Description:Field of Invention

The present invention relates to development of Helicopter Connecting Gear (HCG) for Advanced Light Helicopters (ALH) towards integration with drive system of rail less helicopter traversing system installed on-board Indian Navy and Indian Coast Guard Ships. GRSE as equipment supplier of rail less helicopter traversing system can provide now customers with a helicopter connecting gear (HCG) for undertaking helicopter traversing of ALH on-board Naval Ships. The challenge lay in providing an ergonomically designed equipment being connected to the hard points of the helicopter being sufficiently sturdy and adjustable to dimensional tolerances of air frames and air pressure on tyres.

Background Art
Three number of Indian Naval ships and six number of Indian Coast Guard ships are fitted with winch wire rail less helicopter traversing system supplied by GRSE in technical collaboration with MacTaggart Scott, UK who are pioneers and world leaders in manufacture and supply of winch wire rail less helicopter traversing systems. The equipment have been successfully installed and have undergone trials with mock- ups as helicopters are not available during trial programme of the ships. However, the equipment cannot be used at sea without a proven HCG. GRSE had earlier undertaken trials with ALH helicopter on-board INS Kamorta at harbour but could not proceed to sea due to non-availability of a proven, reliable and acceptable HCG.

In the prior art an US specification US2826431A discloses a towing device which can be attached to the wheel of the helicopter and to a towing vehicle which will act accurately to guide the helicopter in the path of the towing vehicle. It is independently traversed without drive mechanism of the helicopter.

In the prior art, a Canadian Patent No. 781,808 discloses a helicopter rapid securing system is disclosed employing a constant tension winch used to maintain the tension in the cable securing the airborne helicopter to the ship and a frame surrounding the fairlead through which the cable extends below deck, supporting two parallel arresting rails for firing towards one another from opposite sides to the frame to capture the probe of the helicopter securing the cable to the helicopter when the helicopter has landed to secure the helicopter to the deck. Thereafter, the frame is withdrawn along the track traversing the Sea King helicopter to the hangar.

In another prior art U.S. Patent No. 3.659.813 discloses the use of a trolley to which a helicopter is secured for traversing once on the deck of a ship. The trolley is displaceable along a worm gear mounted on the cross strut driven in a linear path by a drive mechanism. However, this system cannot be used to rapidly secure the helicopter on landing. It is merely a type of traversing device.

In another prior art U.S. Patent No. 4.319.722 discloses a helicopter rapid securing and traversing system for securing a helicopter on landing on the deck of a ship or subsequently traversing it from its landing position, said system comprising a housing reciprocal from a position remote from the landing area to a position adjacent the landing area of the helicopter, means for a reciprocating housing towards and away from the landing area, a carrier on the housing extending across the housing and carrying securing means thereon for securing the housing to a probe or projection on the helicopter, the carrier being moved laterally along the carrier across the housing.

Object of Invention

It is therefore an object of this invention to provide a helicopter securing and traversing system complete with components and sub-assemblies which can overcome the aforementioned difficulties with the prior systems and which can be used to reliably and safely connect to the strong points of the ALH without making any changes to the helicopter within a very short time (less than 5 min) without damaging any component of the helicopter.

Further object of the present invention is to provide a design compatible upon structural integration with the helicopter considering ship’s motion dynamics.

To fulfil the objective and manifest the operability of the HCG with minimal human intervention without making any changes on the helicopter strong points. The equipment is simple to use, easy to engage, easily dismantle with rollers to easily push the items and store them in the compact spaces of the helo deck.

Further and other objects of the invention will be realized by those skilled in the art and from the following summary of the invention and detailed description of preferred embodiments thereof.

Summary of invention
The innovation relates to a hook-on arrangement which can be connected to the strong points of the ALH without making any changes to the helicopter. The item is required to be of robust construction meeting requirement of handling helicopter safely in adverse sea conditions upto sea state 5.

According to the present invention there are two appendages The NLG (Nose landing gear) Steering Arm has a slot in which a large bow shackle is configured to move along the slotted path to cater to off-centric landing of the NLG which can be swivelled manually to suit the traverse. In order to integrate the Steering Arm fabrication with the handle of the operator two sections of the handle lower part and handle fabrication have been connected with quick release pins. The entire structure can be moved on the deck on heavy duty castor rollers in idle condition of the helicopter. In order to cater to different vertical heights of the structure a spindle assembly has been provided. The final engagements of the helicopter to the steering arm is done by pushing the interface pin inside the hollow axle of the helicopter nose wheel and lock the same using quick release pin.

