Interface pallet assembly for a helicopter-based weapon system

STATEMENT OF GOVERNMENT INTEREST

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without payment of any royalties thereon or therefor.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to ordnance mounting assemblies and, more particularly, to a mounting assembly for attachment to a helicopter floor to provide a stable mount for a machine gun or other weapon system, and to increase the weapon system's field of fire by positioning all or most of the weapon system outside of the helicopter's cabin.

2. Description of the Background

The utility of a weapon system is largely proportional to the extent of its field of fire. The field of fire can be limited by certain physical attributes of the system itself, for example, the manner in which it is mounted or supported, and/or the type of vehicle used to transport the weapon system. One vehicle that introduces significant limitations is the helicopter. The field of fire for a helicopter-based weapon system is severely limited by the presence of the main rotor overhead and the secondary rotor positioned on the tail. Thus, the field of fire is primarily directed downward and/or forward. Moreover, if the weapon system is mounted within the helicopter's cabin it may experience additional limitations on its field of fire due to the dimensions of the opening through which it is fired.

The challenge of maximizing the effective field of fire of a helicopter-based weapon system therefore became an issue of positioning all or most of the device outside of the helicopter's cabin. The present inventor is not the first to devise means for mounting a weapon system external to a helicopter's cabin.

There are several examples in this regard.

For example, U.S. Pat. No. 5,421,239 to Sanderson discloses an aircraft armament mounting system that includes an elongated support plank member which is longitudinally insertable transversely through the aircraft cabin area so that a central portion of the plank is disposed within the cabin area with opposite end portions of the plank projecting outwardly from the aircraft. The central plank portion is suitably anchored within the cabin area, and the outwardly projecting plank end portions are configured to removably support machine guns supplied with belted ammunition from magazine boxes secured to the top side of the central plank portion within the cabin area.

U.S. Pat. No. 5,767,436 to Sanderson et al. discloses an elongated support plank structure that longitudinally extends transversely through the cabin area of a helicopter and has outer end portions projecting outwardly beyond opposite sides of the helicopter. A pair of 30 mm. machine guns are mounted on the plank end portions and are supplied with belted ammunition from magazine boxes mounted on the plank within the cabin area. The 30 mm. machine guns are secured to the outer plank end portions by specially designed mounting structures each having a cradle portion with axis-adjustable roller assemblies that engage the gun and essentially preclude lateral movement thereof relative to the cradle, but permit roller-guided longitudinal gun recoil movement, during firing of the gun. The field of fire provided by this mounting structure is fixed essentially forward in the direction of the helicopter's flight path, and the lightweight, M230 30 mm. machine guns do not possess the same capabilities (e.g. firepower) of larger, heavier MK44 systems.

U.S. Pat. No. 6,250,197 to Sanderson discloses a machine gun and associated armament apparatus including an ammunition box for supplying belted ammunition to the gun. The gun and associated apparatus are exteriorly supported on a landing gear sponson tow plate of a helicopter, adjacent a cabin area gunner's window, using a specially designed pintle support structure. The external mounting of the gun and associated armament apparatus frees up cabin space and permits the gunner's window to be closed with the gun in a ready position.

While each of the prior art devices detailed above provides an ability to mount all or most of a weapon system outside of a helicopter's cabin, thereby increasing the weapon's field of fire, they are meant to accommodate only relatively small, lightweight weapon systems (e.g. small caliber machine guns, weapons not requiring mounting turrets). The installation of larger, heavier weapon systems (e.g. chain guns with stabilized turret systems) in a helicopter raises the additional issue of preserving the in-flight stability of the aircraft. To the best of the knowledge of the present inventor, a mounting assembly (i.e. an interface pallet) for positioning all or most of a large, heavy weapon system external to a helicopter's cabin does not exist.

It would, therefore, be greatly advantageous to provide an interface pallet assembly that, in addition to positioning all or most of a weapon system outside of the helicopter's cabin, in order to increase its field of fire, is designed to accommodate a large, heavy weapon inclusive of a stabilized turret. An apparatus for this purpose must preserve the in-flight stability of the aircraft. It should also utilize existing points of connection to the helicopter's deck, be fabricated of materials with high strength-to-weight ratios, and provide a storage or mounting location for accessories associated with the weapon system.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide an interface pallet assembly for positioning all or most of a large, heavy weapon system external to a helicopter's cabin in order to increase its field of fire.

