Low noise ducted fan

Patent metadata

Field	Value
Publication number	US-11827344-B2
Application number	US-202017116726-A
Country	US
Kind code	B2
Filing date	Dec 9, 2020
Priority date	Dec 9, 2020
Publication date	Nov 28, 2023
Grant date	Nov 28, 2023

Abstract

An exemplary ducted fan includes a duct having a central longitudinal axis, a rotor hub and stator hub extending along the central longitudinal axis, rotor blades extending from the rotor hub, each of the rotor blades operable to rotate about its own pitch-change axis, the pitch-change axes lying in a rotor plane that is generally perpendicular to the central longitudinal axis, each of the rotor blades having a rotor trailing edge and a rotor chord length, stators extending from the stator hub to an interior surface of the duct, each of the stators having a stator leading edge and a stator thickness, and a first separation between the rotor plane and the stator leading edge of not less than approximately 1.5 times the stator thickness.

First claim

What is claimed is:

1. A ducted fan comprising:
a duct having a central longitudinal axis;
a rotor hub and a stator hub extending along the central longitudinal axis;
a plurality of rotor blades extending from the rotor hub, each of the plurality of rotor blades operable to rotate about a respective pitch-change axis of the rotor hub, the pitch-change axes lying in a rotor plane that is substantially perpendicular to the central longitudinal axis, each of the rotor blades having a rotor trailing edge and a rotor chord length; and
a plurality of stators extending from the stator hub to an interior surface of the duct, each of the plurality of stators having a stator leading edge and a stator thickness;
wherein a first separation between the rotor plane and the stator leading edge is 1.5-2.7 times the stator thickness;
wherein a second separation between the rotor trailing edge and the stator leading edge is not less than the rotor chord length.

2. The ducted fan of claim 1 , wherein the first separation is substantially 1.5 times the stator thickness.

3. The ducted fan of claim 1 , wherein a number of the rotor blades and the stators is unequal.

4. The ducted fan of claim 1 , wherein a number of the rotor blades is greater than a number of the stators.

5. The ducted fan of claim 1 , wherein the stator leading edge is inclined toward the rotor plane extending from the stator hub to the interior surface of the duct.

6. The ducted fan of claim 1 , wherein the rotor trailing edge is inclined toward the rotor plane extending from the rotor hub toward the interior surface of the duct.

7. The ducted fan of claim 1 , wherein:
the stator leading edge is inclined toward the rotor plane extending from the stator hub to the interior surface of the duct; and
the rotor trailing edge is inclined toward the rotor plane extending from the rotor hub toward the interior surface of the duct.

8. The ducted fan of claim 1 , wherein the stator leading edge is inclined toward the rotor plane extending from the stator hub to the interior surface of the duct; and
the rotor trailing edge is inclined toward the rotor plane from the rotor hub toward the interior surface of the duct.

9. An aircraft comprising:
a fuselage having a forward portion and an aft portion; and
a tiltable ducted fan comprising:
a duct having a central longitudinal axis;
a rotor hub and a stator hub extending along the central longitudinal axis;

a plurality of rotor blades extending from the rotor hub, each of the plurality of rotor blades operable to rotate about a respective pitch-change axis of the rotor hub, the pitch-change axes lying in a rotor plane that is generally perpendicular to the central longitudinal axis, each of the plurality of rotor blades having a rotor trailing edge and a rotor chord length; and
a plurality of stators extending from the stator hub to an interior surface of the duct, each of the a plurality of stators having a stator leading edge and a stator thickness;
wherein a first separation between the rotor plane and the stator leading edge is 1.5-2.7 times the stator thickness;
wherein a second separation between the rotor trailing edge and the stator leading edge is not less than the rotor chord length.

10. The aircraft of claim 9 , wherein the stator leading edge is inclined toward the rotor plane extending from the stator hub to the interior surface of the duct.

Assignees

• Bell Textron Inc
• Textron Innovations Inc

Inventors

• Truong Alexander Dang Quang
• Schroeder Karl
• Ryan Michael John

Classifications

• B64D27/24

  using steam or spring force (jet aircraft B64D27/16) · CPC title

• B64C11/001 Primary

  Shrouded propellers · CPC title

• B64U10/20

  Vertical take-off and landing [VTOL] aircraft (flying platforms B64U10/13; helicopters B64U10/17) · CPC title

• B64U30/297

  Tilting rotors · CPC title

• B64U50/14

  ducted or shrouded · CPC title