GB2133365A

GB2133365A - Improvements in or relating to helicopters

Info

Publication number: GB2133365A
Application number: GB08332083A
Authority: GB
Inventors: Egon Spitzer
Original assignee: Individual
Current assignee: Individual
Priority date: 1982-12-01
Filing date: 1983-12-01
Publication date: 1984-07-25
Also published as: GB8332083D0

Abstract

A safety device for deploying a parachute from a helicopter in the event of engine or rotor failure, comprises a tubular housing member 10 telescopically mounted within the hollow upper end of the helicopter rotor shaft 4 and slidable from a retracted position to an extended position in which the housing projects substantially above the plane of rotation of the helicopter's rotor blades, a cannister 14 rotatably mounted in the housing 10 and containing a folded parachute having lines fastened to the cannister, and ejector means which is operable in an emergency, instantaneously to extend the housing and eject the parachute from the upper end of the cannister. In its extended position the housing 10 ensures that the parachute and lines are spaced well away from the rotor and will not snag the rotor as and when the parachute is deployed. The ejector means may be a spring, compressed gas, or a pyrotechnic cartridge. <IMAGE>

Description

SPECIFICATION Improvements in or relating to helicopters The present invention relates to helicopters and, particularly, to a safety device for use with helicopters and for deploying a parachute to reduce the rate of descent of a helicopter in the event of an emergency.

A fundamental danger with helicopters is that a loss of power causes an immediate loss of lift.

Thus, an aeroplane which loses its motive power retains the possibility of a form of controlled flight by gliding, but this is not so with a helicopter.

Furthermore, the rotors of helicopters are more fragile than the wings of an aeroplane, particularly, in respect of their connections to their drive means and to the linkages which control the angles of attack of individual rotor blades. Rotor failure of a helicopter in flight is almost always catastrophic.

The present invention has for an object to reduce the danger to helicopter users caused by engine or rotor failure.

To this end, the invention consists in a helicopter comprising a rotor shaft, a housing member telescopically mounted within a hollow upper end of the rotor shaft and slidable through the top of the rotor shaft from a retracted position to an extended position in which the housing member projects above the plane of rotation of the rotor blades, a folded parachute disposed within the housing member and having its lines connected to the housing member, and ejector means for extending the housing member and ejecting the parachute from the upper end thereof, thereby to deploy the parachute in such a manner that the parachute lines may not snag with the rotor blades.

The invention may also be designed as a separate attachment for fastening coaxially to the upper end of the rotor shaft of a helicopter. Hence, it also consists in a safety device for attachment to a helicopter, comprising a telescopic housing unit including a mounting member adapted to be secured to the rotor shaft of the helicopter so that the unit is coaxial with the rotor shaft, and a tubular housing member slidable relative to the mounting member from a retracted position to an extended position in which the housing member projects from one end of the mounting member, a folded parachute disposed within the housing member and having its lines connected thereto, and ejector means for extending the housing member with respect to the support member and ejecting the parachute from the housing member, thereby to permit deployment of the parachute in such a manner that the parachute lines may not snag with the rotor blade of the helicopter upon which the device is installed.

The distance by which the housing member projects, when it is ejected into its extended position, must be sufficient to ensure that the parachute lines will not snag the helicopter rotor as the parachute is deployed and when open, even if the helicopter has rolled, as a result of the emergency, into a position in which the rotor blades are turning in a substantially verticai plane.

Hence, for small, say 2-seater helicopters, the housing member should project by not less than about 60 cm above the plane of rotation of the rotor blades. For larger helicopters, the projection increases proportionally to the sizes of such helicopters. In practice, the minimum requirements may be determined and set by civil aviation authorities.

The ejector means may comprise separate ejector devices for the housing member and the parachute, the ejector for the latter being arranged to operate a short interval after actuation of the housing ejector means and when the housing member is in its fully extended position.

Alternatively, the ejector means may simply act on the housing member, the acceleration achieved when the housing member engages stops in its fully extended position being used to fire the parachute from the housing. The ejector means may, for example, comprise a small explosive cartridge or charge and, in this case, by arranging a passageway between the cartridge or charge chamber on the exterior of the housing and its interior, the fired charge may also be used to assist in ejecting the parachute. In any event, latches may be provided for retaining the housing member in its fully extended position when it is fired into this position.

Preferably, a rotatable connection is provided at some position between the parachute lines and the rotor shaft or mounting member, as the case may be, so that the lines and parachute are freely rotatable with respect thereto upon deployment of the parachute.

The housing member may be slidably and rotatably mounted with respect to the rotor shaft or mounting member so as to provide the abovementioned rotatable connection between the parachute lines and the latter. Alternatively, the parachute lines may be connected to the housing member via a fastening member rotatably mounted coaxially within the housing member.

Such a fastening member may be in the form of a cannister containing the parachute and mounted within the housing member on rolling bearings.

The fastening member or cannister, preferably, has portions projecting from the end of the housing member so that, when the latter is extended, the parachute lines are prohibited from wearing against the housing, and possibly severing, upon relative rotation of the parachute and the suspended helicopter.