Therefore such as herein described there is provided A Helicopter Connecting Gear for Rail Less Helicopter Traversing System comprising of a Steering Arm fabrication (1) structure suitable for the interfaces and protrusions of the helicopter, a body including a slot in which a large bow shackle (4) is configured to move along the slotted path to cater to off-centric position of the NLG (Nose Landing Gear) is swivelled in order to suit the traverse, a handle integrated with the said Steering Arm fabrication including two sections namely handle lower part (2) and handle fabrication (3) operatively connected with quick release pins (7), a plurality of heavy duty castor rollers configured to move the entire structure on the deck (6); and a structured a spindle assembly (8) with connecting pipes is configured to cater the different vertical heights of said traversing system; wherein the engagement of the helicopter to the Steering arm is carried out by pushing the interface pin (5) inside the hollow axle of the helicopter nose wheel and lock the same using quick release pin.

The aft of the helicopter has two MLGs which are provided with two lugs for the purpose of towing. The MLG engaging fork engages to the MLG lug of the helicopter of the L bracket and using a boss and a quick release pin is inserted inside the MLG lug and is locked from both the port and the starboard sides of the ALH helicopter. A crossbar is engaged to the lug of the L bracket on opposite sides of the L bracket. This integrates all the structural members into one unit. After this engagement is completed, all the height adjustable wheels are lifted to allow for system pull by the rail less HTS

Brief Description with the Accompanying Drawings

Fig 1 illustrates a plan and elevation of Steering Arm for ALH for connecting to the ALH NLG in accordance with the present invention;

Figure 2 illustrates plan and elevation of MLG aft fixing arrangement for connecting to the MLG of the ALH showing details of the items therein in accordance with the present invention.

Detailed Description with Accompanying Drawings

There are two different items which constitute a helicopter connecting gear for advanced light helicopter manufactured by M/s HAL. Those are – Aft Fixing Arrangement and a Steering Arm. With reference to Figure 1, the steering Arm comprises of the principal items as tabled above. The Steering Arm fabrication (1) is a geometrically designed structure suitable for the helicopter considering the interfaces and protrusions of the helicopter. The body has a slot in which a large bow shackle (4) can move along the slotted path to cater to off-centric position of the NLG which can be swivelled manually to suit the traverse. In order to integrate the Steering Arm fabrication with the handle of the operator the two sections of the handle lower part (2) and handle fabrication (3) have been connected with quick release pins (7). The entire structure can be moved on the deck on heavy duty castor rollers (6). In order to cater to different vertical heights of the structure a spindle assembly (8) has been provided. The final engagement of the helicopter to the Steering arm is done by pushing the interface pin (5) inside the hollow axle of the helicopter nose wheel and locks the same using quick release pin.

Table 1(List of Items)
Item No Name of Item Item No Name of Item
1 Steering Bar Fabrication 5 Interface Pin
2 Handle (Lower Part) 6 Heavy Duty Castor Roller
3 Handle (Fabrication) 7 Quick Release Pin
4 Large Bow Shackle 8 Spindle Assembly

As shown in Fig 2, the aft of the helicopter has two MLGs (Main Landing Gear) which are provided with two lugs for the purpose of towing. The MLG engaging fork (1&4) engages to the MLG lug of the helicopter of the L (8) bracket and using a boss, a quick release pin (6) is inserted inside the MLG lug and is locked from both the port and the starboard sides of the ALH helicopter. A crossbar (2) is engaged to the lug of the L bracket (8) on opposite sides of the L bracket (8). This integrates all the structural members into one unit. After this engagement is completed, all the height adjustable wheels are lifted to allow for system pull by the rail less HTS.
Table 2(List of Items)
Item No Name of Item Item No Name of Item
1 MLG Engaging Fork (Port) 5 Turn Buckle Arrangement
2 Crossbar 6 Quick Release Pin (MLG)
3 Adjustable Castor Roller 7 Quick Release Pin (Crossbar)
4 MLG Engaging Fork (Stbd) 8 L bracket

In an exemplary embodiment, the material of the aft steering arm for helicopter connecting gear is SAILMA 350 High tensile steel except for spindle castor which are of AISI 316 and connecting pipes of EN 24(H&T).

