Angle of attack sensor with rotatable airfoil

Patent metadata

Field	Value
Publication number	US-10725065-B2
Application number	US-201615350774-A
Country	US
Kind code	B2
Filing date	Nov 14, 2016
Priority date	Nov 14, 2016
Publication date	Jul 28, 2020
Grant date	Jul 28, 2020

Abstract

An angle of attack sensor includes a vane that is freely rotatable to align with a direction of an oncoming airflow over the vane. The airfoil includes a root proximate a vane hub that connects to a rotatable shaft, a tip opposite the root, a leading edge, a trailing edge opposite the leading edge, a first lateral face, a second lateral face, and a heating element disposed within the airfoil between the first and second lateral faces proximate the leading edge. The first lateral face extends from the leading edge to the trailing edge. The second lateral face is opposite the first lateral face and extends from the leading edge to the trailing edge. The first and second lateral faces are symmetric about a chord of the airfoil and each have an outer surface profile that is nonlinear and geometrically convex from the leading edge to the trailing edge.

First claim

The invention claimed is:

1. An angle of attack sensor comprising:
a housing;
a rotatable shaft disposed within the housing;
a rotary position sensor, disposed within the housing, that senses rotational position of the rotatable shaft; and
a vane that is connected to the rotatable shaft and configured to freely rotate to align with a direction of an oncoming airflow over the vane, the vane comprising:
a vane hub connected to the rotatable shaft; and
an airfoil extending from the vane hub and comprising:
a root proximate the vane hub;
a tip opposite the root;
a leading edge extending from the root to the tip;
a trailing edge opposite the leading edge and extending from the root to the tip;
a first lateral face extending from the leading edge to the trailing edge;
a second lateral face, opposite the first lateral face and extending from the leading edge to the trailing edge,
wherein the first and second lateral faces are symmetric about a chord of the airfoil that extends between the leading edge and the trailing edge of the airfoil, wherein each of the first and second lateral faces have an outer surface profile that is nonlinear and geometrically convex from the leading edge to the trailing edge, and
a heating element disposed within the airfoil between the first and second lateral faces and having a forward end and a trailing end, a distance between the forward end and the trailing end being less than twenty-five percent of a length of the chord and the forward end of the heating element being proximate the leading edge of the airfoil;
and wherein a distance from the leading edge of the airfoil to the trailing end of the heating element extending in a direction along the chord of the airfoil is less than twenty-five percent of the length of the chord and a distance between the leading edge of the airfoil and the forward end of the heating element is less than ten percent the length of the chord such that the heating element is located closer to the leading edge than the trailing edge and is located only within a first quarter of the chord where a majority of heat transfer from the airfoil to an oncoming airflow occurs.

2. The angle of attack sensor of claim 1 ,
wherein each of the first and second lateral faces are defined by a continuous polynomial function of third order or greater.

3. The angle of attack sensor of claim 2 ,
wherein the polynomial function provides as output a half-thickness of the airfoil as measured from the chord to each of the first and second lateral faces as a function of an input ratio of a given location of the chord to a length of the chord.

4. The angle of attack sensor of claim 2 ,
wherein the polynomial is:

y
t

=

5
⁢

tc
[

0.2969
⁢

x
c

+

(

-
0.1260

)

⁢

(

x
c

)

+

(

-
0.3516

)

⁢

(

x
c

)

2

+

0.2843
⁢

(

x
c

)

3

+

(

-
0.1015

)

⁢

(

x
c

)

4

]

;

wherein y t is a half-thickness of the airfoil as measured from the chord to each of the first and second lateral faces;
wherein c is the length of the chord;
wherein t is a selected ratio of a maximum thickness of the airfoil between the first lateral face and the second lateral face to the length of the chord; and
wherein x is a position along the chord from a value of zero to a value equal to c.

5. The angle of attack sensor of claim 4 ,
wherein t is selected such that the maximum thickness of the airfoil between the first lateral face and the second lateral face is greater than a thickness of the heating element.

6. The angle of attack sensor of claim 1 ,
wherein the heating element comprises a first heating element; and
wherein the airfoil further comprises a second heating element disposed within the airfoil between the first and second lateral faces proximate the leading edge.

7. The angle of attack sensor of claim 1 ,
wherein the heating element comprises a self-regulated chip heater.

8. The angle of attack sensor of claim 1 , further comprising:
a communication device configured to output the rotational position sensed by the rotary position sensor.

9. The angle of attack sensor of claim 1 , further comprising:
an electronics interface connector exterior to the housing configured to output an electrical voltage from the rotary position sensor representative of the rotational position of the rotatable shaft.

10. The angle of attack sensor of claim 1 ,
wherein the airfoil is truncated at the trailing edge.

11. The angle of attack sensor of claim 10 ,
wherein the truncation is perpendicular to the chord of the airfoil.

12. An angle of attack sensor comprising:
a rotatable shaft;
a rotary position sensor configured to sense rotational position of the shaft; and
a vane, connected to the shaft,

Assignees

• Rosemount Aerospace Inc

Inventors

• Krueger William B
• Reid Alexander N
• Schwartz Richard Alan
• Freeman Kenneth

Classifications

• B64D45/00

  Aircraft indicators or protectors not otherwise provided for · CPC title

• B64D15/12

  by electric heating (heating arrangements specially adapted for transparent or reflecting areas H05B3/84) · CPC title

• B64D43/02

  for indicating aircraft speed or stalling conditions · CPC title

• G01P13/025 Primary

  indicating air data, i.e. flight variables of an aircraft, e.g. angle of attack, side slip, shear, yaw · CPC title