ITUB20154090A1 - AIR INTAKE UNIT FOR THE PROPELLER OF AN AIRCRAFT - Google Patents

Description

DESCRIPTION

"AIR INTAKE UNIT FOR AIRCRAFT THRUSTER"

TECHNIQUE SECTOR

The present invention relates to an air suction unit for the propeller of an aircraft, that is a machine built by man that supports itself and can be moved in the air allowing the transport of people or things inside the earth's atmosphere. .

The present invention finds advantageous application to a helicopter, to which the following discussion will make explicit reference without thereby losing generality.

ANTERIOR ART

A modern helicopter is generally equipped with at least one turbine propeller that drives a complex of blades that allow the helicopter itself to rise and fall vertically, remain stationary in flight, move sideways, backwards or forwards. The turbine engine has an air intake at the front, through which the turbine engine sucks in the external air necessary for its operation (i.e. the external air containing the oxygen necessary for combustion).

Generally, the air intake may comprise a metal grid with relatively large meshes (of the order of magnitude of one or two centimeters) which has the function of preventing the entry of birds. More rarely, between the air intake and the turbine engine there is an air filter with the function of filtering the intake air to retain small impurities (dust or similar) which in the long run can cause premature wear of the engine. turbine. The use of the air filter is generally avoided, as the air filter causes pressure drops that have a significant negative impact on the performance of the turbine engine and is only useful near the ground; in fact, impurities tend to descend downwards by gravity and therefore can be present in the air only close to the ground, while at high altitudes (for example over 50-70 meters above the ground) the air is completely free of impurities. Consequently, the air filter is only fitted when the helicopter has to operate (particularly take off or land) in very dusty areas such as desert areas.

However, it has been observed that the absence of the air filter generally leads to an increase in the maintenance costs of the engine due to the increased wear caused by the entry of foreign bodies into the combustion chamber during take-off and landing (i.e. when the helicopter stands close to the ground). In fact, even taking off and landing only in heliports (therefore on asphalted surfaces or similar) it is inevitable that the strong air currents generated by the rotation of the blades lift and circulate impurities (essentially dust and small debris) which are always present in the external environment.

DESCRIPTION OF THE INVENTION

The object of the present invention is to provide an air suction unit for the propeller of an aircraft which allows the aircraft to operate safely even in very dusty areas without presenting, at the same time, any performance penalty.

According to the present invention, an air suction unit is provided for the propeller of an aircraft, according to what is claimed by the attached claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described with reference to the attached drawings, which illustrate some non-limiting examples of implementation, in which:

Figures 1, 2 and 3 are schematic and side, front and top views respectively of a helicopter provided with a pair of twin turbine thrusters provided with corresponding air intake units made in accordance with the present invention;

Figure 4 is a schematic and longitudinal section view of an air suction unit of figure 1 with a shutter device in a closed position;

Figure 5 is a schematic and longitudinal section view of the air suction unit of figure 4 with the shutter device in an open position;

Figure 6 is a schematic and longitudinal section view of an alternative embodiment of the air suction unit of figure 4 with the shutter device in a closed position; Figure 7 is a schematic and longitudinal section view of the air suction unit of figure 6 with the shutter device in an open position;

Figures 8 and 9 are two schematic and front views of the air suction unit of Figure 6 with the shutter device respectively in a closed position and in an open position; And

Figure 10 is a schematic and perspective view of an element of the shutter device of the air suction unit of figure 6.

PREFERRED FORMS OF IMPLEMENTATION OF THE INVENTION

In figures 1, 2 and 3, the number 1 indicates as a whole a helicopter comprising two twin turbine propellers 2 which operate a set of blades which allow the helicopter itself to rise and lower vertically, remain stationary in flight, move sideways , backwards or forwards.

Each turbine propeller 2 comprises a tubular housing having an air inlet opening at the front (through which the turbine propeller 2 sucks in the external air necessary for its operation, i.e. the external air containing the oxygen necessary for combustion) and at the rear an air outlet opening (through which the turbine propeller 2 expels the exhaust gases produced by combustion). At the air inlet opening of each turbine propeller 2 there is an air intake unit 3 through which the air sucked by the turbine propeller 2 flows.

According to what is illustrated in Figures 4 and 5, the suction unit 3 comprises a tubular housing 4 which has a longitudinal axis 5 of symmetry and is provided with an external wall 6 which delimits the space enclosed by the tubular housing 4 itself.

