DISTRIBUTED SLIDING RAILS OF THE HELICOPTER CABIN DOOR ON A CURVED AIRFRAME

Background of the Invention

Majority of the helicopters consists of the slid-able cabin doors due to its size, ease of maintenance and the operability. On a curved airframe it is difficult to provide the same, since sliding channel required to be straight. As Light Utility Helicopter (LUH) is 3 ton class helicopter which in turn a smaller fuselage with smaller cabin and the curved surface ahead and behind the door\ Though the cabin is small, for the door it is important to provide as possible as wider entrance to ease egress in emergency events like rescue and slithering operations. This was a driving factor to arrive an optimum solution to enable the sliding door installation on to the LUH. On the other hand, associated components of the installation must be submerged into the air frame so that the resulting drag also possibly low.

Summary of the Invention
The invention described here under consist of a new type of provision for sliding channels for
the door in a constrained environment. This is by providing distributed sliding rails to overcome the curved surface constraint. This document consists of such two schemes which can be further selected based on the detailed design and structural integrity requirements.

Method 1
The components involved and their arrangement is shown in Figure 1. The fulcrum (3) slides in the channel fixed (1) on the airframe. Another fulcrum (4) is mounted on to a bar (2) which moves in the fixed channel (1). The door (5) is installed through the both fulcrums (3) and (4) into the sliding system on the airframe structure. Figure 2 shows the components of the scheme 1 in the opening position.

Method 2
The components involved and their arrangement is shown in Figure 3. The fulcrums (8) and (9) slides in the channel fixed (6) on the airframe. Other end of the fulcrums (4) is mounted in to the channels provided on the door (5). This enables the door to slid half the distance in the

channels (8) and (9) on the door and the remaining distance in the channel (6) on the airframe structure. Figure 4 shows the components of scheme 2 in the opening position.

DISTRIBUTED SLIDING RAILS OF THE HELICOPTER CABIN DOOR ON A CURVED AIRFRAME
Claims of the present Invention

1. Distributed sliding rails of the helicopter cabin door; consists two or more channels to slide the door for opening and closing with adequate number of cranks and hinges.

2. Distributed sliding rails mechanism as said in claim 1, having two or more number of sliding splits.

3. Having the sliding channel(s) on the door.

4. Having the sliding channel(s) on the door and on the airframe in combination.

5. Using the said method for helicopter door installation.