Further, the Steering Arm is essentially of structural steel SAILMA 350 for the main body and Aluminium alloy 6082 T6 as handle.

SAILMA
Grade C max Mn max S max P max Al min Si max CE max MAE max
350 0.20 1.55 0.045 0.045 0.02 0.45 0.46 0.25
350 HI 0.20 1.55 0.040 0.040 0.02 1.45 0.45 0.25

The brief operating conditions are as under:-

(a) Sea condition upto sea state 5
(b) Operating capabilities towards traverse in sea states which produce a motion of Roll of+20 degree, pitching of +5 degree, yaw of 10 degree.
(c) Athwart ship wind speed of 40 Knots, Heave of+2 metres.
(d) Vertical & Horizontal Acceleration of 0.25g

Accordingly, the structural items have undergone finite element analysis and have been found suitable for towing forces up to 50% in excess of the imminent forces on account of ships motion and effects of acceleration. The item is intended for use on-board naval ships specific to systems where winch wire rail less helicopter traversing systems are fitted.

Advantages & Uses of the Invention

(a) Deployment of rail less helicopter traversing system with ALH on-board Naval and Coast Guard ships.
(b) Compact individual units/sub-assemblies fitted with castor roller wheels which can be easily integrated into complete units upon requirement considering minimum space availability of the ship.
(c) Can cater to actual ground conditions in which there is mechanism of engagement to the system even if the strong points of the helicopter would otherwise require modifications.

Inventive step
Design and manufacture of a prototype HCG for connecting the item to the strong points of the ALH for the purpose of traversing ALH using winch wire auto tensioning rail less helicopter traversing system.

Fitment Trials of the equipment have been completed apart from Load Testing in presence of Internal Accredited Classification Society, namely IRS. Apart from the fitment trials, the HCG had been connected to actual ALH on-board INS Kamorta at Kochi in harbour and the trials were successful.

The HCG is ergonomically designed suitable for handling within the stipulated time of preferably 4 minutes by a single person and is acceptable to the user.

Industrial Application
With the invention of the HCG for ALH the customers can now plan search and rescue (SAR) operations from the ships using ALH which is a long standing requirement. This will alleviate concerns of the customers towards handling of ALH for the systems now fitted with rail less help traversing systems. Also, upon completion of sea trials, faith and belief of the customers will be instilled and business prospects on retro-fitment on different war ship platforms presently fitted with other systems can be exploited.

TEST RESULTS
The herein disclosed gear upon manufacture has been load tested and witnessed by International Accredited Classification Society (IACS) – IRS and has been tested for fitment by the end user on actual helicopter by aviation authorities of Indian Navy who have recorded time of engagement of the helicopter connecting gear as 04 minutes which is in line with their requirements.

GRSE undertook FEA of Aft Fixing Arrangement model and the report was sent to MTS for vetting. As suggested, GRSE adopted a ‘minimum constraint approach’ and repeated the analysis with the bore on the starboard side fully constrained but applied a reactive force to the port side quick release pin location point. This approach will allow the arm to flex naturally and provide more accurate results in the areas of concern. The deflection plots are not presented in this document as the minimum constraint approach is aimed at bringing out maximum possible stress by invoking boundary conditions in which only z direction has been constrained.

Minimum Constraint Approach:

1.1 REACTION FORCES AS FOLLOWS :
Boundary Conditions Displacement Rotation
All Load Cases X Y Z X Y Z
AFT Fixing Arrangement IWO Quick Release Pin for ALH Wheel. Free Free Fix Free Free Free

The maximum force observed on the QRP is 3.694 N and the pin used in this arrangement will withstand double shear resistance of 257 kN which is is much in excess of the applied loads. Hence, the pins are safe for exploitation.

The actual trials with live ALH was conducted on-board INS Kamorta at Kochi and were successfully demonstrated to the authorised test pilot.

Descritpion Reference Reading at no load (in mm)
(A) Reading at static load (in mm)
(B) Reading when
load is released
(C) Permanent Set (in mm)
(C – A) Remarks
Handle (Lower Part 550 556 550 0
90 degree port
458 462 458 0
500 509 500 0
550 555 550 0
90 degree starboard
458 461 458 0
500 510 500 0

Note : These dimension to be checked after removing the item from the Quick Release
Pin.

