Patent ID: 11913470
Assignee: JAPAN AEROSPACE EXPLORATION AGENCY
Field: Transport (Mechanical engineering)
Classification: CPC F  B  H | IPC B  F

Claim 0:
1. A ducted fan, comprising:
a duct including a round-shaped lip; and
a propeller including a blade comprising a root and a tip opposite from the root, wherein the tip is adjacent to an inner wall of the duct, wherein a chord length of the blade gradually decreases from the root toward the tip until a tip vicinity portion and then increases from the tip vicinity portion to the tip such that: an axial velocity of flow in the duct increases from the root of the blade as it gets closer to the tip of the blade; and the axial velocity of flow is largest at the tip of the blade,
wherein a position of the tip vicinity portion at which the chord length increases is within a distance equivalent to 15% of a radius of the blade from the tip.