AERODYNAMIC MESS PROBE

Description

[0001] The invention relates to an aerodynamic measuring probe intended to measure a local incidence of airflow circulating along the fuselage of an aircraft, in particular an angle of attack (AOA) or sideslip (SSA) probe.

[0002] According to a known technique, aerodynamic measurement probes intended to measure an angle of attack (AOA) or a sideslip (SSA) include a rotating mobile assembly designed to orient itself in the axis of the airflow surrounding the aircraft on which the fixed support or support attached to the fuselage is installed.

[0003] Measuring the local incidence of airflow against an aircraft's fuselage is a crucial parameter for piloting. It allows us to define the direction of the aircraft's velocity vector relative to the surrounding ambient airflow.

[0004] The use of a mobile assembly located outside the aircraft therefore exposes it to severe environmental conditions, including the risk of icing.

[0005] It is known that probes have a protective plate with a flat geometry. This protective plate ensures geometric continuity with the fuselage of the carrier aircraft.

[0006] Known aerodynamic measurement probes do not allow for the maintenance of an aerodynamic measurement probe with an interface plate or hood having an optimized mass while guaranteeing mechanical strength, electrical continuity and thermal protection.

[0007] It is known, in document EP 3444618 B1, as illustrated on the figure 1 corresponding to figure 2B of document EP 3444618 B1, a probe with a flat protective plate. The rotating element 26 has a base 24 which is totally immersed under the flat plate 14.

[0008] Burying the base of the weather vane below the protective plate can impair measurement accuracy.

[0009] The absence of a flow stop point on the base of the weather vane produces a generation of return currents directed from downstream to upstream in the gap 50, considering the direction of the airflow.

[0010] Such a probe helps to limit convective exchanges with cold air (and the water droplets and crystals it carries) but impairs the accuracy of the measurement.

[0011] It is mentioned in document EP 3444618 B1, a flat plate made of aluminium or other metal, or of another suitable material in terms of thermal conduction, such as titanium, polymers or composite materials.

[0012] However, in one embodiment for example described in document EP 3444618 B1, if the interface plate or hood was implemented with a polymer, the mechanical strength of the hood under different loading conditions, resistance to degradation over time, as well as electrical continuity between the moving element and the fuselage are not ensured.

[0013] US2004188945A1 discloses a sealing device and NL2012457A discloses the molded manufacture of a structural connecting element

[0014] One aim of the invention is to overcome the problems mentioned above and in particular to ensure the retention of an aerodynamic measuring probe with an interface plate or hood having an optimized mass while guaranteeing mechanical strength, electrical continuity and thermal protection.

[0015] According to one aspect of the invention, an aerodynamic measuring probe is proposed for measuring the local incidence of airflow circulating along the fuselage of an aircraft, comprising a support, a heated body, and a shaft rotating about a longitudinal axis relative to the support and the body. The support, the body, and the shaft are configured to form a gap between them, allowing functional clearance to be maintained to permit one end of the shaft to rotate freely within the support and communicating with a circuit for the evacuation of impurities. The shaft comprises a portion internal to the support, a vane portion external to the support, and a base plate for the vane portion connecting the internal and external portions. The support comprises a circular hood or plate with a central opening through which the movable shaft passes. The external surface of the hood comprises a frustoconical face of revolution about the longitudinal axis.the hood comprising polyetheretherketone reinforced with glass or carbon fibers, with a thermal conductivity of less than 3 Wm-1.< K-1< , and being provided with metallic inserts at its fixings, at least one metallic insert being configured to make an electrical connection between the inner part of the probe and an interface of the metallic insert disposed under the lower periphery of the part of the metallic insert furthest from the shaft.

[0016] The use of a hood comprising polyetheretherketone reinforced with glass or carbon fibers, with a thermal conductivity of less than 3 Wm -1.< K -1< , equipped with metal inserts at its fixings, makes it possible to maintain an aerodynamic measurement probe with an interface plate or hood with an optimized mass while ensuring mechanical strength, and the presence of at least one metal insert for electrical continuity configured to make an electrical connection between the inner part of the probe and an interface of the metal insert located under the lower perimeter of the part of the metal insert furthest from the shaft.

[0017] Such materials make it possible to obtain a composite structural part by thermoplastic injection molding, with hollowing or stiffening zones to minimize its mass, an optimal contribution of glass fibers for mechanical reinforcement or the variation of certain material properties (coefficient of expansion) in certain preferred directions of the part (anisotropy) and the implantation of metallic inserts for the control of assembly, sealing and electrical continuity constraints inherent to the probe.

