	US 12,264,619 B2
	Unducted propulsion system
Syed Arif Khalid, West Chester, OH (US); Daniel L. Tweedt, West Chester, OH (US); and David B. Riddle, Cincinnati, OH (US)
Assigned to General Electric Company, Evendale, OH (US)
Filed by General Electric Company, Schenectady, NY (US)
Filed on Feb. 6, 2023, as Appl. No. 18/164,951.
Application 18/164,951 is a continuation of application No. 17/503,184, filed on Oct. 15, 2021, granted, now 11,572,827.
Prior Publication US 2024/0018900 A1, Jan. 18, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. F02C 3/067 (2006.01); F02C 6/20 (2006.01)

CPC F02C 3/067 (2013.01) [F02C 6/206 (2013.01)]

23 Claims

1. An unducted propulsion system for an aircraft configured for high subsonic cruise comprising:

an axis of rotation;

a forward blade assembly comprised of a plurality of forward blades;

an aft blade assembly comprised of a plurality of aft blades;

a forward housing;

an aft housing;

wherein each forward blade comprises a forward blade root proximal to the axis of rotation and a forward blade tip distal from the axis of rotation;

wherein each aft blade comprises an aft blade root proximal to the axis of rotation and an aft blade tip distal from the axis of rotation;

wherein a flowpath curve corresponds to an intersection of an external surface of the aft housing with a plane containing the axis of rotation and an aft-most point of the aft blade root;

wherein for the flowpath curve, an axial direction, z, is parallel to the axis of rotation and radius, r, is distance from the axis of rotation;

wherein a bulge location with radius r_bon the flowpath curve is found by proceeding aft from the aft-most point on the aft blade root to where a first radius reaches a maximum;

wherein a local minimum with radius r_hon the flowpath curve is found by proceeding forward from the bulge location to a nearest point where a second radius stops decreasing within an axial extent of the aft blade root; and

wherein ratio r_b/r_h>1.081;

wherein ratio r_b/r_h<1.424; and

wherein the forward blade assembly and the forward housing rotate about the axis of rotation, and wherein the aft blade assembly and the aft housing are stationary when the unducted propulsion system is in operation.