the body being a high positive pressure surface of the body,
• wherein:
• the trailing end is a curved surface;
• the leading end is a sharp edge such that it is an abrupt turn without a curve;
• the front surface is continuously flat in a single plane from the leading end to the trailing end, such that the back surface and the front surface form a straight line at their junction at the leading end;
• the back surface comprises a first back surface and a second back surface;
• the first back surface is a continuously flat surface from the leading end to a back surface curve;
• the second back surface is a continuously flat surface from the back surface curve to the trailing end;
• a thickness of the blade, defined as the distance between the front surface and the back surface, continuously increases from the leading end to the back surface curve at a first rate;
• the thickness of the blade continuously increases from the back surface curve to the trailing end at a second rate less than the first rate;
• the upper end has a first width between the leading end and the trailing end;
• the base has a second width between the leading end and the trailing end;
• the first width is greater than the second width;
• and
• a tippet comprising a front surface and an opposing back surface respectively extending radially outward from the front surface and the back surface of the body at the upper end of the body to a top end and between a leading end and a trailing end, the tippet curving generally away from the front surface of the body and toward the back surface of the body as the tippet extends radially outward, so that the back surface of the tippet overhangs the back surface of the body so as to form a channel extending between the leading end and the trailing end of the tippet, the channel having a curve extending between the top end of the tippet and the upper end of the body along a lateral length of the tippet, a radius of curvature of the curve being varied along the lateral length of the tippet, the top end of the tippet forming a second leading edge between the leading end and the trailing end of the tippet.