US-12618864-B2 - Aerodynamic measurement probe

US12618864B2US 12618864 B2US12618864 B2US 12618864B2US-12618864-B2

Abstract

An aerodynamic measurement probe intended to measure a local angle of attack of an air stream flowing along the fuselage of an aircraft, includes a support and a shaft that is able to rotate about a longitudinal axis with respect to the support, the support and the shaft being configured to form between them a gap, passing around an annular tab at the end of the shaft in the support, making it possible to maintain a functional clearance to allow one end of the shaft to pivot freely in the support, and communicating with an impurity discharge circuit, the gap comprising an inner annular groove about the axis of rotation, made in the support, and opening out away from the axis directly onto the end part of the annular tab, the profile of the inner groove being rounded.

Inventors

Natacha SZULGA
François Perez
Eric Loil
Frédéric SADRIN
Jocelyn BE
Jean-Luc VALLEE
Tristan GUILLABEAU

Assignees

THALES

Dates

Publication Date: 20260505
Application Date: 20220520
Priority Date: 20210527

Claims (16)

1 . An aerodynamic measurement probe to measure a local angle of attack of an air stream flowing along an aircraft fuselage, said probe comprising: a support and a shaft, said shaft being able to rotate about a longitudinal axis with respect to the support, the support and the shaft being configured to form between them a gap, said gap passing around an annular tab of an end of the shaft in the support, maintaining a functional clearance allowing said end of the shaft to pivot freely in the support, and said gap communicating, through an annular groove with drain holes of an impurity discharge circuit, the gap comprising an inner annular groove about the longitudinal axis, the inner groove being made in the support, and the inner groove opening out away from the axis directly onto an end part of the annular tab, wherein the gap further comprises said outer annular groove, about the longitudinal axis, made in the support, and opening out toward the axis, so that the annular tab is positioned directly between the inner and outer grooves; the outer groove, the tab, the inner groove and a chicane downstream the inner groove protecting mechanical rotation elements of the probe from impurities, impurities being drained through the drain holes away from said mechanical rotation elements to be discharged by gravity.
2 . The probe as claimed in claim 1 , wherein the profile of the outer groove is rectangular.
3 . The probe as claimed in claim 2 , wherein the rectangular profile of the outer groove has a height (a) of between 1.5 mm and 4 mm.
4 . The probe as claimed in claim 3 , wherein the rectangular profile of the outer groove has a height (a) of 3 mm.
5 . The probe as claimed in claim 2 , wherein the rectangular profile of the outer groove has a depth (b) of between 3 mm and 7 mm.
6 . The probe as claimed in claim 5 , wherein the rectangular profile of the outer groove has a depth (b) of 4.5 mm.
7 . The probe as claimed in claim 6 , wherein a rounded profile of the inner groove has a diameter (d) of between 2 and 5 mm.
8 . The probe as claimed in claim 7 , wherein a rounded profile of the inner groove has a diameter (d) of 3.2 mm.
9 . The probe as claimed in claim 1 , wherein the profile of the inner groove is rectangular.
10 . The probe as claimed in claim 9 , wherein the profile of the rectangular inner groove has a height of between 2 mm and 5 mm.
11 . The probe as claimed in claim 1 , wherein the gap comprises a substantially straight first part, having a width (f) of between 1 mm and 5 mm, between a part of the gap emerging into open air and the outer groove.
12 . The probe as claimed in claim 11 , wherein the first part of the gap has a width (f) of 1.2 mm.
13 . The probe as claimed in claim 1 , wherein the gap comprises a substantially straight second part, between the outer groove and the inner groove, having a width (c) of between 0.5 mm and 1 mm.
14 . The probe as claimed in claim 13 , wherein the second part of the gap has a width (c) of 0.65 mm.
15 . The probe as claimed in claim 1 , wherein the gap comprises a substantially straight third part, forming the chicane, positioned between the inner groove and a fourth part of the gap in contact with mechanical elements of a movable shaft allowing the rotation thereof, said third part having a width (e) of between 0.5 mm and 1 mm.