The suction unit 3 comprises an inlet opening 7 which is formed through the outer wall 6 of the tubular housing 4 and through which the external air necessary for the operation of the turbine propeller 2 can be sucked; in other words, the external air necessary for the operation of the turbine propeller 2 can enter the tubular housing 4 passing through the inlet opening 7 and therefore from the interior of the tubular housing 4 can reach the propeller 2 a turbine. In the embodiment illustrated in Figure 4, the suction unit 3 comprises a single inlet opening 7, but according to other embodiments not illustrated and perfectly equivalent, the suction unit 3 comprises several inlet openings 7 side by side.

The suction unit 3 comprises an air filter 8 which is supported by the tubular housing 4 and fully engages the inlet opening 7 to filter the external air flowing through the inlet opening 7 and entering the tubular housing 4. ; in other words, the air filter 8 reproduces the shape of the inlet opening 7 so as to engage the inlet opening 7 without play and thus filter all the air that passes through the inlet opening 7 to enter the 4 tubular housing. In the embodiment illustrated in the attached figures, the air filter 8 has a tubular shape (in which the filtering material is arranged in correspondence with the side wall). Preferably, the air filter 8 comprises a cylindrical or truncated cone-shaped support frame (made of aluminum, plastic or composite material) which is fixed to the outer wall 6 of the tubular housing 4 and supports several curved panels of material filtering material (for example made of fabric or non-woven fabric of cotton or other fibers enclosed between two layers of thin metal mesh that give shape and resistance to the filtering material itself).

The suction unit 3 comprises a pair of inlet openings 9, each of which is formed through the outer wall 6 of the tubular housing 4 and is completely separate and independent from the inlet opening 7 and the air filter 8. Through the inlet openings 9, the external air necessary for the operation of the turbine propeller 2 can be sucked in; in other words, the external air necessary for the operation of the turbine propeller 2 can enter the tubular housing 4 passing through the inlet openings 9 and therefore from the interior of the tubular housing 4 can reach the turbine propeller 2 . In the embodiment illustrated in Figure 4, the suction unit 3 comprises two inlet openings 9, but according to other embodiments not illustrated and perfectly equivalent, the suction unit 3 comprises a single inlet opening 9 or more than two entrance openings 9 side by side.

As previously mentioned, the air filter 8 has a tubular shape in which the filter material is arranged in correspondence with the side wall and has respective free openings at the front and rear: the front opening allows the passage of air coming from the two openings 9 of inlet while the rear opening allows the sucked air to flow towards the turbine propeller 2.

The suction unit 3 comprises a shutter device 10 which is arranged inside the tubular housing 4, is coupled to each inlet opening 9 and is movably mounted to move between a closed position (illustrated in Figure 4) in which it closes the inlet opening 9 (to prevent the entry of air through the inlet opening 9) and an open position (illustrated in Figure 5) in which it allows free passage through the inlet opening 9 (to allow air inlet through the inlet opening 9).

Finally, the suction unit 3 comprises an actuator 11 (for example an electric motor or a pneumatic or hydraulic cylinder) which moves the shutter device 10 between the closed position and the open position.

When the shutter device 10 is in the closed position (illustrated in Figure 4), the external air can enter the tubular housing 4 (and therefore reach the turbine propeller 2) only by passing through the inlet opening 7 and then passing through the 8 air filter. On the other hand, when the shutter device 10 is in the open position (illustrated in Figure 5), the external air can enter the tubular housing 4 (and therefore reach the turbine propeller 2) either by passing through the inlet opening 7 and therefore passing through the air filter 8, or passing through the inlet openings 9 and therefore without passing through the air filter 8 (the inlet openings 9 being devoid of filtering material do not present any obstacle to the passage of air). Obviously, when the shutter device 10 is in the open position (illustrated in Figure 5), almost all of the air that enters the tubular housing 4 to reach the turbine drive 2 passes through the inlet openings 9 rather than through the the inlet opening 7 engaged by the air filter 8, since the crossing of the inlet openings 9 has less pressure drops.

When the shutter device 10 is in the closed position (illustrated in Figure 4), the sucked air necessarily passes through the inlet opening 7 and through the air filter 8; therefore any impurities present in the air are blocked by the air filter 8 but on the other hand the passage through the air filter 8 causes a pressure drop in the intake air which penalizes the performance of the turbine propeller 2. On the other hand, when the shutter device 10 is in the open position (illustrated in Figure 5) the sucked air passes mainly through the inlet openings 9 and any impurities present in the air are not blocked by the air filter 8; therefore there is no pressure drop in the intake air but on the other hand any impurities present in the air are not blocked by the air filter 8.

