Method for manufacturing propulsion unit having rim foil, and propulsion unit and flying vehicle manufactured by the same
A method for manufacturing a propulsion unit having a rim foil, which significantly reduces drag during forward flight while protecting a rotor blade from surrounding obstacles, the method including a plate member formation step in which an airfoil-type plate member is formed to have an outline forming an airfoil shape in side view, a rim foil formation step in which a through-hole is formed in the airfoil type plate member to form a rim foil member having an outline forming at least a portion of an airfoil shape in side view, and a rotor blade installation step in which a rotor blade is installed in the through-hole.
1. A method for manufacturing a propulsion unit having a rim foil, comprising:
a plate member formation step in which an airfoil-type plate member is formed to have an outline forming an airfoil shape in side view, wherein the airfoil shape includes an upper surface which is formed curving upwardly and a lower surface which is formed curving upwardly;
a rim foil formation step in which a through-hole is formed in the airfoil type plate member to form a rim foil member having an outline forming at least a portion of the airfoil shape in side view; and
a rotor blade installation step in which a rotor blade is installed in the through-hole, wherein
the airfoil-type plate member is continuously changed in cross-sectional thickness parallel to a forward direction, and decreases in an airfoil-shaped cross-section thickness from a center line in the forward direction toward both ends in a lateral direction perpendicular to the forward direction, and
the rim foil member has a central area in which the rotor blade is disposed and a side area lying on both lateral sides of the central area, wherein the side area of the rim foil member has the airfoil shape corresponding to the airfoil-shaped cross-section of the airfoil-type plate member in cross-section parallel to the forward direction.
2. The method according to claim 1 , wherein a projection area of the airfoil-type plate member in plain view covers a projection area of the rotor blade.
3. The method according to claim 1 , wherein:
at least some cross-sections of the rim foil member comprise a leading cross-sectional region having a leading edge at a front end thereof and a trailing cross-sectional region having a trailing edge at a rear end thereof; and
an empty cross-sectional region, which is a portion of the through-hole in which the rotor blade is installed, is placed between the leading cross-sectional region and the trailing cross-sectional region.
4. The method according to claim 1 , wherein, in the plate member formation step, the airfoil-shaped cross-section of the airfoil-type plate member is set to have a zero-lift angle of attack of −9 degrees to −5 degrees.
5. The method according to claim 1 , wherein, in the rim foil formation step, the through-hole is formed in a direction perpendicular to a chord line of an airfoil-shaped cross-section of the rim foil member.
6. The method according to claim 1 , wherein, in the rotor blade installation step, an axis of rotation of the rotor blade is placed perpendicular to a chord line of an airfoil-shaped cross-section of the rim foil member such that the chord line is parallel to the rotor blade.
7. A propulsion unit manufactured by the method according to claim 1 .
8. A flying vehicle comprising:
a body; and
the propulsion unit according to claim 7 , the propulsion unit allowing the body to fly.
9. The flying vehicle according to claim 8 , further comprising:
a fixed wing disposed between the body and the rim foil member,
wherein the rim foil member and the fixed wing have the same airfoil-shaped cross section.
10. The flying vehicle according to claim 8 , further comprising:
a passenger capsule coupled to the body, the passenger capsule having a forward thrust rotor blade producing forward thrust.