[0018] According to one embodiment, the hood comprises first stainless steel inserts arranged in a circular fashion towards the outside of the hood, and second brass inserts arranged in a circular fashion towards the inside of the hood.

[0019] Thus, thermal protection is enhanced by the presence of polyetheretherketone reinforced with glass or carbon fibers, with a thermal conductivity of less than 3 Wm⁻¹.K⁻¹, between the outer and inner rings of inserts. These inserts ensure mechanical strength under various load conditions by absorbing stresses and limiting the creep of the polyetheretherketone.

[0020] In one embodiment, a metallic electrical continuity insert comprises a first insert and a second insert, as well as a stainless steel portion connecting said first insert and said second insert.

[0021] Thus, electrical continuity is ensured between the internal part of the probe and the fuselage of the aircraft on which it is mounted.

[0022] According to one embodiment, the hood includes a clearance on its upper part, configured to access the upper part of the stainless steel portion of the electrical continuity metal insert, near its second insert.

[0023] The invention will be better understood upon examination of some embodiments described by way of non-limiting examples and illustrated by the attached drawing in which: [ Fig.1 ] schematically illustrates an aerodynamic measurement probe, according to the state of the art; ] Fig.2 ] schematically illustrates a cross-sectional view of an aerodynamic measuring probe, according to one aspect of the invention; [ Fig.3 ] schematically illustrates a top view of the probe cover, according to one aspect of the invention; [ Fig.4 ] schematically illustrates a view from below of the probe cover, according to one aspect of the invention; [ Fig.5 ] schematically illustrates a transparent bottom view of the probe cover, according to one aspect of the invention; [ Fig.6 ] schematically illustrates a cross-sectional view of the probe cover, passing through an external insert, according to one aspect of the invention; [ Fig.7 ] schematically illustrates a cross-sectional view of the probe cover, passing through an internal insert, according to one aspect of the invention; [ Fig.8 ] schematically illustrates a cross-sectional view of the probe cover, passing through an electrical continuity insert, according to one aspect of the invention; and [ Fig.9 ] schematically illustrates a clearance of the hood at the level of an electrical continuity insert, according to one aspect of the invention.

[0024] In this description, the embodiments described are not limiting, and features and functions well known to those skilled in the art are not described in detail.

[0025] On the figure 2 The upper part of an aerodynamic measuring probe intended to measure a local incidence of airflow circulating along the fuselage of an aircraft is schematically represented, comprising a support 1, in this case circular in shape, and a movable shaft 2 rotating about a longitudinal axis 3, relative to the support 1.

[0026] The support 1 and the movable shaft 2 are configured to form between them a gap 4 which allows to maintain a functional clearance to allow one end of the shaft 2 to rotate freely in the support 1, and which communicates with a circuit for evacuating impurities.

[0027] The tree 2 includes a part 2a internal to the support 1, a part 2b weather vane external to the support 1 and a plate 2c base or plinth of the weather vane part 2b connecting the internal part 2a and the external part 2b weather vane.

[0028] The body 5 contains a heating device as does the external wind vane part 2b of the shaft 2. The body 5 includes a central circular opening, through which the movable shaft 2 passes, and is sandwiched between the support 1 and a hood 6.

[0029] The support 1 includes the circular hood 6 with central opening, the circular opening of which is traversed by the movable shaft 2.

[0030] The hood 6 comprises polyetheretherketone reinforced with glass or carbon fibers, with a thermal conductivity of less than 3 Wm-1.< K-1< , and is provided with metal inserts 7, 8 at its fixings.

[0031] The cowling 6 includes an outer ring of first stainless steel inserts 7 arranged in a circular pattern outwards from the cowling 6 to secure the plate or cowling 6 to the aircraft fuselage. The cowling 6 also includes an inner ring of second brass inserts 8 arranged in a circular pattern inwards from the cowling 6 to secure the cowling 6 to the support 1.

[0032] A hood 6 comprising polyetheretherketone reinforced with glass or carbon fibers, with a thermal conductivity of less than 3 Wm -1.< K -1< , allows sufficient thermal insulation of the probe in severe flight conditions.

[0033] In addition, such materials have a density between 1200kg / m 3< and 1600kg / m 3< allowing for optimization of mass compared to an aluminium plate with a density of 2700kg / m 3<.