According to what is illustrated in Figures 4 and 5, an electronic control unit 12 is provided, which supervises the operation of the air suction unit 3 and, among other things, drives the actuator 11 to move the shutter device 10 between the closed position (illustrated in Figure 4) and the open position (illustrated in Figure 5). In particular, when the helicopter 1 is close to the ground (during take-off or landing or when stationed at low altitude), it is possible (probable) that the sucked air contains impurities and therefore the shutter device 10 is arranged and maintained by the electronic control unit 12 in the closed position to filter the intake air; on the other hand, when the helicopter 1 is at a height (i.e. far from the ground, for example at a height of a few tens of meters), it is very unlikely that the sucked air contains impurities and therefore the shutter device 10 is arranged and maintained by the unit 12 for electronic control in the open position to avoid penalizing (unnecessarily) the performance of the turbine engine 2.

Furthermore, the electronic control unit 12 is connected to a pressure sensor 13, which is arranged in the tubular housing 4 downstream of the filter material of the air filter 8 and measures the pressure of the intake air after passing through the 8 air filter; when the inlet air pressure measured by the pressure sensor 13 is lower than a threshold value, the shutter device 10 is arranged and maintained by the electronic control unit 12 in the open position (illustrated in Figure 5) regardless of the proximity of the 1 helicopter on the ground. In other words, the intake air pressure measured by the pressure sensor 13 indicates the clogging of the air filter 8, since the more the air filter 8 is clogged, the lower the intake air pressure measured by the sensor. 13 of pressure; therefore, when the air filter 8 is too clogged, or when the inlet air pressure measured by the pressure sensor 13 is lower than a threshold value, the shutter device 10 is arranged and maintained by the electronic control unit 12 in the position open (illustrated in Figure 5) to avoid excessively penalizing the performance of the turbine propeller 2.

In the embodiment illustrated in the attached figures, the tubular housing 4 has a front portion 14 which is shaped like an ogive and through which the inlet openings 9 are made and a rear portion 15 of a truncated cone shape through which it is made the entrance opening 7; therefore, in the embodiment illustrated in the attached figures, the inlet openings 9 are arranged in the front position and therefore in front of the inlet opening 7 which is arranged in the rear position. According to other embodiments not shown, the inlet opening 7 is arranged in the front position and therefore in front of the inlet openings 9 which are arranged in the rear position. It is important to note that during the advancement of the helicopter 1 the front position allows to intercept, with the same surface, a greater quantity of air and therefore the inlet openings 9 arranged in the forward position have an advantage with respect to the inlet opening 7 arranged in the rear position.

In the embodiment illustrated in the attached figures, the rear portion 15 of the tubular housing 4 has a frusto-conical shape; consequently, also the inlet opening 7 and the air filter 8 which engages the inlet opening 7 have a truncated cone shape (having the smaller base at the front and the larger base at the rear). According to a different embodiment not shown, the rear portion 15 of the tubular housing 4 has a cylindrical shape; consequently, the inlet opening 7 and the air filter 8 which engages the inlet opening 7 also have a cylindrical shape.

The shutter device 10 comprises for each inlet opening 9 a corresponding bulkhead 16 which is mounted movably between the open position (illustrated in Figure 4) and the closed position (illustrated in Figure 5). In particular, each bulkhead 16 is hinged to rotate between the open position and the closed position about an axis 17 of rotation.

In the embodiment illustrated in Figures 4 and 5, the two bulkheads 16 are separate from each other (i.e. they are constituted by respective elements having their own movement) which rotate around respective rotation axes 17 which are parallel to each other and are transverse to the longitudinal axis 5 of symmetry of the tubular housing 4. Basically, in the embodiment illustrated in Figures 4 and 5, each bulkhead 16 is a panel which reproduces the shape of the corresponding inlet opening 9 and is slightly larger than the inlet opening 9 itself.

In the embodiment illustrated in Figures 6-10, the two bulkheads 16 form a single tubular body (illustrated separately in Figure 10) shaped like an ogive (i.e. shaped like the front portion 14 of the tubular housing 4) which is arranged inside of the front portion 14 of the tubular housing 4 in contact with the outer wall 6 of the tubular housing 4 itself. In this embodiment, the axis 17 of rotation of the bulkheads 16 is coaxial with the longitudinal axis 5 of the tubular housing 4. Furthermore, in this embodiment, each bulkhead 16 comprises a through hole 18 which in the closed position (illustrated in Figures 6 and 8) is far from the corresponding inlet opening 9 and in the open position (illustrated in Figures 7 and 9) is superimposed. at the corresponding entrance opening 9,

According to a possible (but not binding) embodiment, in correspondence with each inlet opening 9 a metal grid with relatively large meshes (of the order of magnitude of one or two centimeters) can be arranged which has the function of avoiding the entry of birds.

