GB2148749A

GB2148749A - Air intake for aircraft engines

Info

Publication number: GB2148749A
Application number: GB08425504A
Authority: GB
Inventors: Santino Pancotti; Luigi Tortorella
Original assignee: Costruzioni Aeronautiche Giovanni Augusta SpA
Current assignee: Agusta SpA
Priority date: 1983-10-26
Filing date: 1984-10-09
Publication date: 1985-06-05
Also published as: JPS60209637A; IT8368106A0; DE3439160A1; FR2554172A1; GB8425504D0; IT1161528B

Abstract

An air intake filter (4) for aircraft, particularly helicopter, engines, comprises a box (5) having an inner compartment (14, 15) specially shaped so as to define, upstream of a respective engine air intake (3), when the filter is mounted on the aircraft fuselage 1, a chamber (36) which communicates with the atmosphere through separating passages (37, 38) extending through and communicating with the said compartment (14, 15). The latter communicates with the atmosphere through a pipe (22) supporting a ducted power fan (31). <IMAGE>

Description

SPECIFICATION Air intake filter for aircraft, particularly helicopter, engines The present invention relates to an air intake filter for aircraft, particularly helicopter, engines.

On aircraft, as on any motor vehicle, steps must be taken to ensure air intake on the engines is free from impurities which might damage the engine or impair its performance and efficiency.

Engine air intake filtration is especially important on helicopters, on account of their ability to operate close to the ground and on account of the dust raised by the rotors, especially when operating over dry or sandy terrain. On known types of helicopters, engine air intakes are usually protected by means of filters, usually comprising a dust separating box through which intake air is blown. As the air blows through the box, suspended dust is removed from it and trapped inside the box itself. The latter is provided with a dumping port through which the trapped dust is dumped out under pressure, usually generated inside the said box by connecting it, by means of external piping, either to the engine exhaust pipes or to fans on the helicopter.

The aforementioned known types of filter involve a number of drawbacks, on account of both size and weight and the fact that, being provided with the said external piping, they form an integral part of the helicopter, and not a separate unit enabling troublefree assembly and maintenance, or an accessory to be used only when needed. The aim of the present invention is to provide a filter involving none of the aforementioned drawbacks.

With this aim in view, the present invention relates to an air intake filter for aircraft, particularly helicopter, engines, characterised by the fact that it comprises, in due combination, a box, having an inner compartment designed to define a chamber before a respective air intake on a respective said engine, dust separating passages formed through the said box for enabling external communication of the said chamber, each said passage communicating with the said inner compartment, and a dust exhaust pipe extending outwards of the said box and communicating with the said compartment; a fan being housed in rotary manner inside the said exhaust pipe and actuating means being supported by the said box for driving the said fan.

A non-limiting arrangement of the present invention will now be described with reference to the attached drawings in which: Fig. 1 shows a cross section, with parts removed for clarity, of a helicopter portion comprising a filter according to the present invention; Fig. 2 shows a side view of a detail in Fig. 1; Fig. 3 shows an end view of the Fig. 2 detail.

Number 1 in Fig. 1 indicates a helicopter fuselage, which usually presents, at the top, a compartment 2 housing the inlet of an air intake 3 for the engine (not shown) powering the rotor (not shown) on the helicopter.

Compartment 2 is fully shielded outwardly by a filter, indicated as a whole by 4, comprising a box 5 having an essentially L-shaped section and, in turn, comprising a top arm 6, extending outwards from a first point on fuselage 1 in an essentially horizontal direction, and a side arm 7 communicating with the outer side end of arm 6 and extending from it downwards to a second point on fuselage 1.

In shape, arm 6 is essentially a rectangular parallelepipedon limited by a top wall 8, a bottom wall 9 facing compartment 2 and essentially parallel with wall 8, and an inner side wall 10 along the top side edge of which is provided a bracket 11 designed to hinge, in easily removable manner, filter 4 to fuselage 1.