[0034] Furthermore, such materials are anisotropic (the property of being direction-dependent, and therefore exhibiting different characteristics depending on their orientation). The implementation of the cover 6 allows the glass or carbon fibers to be oriented in the horizontal plane, thus limiting the difference in coefficients of thermal expansion between the cover or interface plate 6 (18 ppm / °C in the direction of the plate's mean plane) and the aluminum counter plate at the aircraft fuselage (23 ppm / °C), and therefore the resulting thermomechanical stresses. Conversely, in the transverse plane, the thermal expansion of the polyetheretherketone reinforced with glass or carbon fibers is higher (greater than 40 ppm / °C).

[0035] The presence of metal inserts 7, 8 at its fixings ensures mechanical strength under various load cases such as screw tightening, differential expansion, pressure differential, vibration.

[0036] The hood 6 includes first overmolded stainless steel inserts 7 arranged in a circular fashion towards the outside of the hood 6, and second ultrasonically attached brass inserts 8 arranged in a circular fashion towards the inside of the hood 6.

[0037] The hood 6 includes at least one electrical continuity metal insert 9 configured to make an electrical connection between the inner part of the probe and an interface 13 of the metal insert 9 disposed under the lower periphery of the part of the metal insert furthest from the shaft 2.

[0038] THE figure 3 , figure 4 et figure 5 represent an embodiment of the hood 6 and the inserts 7, 8 and 9, respectively in top view, bottom view, and bottom view in transparency.

[0039] There figure 6 represents a cross-sectional view of a first stainless steel insert 7, and the figure 7 represents a cross-sectional view of a second brass insert 8.

[0040] For example, a metallic electrical continuity insert 9 comprises a first insert 7 and a second insert 8 and a stainless steel portion 10 connecting said first insert 7 and said second insert 8.

[0041] There figure 8 represents a cross-sectional view of such a metallic electrical continuity insert 9.

[0042] The presence of at least one such metallic electrical continuity insert 9 makes it possible to make the electrical link between the inside and outside of the probe, in order to be able to carry out a sufficiently reliable ground continuity verification measurement once the hood 6 has been installed on an aircraft and the fixing put in place.

[0043] There figure 9represents a clearance 11 of the hood 6 at the level of an electrical continuity insert 9, on the upper part of the hood 6. The clearance 11 is configured to access the upper part of the stainless steel portion 10 of the metal electrical continuity insert 9, near its second insert 8, so as to be able to perform a sufficiently reliable and easy ground continuity verification measurement once the hood 6 has been installed on an aircraft and the fastener put in place.

[0044] An aerodynamic measuring probe according to the present invention makes it possible to ensure the maintenance of an aerodynamic measuring probe with a hood having an optimized mass while guaranteeing mechanical strength, electrical continuity and thermal protection.

Claims

1. Aerodynamic measurement probe intended to measure a local angle of attack of an airflow circulating along the fuselage of an aircraft, comprising a support member (1), a heated body (5), and a shaft (2) able to rotate about a longitudinal axis (3) with respect to the support member (1) and the body (5), the support member (1), the body (5) and the shaft (2) being configured to form between them a gap (4) allowing functional play to be maintained so as to allow one end of the shaft (2) to pivot freely in the support member (1), and communicating with a circuit for discharging impurities, the shaft (2) comprising a part (2a) internal to the support member (1), a vane part (2b) external to the support member (1) and a base plate (2c) of the vane part (2b) connecting the internal part (2a) and the external part (2b), the support member (1) comprising a circular lid (6) with a central opening through which passes the movable shaft (2), the outer surface of the lid (6) comprising a frustoconical face (6a) exhibiting symmetry of revolution about the longitudinal axis (3), characterised in that the lid (6) comprises polyether ether ketone reinforced with glass or carbon fibres, with a thermal conductivity of less than 3 W.m-1 K-1, and is provided with metallic inserts (7, 8) at its fastenings, at least one metallic electrical continuity insert (9) being configured to establish an electrical connection between the inner part of the probe and an interface (13) of the metallic insert (9) arranged under the lower periphery of that part of the metallic insert which is furthest away from the shaft (2).

2. Probe according to claim 1, wherein the lid (6) comprises first inserts (7) made of stainless steel and arranged in a circular manner toward the outside of the lid (6), and second inserts (8) made of brass and arranged in a circular manner toward the inside of the lid (6).

3. Probe according to claim 2, wherein a metallic electrical continuity insert (9) comprises a first insert (7) and a second insert (8), and a stainless steel portion (10) connecting said first insert (7) and said second insert (8).

4. Probe according to any one of the preceding claims, wherein the lid (6) comprises a clearance (11) on its upper part, which clearance is configured for access to the upper part of the stainless steel portion (10) of the metallic electrical continuity insert (9), in the vicinity of its second insert (8).