LOAD TEST FOR AFT FIXING ARRANGEMENT :
a) Load of 1,875 kgs. has been applied to the Bracket Fabrication at mock up centre line for 5 minutes. SAT / UNSAT

b) Load of 1,875 kgs. has been applied to the Bracket Fabrication @ 45-DEGREE angle mock up centre line for 5 minutes. SAT / UNSAT

c) Load of 1,875 kgs. has been applied to the Aft Fixing Arrangement at mock up centre line for 5 minutes. SAT / UNSAT

d) Load of 1,875 kgs. has been applied to the Aft Fixing Arrangement @ 45-degree angle mock up centre line for 5 minutes. SAT / UNSAT

e) VI & DI checks for deflection have been carried after release load, if any as per given table.

Description Reference reading at no load (in mm) (A) Reading at static load (in mm) (B) Reading when load is released (C) Permanent set
(in mm)
(C – A) Remarks
ASSLY OF AFT FIXING ARRANGEMENT (Port) 475 478 475 0 Straight Pull
200.5 204 200.5 0
1749 1753 1749 0
ASSLY OF AFT FIXING ARRANGEMENT (Stbd) 475 478 475 0
200.5 204 200.5 0
1749 1753 1749 0
ASSLY OF AFT FIXING ARRANGEMENT (Port) 475 476 475 0 45 degree pull at port side
200.5 203 200.5 0
1749 1752 1749 0
ASSLY OF AFT FIXING ARRANGEMENT (Stbd) 475 477 475 0
200.5 204 200.5 0
1749 1754 1749 0
ASSLY OF AFT FIXING ARRANGEMENT (Port) 475 476 475 0 45 degree pull at port side
200.5 203 200.5 0
1749 1752 1749 0
ASSLY OF AFT FIXING ARRANGEMENT (Stbd) 475 477 475 0
200.5 204 200.5 0
1749 1754 1749 0

Numerous characteristics and advantages of the invention covered by this document will be set forth in the foregoing description. It will be understood, however, that this disclosure is, in many aspects, only illustrative. Changes may be made in details, particularly in matters of shape, size and arrangement of parts without exceeding the scope of invention.

Claims:1. A helicopter connecting gear for rail less helicopter traversing system comprising of :
a Steering Arm fabrication (1) structure suitable for the interfaces and protrusions of the helicopter;
a body including a slot in which a large bow shackle (4) is configured to move along the slotted path to cater to off-centric position of the NLG (Nose Landing Gear) is swivelled in order to suit the traverse;
a handle integrated with the said Steering Arm fabrication including two sections namely handle lower part (2) and handle fabrication (3) operatively connected with quick release pins (7);
a plurality of heavy duty castor rollers configured to move the entire structure on the deck (6); and
a structured a spindle assembly (8) with connecting pipes is configured to cater the different vertical heights of said traversing system; wherein the engagement of the helicopter to the Steering arm is carried out by pushing the interface pin (5) inside the hollow axle of the helicopter nose wheel and lock the same using quick release pin.

2. The helicopter connecting gear for rail less helicopter traversing system as claimed in claim 1, wherein
a pair of MLG engaging fork (1&4) adapted for engaging to the two MLG lugs of the helicopter and a L- bracket (8) using a boss;
a quick release pin (6) inserted inside the MLG lug and is locked from both the port and the starboard sides of the said helicopter;
a crossbar (2) engaged to the said lug of the L-bracket (8) on opposite sides of the said L- bracket (8), which integrates all the structural members into one unit; and
a plurality of height adjustable wheels, which are lifted in order to allow for said system pull by the rail less HTS.

3. The helicopter connecting gear for rail less helicopter traversing system as claimed in claim 1, wherein the said structural items are configured for towing forces up to 50% in excess of the imminent forces on account of ships motion and effects of acceleration.

4. The helicopter connecting gear for rail less helicopter traversing system as claimed in claim 1, wherein the material of the aft steering arm for helicopter connecting gear is SAILMA 350.

5. The helicopter connecting gear for rail less helicopter traversing system as claimed in claim 1, wherein the spindle castor is made from AISI 316 steel and connecting structure of EN 24 (H&T).

6. The helicopter connecting gear for rail less helicopter traversing system as claimed in claim 1, wherein the said handle is made from Aluminium alloy 6082 T6.

7. The helicopter connecting gear for rail less helicopter traversing system as claimed in claim 1, wherein the said gear is made suitable for handling within the stipulated time of preferably 4 minutes by a single person.