Aerodynamic measurement probe
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.
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.