A propeller comprising: a central post coincident with a rotational axis; one or more blades each having a distal end and a proximate end; each of the one or more blades comprising a top portion, a bottom portion, and a side portion, the side portion disposed at or toward the distal end; the top portion and bottom portion of each of the one or more blades connected at the proximate end to and extending radially outward from the central post, and wherein the top portion is located closer to the propeller's front than the bottom portion and the bottom portion is located closer to the propeller's back than the top portion; a gap between the central post connections of the top portion and bottom portion of at least one of the one or more blades wherein air is compressed upon rotation of the propeller; and the one or more blades disposed and configured to pull air inward from the blade's side portion toward the propeller's axis of rotation and from the propeller's front to its back in the longitudinal direction of the rotational axis; wherein at least one pair of blades opposing one another about the rotational axis; wherein the top portion of one of the blades of the pair of blades intersects the central post at a first blade intersection and the bottom portion of the one of the blades intersects the central post at a second blade intersection and the top portion of the other one of the blades of the pair of blades intersects the central post at a third blade intersection and the bottom portion of the other one of the blades intersects the central post at a fourth blade intersection; and characterised in that the angle of the first blade intersection with respect to the rotational axis is different from the angle of the third blade intersection with respect to the rotational axis, and the angle of the second blade intersection with respect to the rotational axis is different from the angle of the fourth blade intersection with respect to the rotational axis; and in that, as measured from a line perpendicular to the longitudinal axis of the propeller, the angle of the second blade intersection is greater than the angle of the first blade intersection and the angle of the fourth blade intersection is greater than the angle of the third blade intersection. a central post coincident with a rotational axis; one or more blades each having a distal end and a proximate end; each of the one or more blades comprising a top portion, a bottom portion, and a side portion, the side portion disposed at or toward the distal end; the top portion and bottom portion of each of the one or more blades connected at the proximate end to and extending radially outward from the central post, and wherein the top portion is located closer to the propeller's front than the bottom portion and the bottom portion is located closer to the propeller's back than the top portion; a gap between the central post connections of the top portion and bottom portion of at least one of the one or more blades wherein air is compressed upon rotation of the propeller; and the one or more blades disposed and configured to pull air inward from the blade's side portion toward the propeller's axis of rotation and from the propeller's front to its back in the longitudinal direction of the rotational axis; wherein at least one pair of blades opposing one another about the rotational axis; wherein the top portion of one of the blades of the pair of blades intersects the central post at a first blade intersection and the bottom portion of the one of the blades intersects the central post at a second blade intersection and the top portion of the other one of the blades of the pair of blades intersects the central post at a third blade intersection and the bottom portion of the other one of the blades intersects the central post at a fourth blade intersection; and characterised in that the angle of the first blade intersection with respect to the rotational axis is different from the angle of the third blade intersection with respect to the rotational axis, and the angle of the second blade intersection with respect to the rotational axis is different from the angle of the fourth blade intersection with respect to the rotational axis; and in that, as measured from a line perpendicular to the longitudinal axis of the propeller, the angle of the second blade intersection is greater than the angle of the first blade intersection and the angle of the fourth blade intersection is greater than the angle of the third blade intersection.