If the helicopter has a plurality of lift rotors a safety device according to the invention may be constructed or installed on each rotor shaft.

In order that the invention may be more readily understood, reference will now be made to the accompanying drawings, in which: Figure 1 is a diagrammatic perspective view of a helicopter rotor assembly embodying the invention, Figure 2 is an axial section through the top of the rotor shaft of Figure 1 showing the safety device installed therein, and Figure 3 is an axial section similar to Figure 1 showing the safety device actuated to deploy the parachute.

Referring to the accompanying drawings, Figure 1 shows a helicopter rotor assembly comprising three rotor blades 1 connected by lag hinges 2 to a ring member 3 mounted on a hollow rotor shaft 4 which is in turn connected to the motor (not shown) of the helicopter.

The shaft 4 is associated with a swash plate assembly 5 which is in turn connected to the blades 1 by links 6 to control the angle of attack of the blades as they rotate. The angle of tilt of the swash plate assembly 5 is controlled by a control rod 7. As the operation or the rotor assembly is entirely conventional no additional description will be given.

The safety device is disposed within the top end of the hollow rotor shaft 4. As shown in Figure 2, it comprises a cylindrical housing member 10 telescopically mounted within the rotor shaft and slidable through the top of the shaft from a retracted position, in which the housing member is wholly contained within the upper end of the rotor shaft, to an extended position (see Figure 3) in which the housing projects above the plane of rotation of the rotor blades 1 by the required distance to ensure safe deployment of the parachute, even if the helicopter is rolling so violently that the rotor blades are in a vertical plane.The housing member 10 is slidably guided within the rotor shaft by an internal annular flange 11 at the top of the rotor shaft embracing the external walls of the housing, and a base plate 12 of the housing, the peripheral portion of which forms an external flange 13 engaging the internal walls of the rotor shaft 4. The flanges 11, 12 abut in order to define the fully extended position of the housing and prevent the latter from being ejected from the shaft. The housing may be held in its extended position by suitable latches (not shown).

Disposed within the housing member 10 is a cylindrical cannister 14 which is mounted on suitable ball bearings 15 disposed between the inner wall of the housing and the cannister so that the latter is freely rotatable with respect to the housing and, hence, the rotor shaft. Internally, the cannister 14 is divided into two compartments, the upper compartment 1 6 containing a folded parachute (not shown) and the lower compartment 17 containing an ejector device or arrangement for ejecting the parachute upwardly from the cannister. The parachute lines are attached in any suitable manner to the cannister so that, when the parachute is deployed, it is connected to the rotor shaft 4 but may rotate relatively thereto.

In a modification, where the ejector device for the housing member is a small explosive cartridge or charge disposed in an ejector chamber 1 8 below the housing base plate 12, a separate ejector device need not be provided for the parachute and the lower compartment 17 of the cannister may be simply connected to the chamber 1 8 via a small passageway 1 9 so that when the charge is fired, the resulting gases also serve to assist in ejecting the parachute from the cannister 14 when the housing member is stopped in its fully extended position by engagement of the stop flanges 11, 1 3.

The housing member 10 and cannister 14 may be closed by a cap 20, for example, made from plastics material, which fits within the upper end of the rotor shaft and is ejected and released upon extension of the housing member. The cannister 14 is arranged at 21 to project slightly beyond the upper rim of the housing member 10 so that when the parachute is deployed, the parachute lines are prohibited from engaging the housing with the consequent risk of wear and severing upon relative rotation of the parachute and helicopter.

The ejector devices utilised may take a number of different forms and these may depend on the size of the helicopter. Thus, it is conceivable that the ejector may be mechanical and include a strong spring, normally compressed, but capable, on release, of instantaneously extending the housing member or firing the parachute clear of the cannister. Alternatively, the device may comprise highly compressed, non-reactive gas which, upon release, can again extend the housing member and eject the parachute in the required manner. In yet another alternative, already mentioned above, it comprises a small explosive cartridge or charge which, upon actuation by a suitable trigger mechanism explodes and fires the housing member into its extended position and/or the parachute from the cannister.

The ejector device is connected to a suitable control member or switch in the pilot's compartment so that it can be readily actuated in the event of an emergency. It may, alternatively, be connected to a suitable monitoring arrangement which automatically actuates the ejector on detection of an emergency. It will, of course, be appreciated that care must be taken to avoid unwanted actuation of the ejector during normal flight. However, when an emergency occurs, the housing ejector device is manually or automatically operated and, in sequence, the housing member 10 is instantaneously moved into its extended position, and the ejector device for the parachute, if any, is actuated to deploy or assist in deploying the parachute, or this operation may be assisted by the firing of the explosive charge used as the housing ejector. In any event, the parachute is ejected and held clear of the rotor blades by the extended housing member.