The embodiment illustrated by way of example in the illustrated figures refers to a turbine propeller 2, but the present invention can find advantageous application in any type of propeller for an aircraft.

The embodiment illustrated by way of example in the illustrated figures relates to a helicopter 1, but the present invention can find advantageous application in any type of aircraft, therefore also to an airplane.

The air suction unit 3 described above has numerous advantages.

Firstly, the air intake unit 3 described above allows the aircraft 1 to operate safely in very dusty areas (therefore in areas where the air near the ground is rich in impurities raised both by natural wind, both by the air currents generated by the propulsion of the aircraft 1) thanks to the presence of the air filter 8 which, if necessary, is made operational (by placing the shutter device 10 in the closed position) to preventively filter the air sucked in by the turbine propeller 2 .

Furthermore, the air intake unit 3 described above can operate for the great majority of the flight without any performance penalty, since when the aircraft 1 is at altitude (i.e. relatively far from the ground) the air filter 8 is bypassed ( placing the shutter device 10 in the open position).

Finally, the air suction unit 3 described above is easy and inexpensive to manufacture since the movement of the shutter device 10 can be carried out in a simple way and with components available on the market.

Claims (11)

R IV E N D IC A T IO N I 1) Air intake unit (3) for the propeller of an aircraft (1); the suction unit (3) includes: a tubular housing (4) provided with an outer wall (6); at least a first inlet opening (7) which is formed through the outer wall (6) of the tubular housing (4) and through which the external air necessary for the operation of the propeller (2) can be sucked; and at least one air filter which is supported by the tubular housing (4) and engages the first inlet opening (7) for filtering the external air flowing through the first inlet opening (7) itself; the suction unit (3) is characterized by the fact that it comprises: at least a second inlet opening (9) which is obtained through the outer wall (6) of the tubular housing (4), is separate and independent from the first inlet opening (7) and the air filter and through which it can be sucked in the external air necessary for the operation of the engine (2); a shutter device (10) which is coupled to the second inlet opening (9) and is movably mounted to move between a closed position in which the second inlet opening (9) closes and an open position in which it allows free passage through the second entrance opening (9); and an actuator (11) which moves the shutter device (10) between the closed position and the open position. 2) Air suction unit (3) according to claim 1, wherein the tubular housing (4) has a front portion (14) which is shaped like an ogive and through which the second inlet opening (9) is obtained and a rear portion (15) through which the first inlet opening (7) is formed. 3) Air suction unit (3) according to claim 2, wherein the rear portion (15) has a frusto-conical shape. 4) Air suction unit (3) according to claim 2 or 3, in which the air filter has a tubular shape in which the filter material is arranged in correspondence with the side wall and has respective free openings at the front and rear. 5) Air suction unit (3) according to one of claims 1 to 4, wherein the shutter device (10) is arranged inside the tubular housing (4). 6) Air suction unit (3) according to one of claims 1 to 5, wherein the shutter device (10) comprises a bulkhead (16) which is movably mounted between the open position and the closed position. 7) Air suction unit (3) according to claim 6, wherein the bulkhead (16) is hinged to rotate between the open position and the closed position about a rotation axis (17). 8) Air suction unit (3) according to claim 7, wherein the axis (17) of rotation is transverse to a longitudinal axis (5) of symmetry of the tubular housing (4). 9) Air suction unit (3) according to claim 7, wherein the axis (17) of rotation is coaxial to a longitudinal axis (5) of symmetry of the tubular housing (4). 10) Air suction unit (3) according to claim 9, wherein the bulkhead (16) comprises a through hole (18) which in the closed position is away from the second inlet opening (9) and in the open position is superimposed on the second entrance opening (9). 11) Air suction unit (3) according to claim 10, wherein: the tubular housing (4) has a front portion (14) which is shaped like an ogive and through which the second inlet opening (9) is made and a rear portion (15) through which the first opening (7) is made ) input; And the bulkhead (16) is shaped like an ogive taking up the shape of the front portion (14) of the tubular housing (4) and is arranged inside the front portion (14) of the tubular housing (4) in contact with the wall ( 6) outside the tubular housing (4) itself.