16 . The probe as claimed in claim 15 , wherein the third part of the gap has a width (e) of 0.65 mm.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a National Stage of International patent application PCT/EP2022/063759, filed on May 20, 2022, which claims priority to foreign French patent application No. FR 2105489, filed on May 27, 2021, the disclosures of which are incorporated by reference in their entireties. FIELD OF THE INVENTION The invention relates to an aerodynamic measurement probe intended to measure a local angle of attack of an air stream flowing along the fuselage of an aircraft, in particular an angle-of-attack (AOA) probe or a side-slip angle (SSA) probe. BACKGROUND According to one known technique, aerodynamic measurement probes intended to measure an angle of attack (AOA) or a side-slip angle (SSA) comprise a rotatable assembly intended to be oriented in line with the air stream surrounding the aircraft on which the support, fixed or rigidly connected to the fuselage, is installed. The measurement of the local angle of attack of an air stream on the fuselage of an aircraft is an essential parameter for piloting the latter. It makes it possible to define the direction of the velocity vector of the aircraft with respect to the ambient air flow surrounding it. The use of a movable assembly poses the problem of sealing the movable assembly with respect to its support, embedded in the fuselage of the aircraft. Means must be provided for preventing or limiting the penetration of liquid or other foreign bodies into the mechanism of the probe. Various solutions comprising sealed bearings, involving dry friction or viscous friction, have been envisaged to overcome this difficulty. These solutions offer variable sealing performance and can be dimensioned in accordance with the requirements of the aircraft. Impurities can reach these bearings and seize or jam them. To prevent this, it is possible to seal the gap with a deformable protector, to the detriment of the measurement accuracy/sensitivity, or to allow foreign bodies to enter, and manage the discharge thereof. However, dry or viscous friction between the pin and the support generates torque that resists the rotation of the movable assembly. To meet the most stringent requirements in terms of the accuracy and response time of aerodynamic probes, the use of pins that rotate in a frictionless manner with respect to the support has been envisaged. To allow the pin to rotate freely, the rotating pin is connected to the support by a set of bearings for guiding in rotation, without seals or other sealing means in contact with the pin. It is therefore accepted that impurities, such as water droplets, ice particles, grains of sand, dust, soot particles, etc., can penetrate at the interface between the pin and the support. For these devices having a pin that rotates in a frictionless manner, there is nevertheless a desire to limit the quantity of penetrating impurities. Aircraft are subject to extreme environments in which soot, dust and ice particles and/or water droplets are borne by the fluid flow. Probes must be robust to withstand these environments. The DO-160 approval tests set out for example extreme test conditions (sand and dust, water ingestion, icing) that the probes must withstand in order to demonstrate their robustness in operational conditions. Known AOA probe C16291AB, developed by Thales, has a very large functional clearance between the mounting plate and the rotating part. This functional clearance communicates with a void situated under the mounting plate. The drain hole is systematically pointing downward. The large size of the functional clearance prevents the rotating part from being jammed by a build-up of small particles (or by the larger particles of the DO-160 sand tests). The large void volume under the mounting plate “stores” the particles without the risk of jamming the rotating part if the discharge speeds of the drain hole are insufficient. The management of the particles ingested by this probe is based on the functional clearance between the movable part and the fixed part. This clearance, which is large compared to the dimensions of the particles usually encountered, prevents the vane from being jammed by solid particles. However, this large clearance promotes intense heat exchanges with the air at the base of the vane. This makes this first solution vulnerable to icing. U.S. Ser. No. 10/393,766 B2 is also known, which discloses a system for managing water entering an angle-of-attack probe. A solution with four drain holes is disclosed, two of which are always pointing downward. The functional clearance of the probe is connected to all of the drain holes by a significant volume under the fixed part of the probe. In the same way, this large volume stores water if the exit speeds of the drain holes are insufficient. It must be noted that this system for managing the water ingested by the probe allows water to access the electronic unit of the probe in certain situations. Such a probe addresses the problem