Once the parachute has been ejected from the cannister 1 4 it may be necessary to ensure that the parachute opens rapidly and correctly without having to rely solely upon any falling motion of the helicopter. Thus, the folded parachute may surround a suitable mechanism which is ejected with the folded parachute and which is arranged to be triggered after ejection so as rapidly to open the parachute. The triggering of this mechanism may be carried out by a timing device set to operate a predetermined interval after the ejection of the parachute from the cannister or by any other suitable remote control means. The mechanism may comprise a container of compressed gas, the release of which unfurls the parachute. Alternatively, it may be a mechanical device or a combination of the above.

It will, of course, be appreciated that once the parachute has been ejected it will be attached to the helicopter at a point in substantial alignment with the helicopter's centre of gravity, thus, helping to maintain the helicopter in a relatively stable attitude as it falls. In the case of engine failure, the use of the helicopter's autorotative capability in combination with the parachute will additionally decrease the speed of descent and allow a safer landing.

It will also be appreciated that the parachute may be of the "gliding" type and/or have some simple device for producing a controlled pull on the parachute lines, thereby giving the possibility of a pilot controlled descent.

In the embodiment illustrated, the safety device is housed in the hollow rotor shaft 4. Such shafts are used in large helicopters. Alternatively, larger helicopters frequently have the drive transferred to their rotors by a cage-like arrangement of tubes.

Such an arrangement embraces even greater space for the housing member and its associated components on the axis of rotation of the helicopter rotor.

Whilst a particular embodiment has been described, it will be understood that modifications can be made without departing from the scope of the invention, as defined by the appended claims.

For example, instead of a rotatably mounted cannister within the housing member, the housing member, itself, may be slidably and rotatably mounted within the rotor shaft 4. This may be achieved by the provision of suitable thrust and rotating bearings on one or both of the flanges 11, 13, which serve to provide for free rotation of the housing member in its extended position.

Furthermore, instead of the safety device being constructed within the upper end of a hollow rotor shaft, it may be formed as a separate attachment for fastening coaxially to the top of the rotor shaft.

Such an attachment may be a telescopic assembly similar to that illustrated in Figure 2, except that the rotor shaft of Figure 2 will be a mounting member suitably adapted at its lower end for fastening the assembly coaxially to the top of the rotor shaft.

In a modification, the safety device may simply comprise a tubular housing extension at the upper end of the rotor shaft and projecting the required distance beyond the plane of rotation of the rotor blades so that a folded parachute housed within the extension may be safely ejected and deployed without risk of the parachute lines snagging the helicopter rotor. The parachute may be connected to the tubular extension via a suitable rotatable connection, such as, a rotatable cannister, which permits relative rotation of the parachute and the helicopter and prohibits the parachute lines from engaging the relatively rotating extension.

Claims

1. A helicopter comprising a rotor shaft, a tubular housing member mounted within a hollow upper end of the rotor shaft and slidable through the top of the rotor shaft from a retracted position to an extended position in which the housing member projects above the plane of rotation of the rotor blades, a folded parachute disposed within the housing member and having its lines connected to the housing member, and ejector means for extending the housing member and ejected the parachute from the upper end thereof.

2. A safety device for attachment to a helicopter, comprising a telescopic housing unit including a mounting member adapted to be secured to the rotor shaft of a helicopter so that the unit is coaxial with the rotor shaft, and a tubular housing member slidable relative to the mounting member from a retracted position to an extended position in which the housing member projects from one end of the mounting member, a folded parachute disposed within the housing member and having its lines connected thereto, and ejector means for extending the housing member with respect to the support member and ejecting the parachute from the housing member.

3. A helicopter or safety device therefor as claimed in claim 1 or 2, in which the ejector means comprises separate ejector devices for the housing member and the parachute, the ejector for the latter being arranged to operate a short interval after actuation of the housing ejector means and when the housing member is in its fully extended position.

4. A helicopter or safety device therefor as claimed in claim 1 or 2, in which the ejector means acts on the housing member, the acceleration achieved when the housing member engages stops in its fully extended position being used to eject the parachute from the housing.

5. A helicopter or safety device therefor as claimed in claim 4, in which the ejector means comprises a small explosive cartridge or charge.

6. A helicopter or safety device therefor as claimed in any one of the preceding claims, in which a rotatable connection is provided at some position between the parachute lines and the rotor shaft or mounting member.

7. A helicopter or safety device therefor as claimed in claim 6, in which the housing member is slidably and rotatably mounted with respect to the rotor shaft or mounting member so as to provide the rotatable connection between the parachute lines and the latter

8. A helicopter or safety device therefor as claimed in claim 6, in which the parachute lines are connected to the housing member via a fastening member rotatably mounted coaxially within the housing member.

9. A helicopter or safety device therefor as claimed in claim 8, in which the fastening member is in the form of a cannister containing the parachute and rotatably mounted within the housing member.

10. A helicopter or safety device therefor as claimed in claim 8 or 9, in which the fastening member or cannister has portions projecting from the end of the housing member so that, when the latter is extended, the parachute lines are prohibited from engaging the housing.

11. A helicopter or safety device therefor, constructed, arranged and adapted to operate substantially as hereinbefore described with reference to the accompanying drawings.