Arm 6 is limited front- and rearwards by two walls, 12 and 13, essentially L-shaped when viewed from the top and extending as far as arm 7. Together with walls 8,9 and 10, walls 12 and 13 define an essentially rectangular parallelepiped compartment 14 an outer side end of which, opposite wall 10, communicates with the top end of an inner compartment 15 on arm 7 limited at the front and rear ends by walls 12 and 13.

Compartment 15 is limited by an inner side wall 16 and an outer side wall 17 blended respectively to the outer ends of walls 9 and 8 and connected together by a bottom wall 18 provided externally with an angle section 19 designed to connect, in removable manner, to fuselage 1.

At the bottom end, compartment 15 presents a flared portion 20 communicating externally through a round hole 21 through wall 17 and engaged by the inner end of pipe 22. The latter presents a flange 23 for connection to wall 17 from which it extends outwards for supporting a downturned pipe 24 on its free end.

Pipe 22 supports internally, by means of supports 25, a tubular body 26 defining, inside pipe 22, an annular-section passage 27 communicating externally, on one side, through pipe 24 and, on the other, with compartment 15. Tubular body 26 houses an electric motor 28 supplied over cable 29 and having an output shaft 30 facing compartment 15 and fitted with an extraction fan 31 housed inside portion 32 of pipe 22 extending inside the flared portion 20 of compartment 15.

In an alternative arrangement not shown, output shaft 30 faces outwards and supports fan 31 inside the part of pipe 22 extending outside compartment 15, whereas electric motor 28 is at least partially housed inside compartment 15.

As shown in Fig. 3, walls 12 and 13 are connected integral with two plates, 33 and 34, the outer edge 35 of which is appropriately shaped to mate with the outer surface of fuselage 1 and define, together with the latter and walls 9 and 16, a chamber 36 communicating with the air intake 3 on the helicopter engine (not shown).

Chamber 36 communicates with a number of truncated-cone pipes 37 fitted through walls 9 and 16 with their smaller ends inside respective compartments 14 and 15. Each pipe 37 engages, with radial slack, a respective cylindrical pipe 38 fitted through the relative wall 8, 17 and defining, with the relative pipe 37, an annular opening 39 communicating with the relative compartment 14, 15.

A centrifugal element 40 is fitted, in fixed manner, inside an inlet portion of each pipe 38.

During operation, air, and any dust suspended in it is forced at relatively high speed into pipes 38 both by the movement imparted by the blades (not shown) on the rotor (not shown) of helicopter land by the vacuum created by the motors inside chamber 36. The in-coming air is then swirled by elements 40 so as to cause any suspended dust to be hurled inside compartments 14 and 15 of box 5 through openings 39, while part of the in-coming air proceeds, after filtering, into chamber 36 through pipes 37.

The combined action of air pressure, gravity and the vacuum formed by fan 31 causes the separated dust to drop down into the flared portion 20 of compartment 15 from where it is dumped out through annular passage 27 and pipe 22, the latter of which may, in certain applications, be dispensed with.

When not required,filter4 may be removed in a few minutes, and replaced with a mesh, by simply removing section 19 and releasing bracket 11.

Claims

1. Air intake filter for aircraft, particularly helicopter, engines, characterised by the fact that it comprises, in due combination, a box, having an inner compartment designed to define a chamber before a respective air intake on a respective said engine, dust separating passages formed through the said box for enabling external communication of the said chamber, each said passage communicating with the said inner compartment, and a dust exhaust pipe extending outwards of the said box and communicating with the said compartment; a fan being housed in rotary manner inside the said exhaust pipe and actuating means being supported by the said box for driving the said fan.

2. Filter according to Claim 1, characterised by the fact that the said actuating means are housed inside the said exhaust pipe.

3. Filter according to Claim 1 or 2, characterised by the fact that the said exhaust pipe extends from a flared bottom portion of the said compartment.

4. Air intake filter for aircraft engines, essentially as described and illustrated with reference to the attached drawings.