It is another object of the present invention to provide an improved interface pallet assembly that extends a helicopter-based weapon system's downwardly-angled field of fire without negatively impacting its azimuth rotation capability, thereby allowing the weapon system to be used for helicopter-based airborne mine clearance missions.

Yet another object of the present invention is to provide an improved interface pallet assembly that preserves the in-flight stability of the helicopter by equally distributing the forces associated with the weight and recoil of the weapon system to the deck of the aircraft.

It is still another object of the present invention to provide an improved interface pallet assembly that is fabricated of materials with high strength-to-weight ratios so as to not unduly add to the overall weight of the helicopter and its payload.

It is another object of the present invention is to provide an improved interface pallet assembly as described above that attaches to existing points of connection on the helicopter's deck.

Still another object of the present invention is to provide an improved interface pallet assembly that includes storage or mounting locations for accessories associated with the weapon system (e.g. ammunition canisters, batteries).

According to the present invention, the above-described and other objects are accomplished by an interface pallet assembly for use between the cabin deck of a helicopter (e.g. the MH60S helicopter) and a large, heavy weapon system (e.g. the stabilized turret system and deck-mounted MK44 30 mm. chain gun). The present invention generally incorporates a platform including a cantilevered pallet mounted inside the helicopter and extending downward at an angle to a turret plate external to one side of the helicopter's cabin, to which the weapon system's stabilized turret is attached. In addition, a truss assembly maintains appropriate ground clearance while supporting the platform. The one-sided design of the present invention allows the other side of the helicopter's cabin to be utilized for activities such as search and rescue missions (i.e. the deployment of a winch to lift/lower personnel, equipment, and/or supplies to/from the helicopter).

The existing deck connection points (e.g. five cargo tie-down locations in the MH60S helicopter) are utilized to secure the interface pallet assembly to the cabin deck. The five-point connection pattern between the interface pallet assembly and the MH60S helicopter deck maintains the overall balance of the airframe by providing for the even distribution of the weight and recoil forces associated with the MK 44 weapon system (i.e. a maximum load of 15,000 pounds at any single tie-down location). The interface pallet assembly adds 20E to the downward angle of fire of the weapon system and also provides for azimuth rotation of 180E. The present invention possesses a significant degree of rotational stiffness (i.e. 250,000-480,000 Newton-meters/radian, depending upon the materials of construction). Sufficient rotational stiffness is required by the aforementioned turret stabilization system to maintain the firing accuracy of the MK 44's full impulse round during burst mode firing sequences. The interface pallet assembly is fabricated of a variety of materials with high strength-to-weight ratios so as to not unduly add to the overall weight of the helicopter and its payload, and provides storage or mounting locations for a 200-round ammunition container and the battery system that powers the turret and weapon system.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features, and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments and certain modifications thereof when taken together with the accompanying drawings in which:

FIG. 1

is an isometric view of an interface pallet assembly

20

according to the present invention.

FIG. 2

is a side perspective view of the interface pallet assembly

20

of FIG.

1

.

FIG. 3

is a top perspective view of the interface pallet assembly

20

of

FIGS. 1 and 2

.

FIG. 4

is an isometric view of the interface pallet assembly

20

of

FIGS. 1-3

showing the manner in which the weapon system

50

is attached to it.

FIG. 5

is a side perspective view of a helicopter

100

showing the interface pallet assembly

20

of

FIGS. 1-3

mounted to the cabin deck

110

.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1

is an isometric view of an interface pallet assembly

20

according to the present invention.

FIGS. 2 and 3

are, respectively side and top perspective views of the interface pallet assembly

20

. The interface pallet assembly

20

generally comprises a pallet

22

joined to a turret plate

24

at a downward angle, and a pair of supporting truss assemblies connected between the pallet

22

and turret plate

24

. Each of the truss assemblies has an angle greater than that of the pallet

22

and turret plate

24

to increase the structural rigidity thereof.

Each truss assembly comprises a front tee section

32

attached at one end to the pallet

22

, and a rear tee section

34

attached at one end to the turret plate

24

and at the other end to the front tee section

32

. In addition, a post

30

is attached between the junction of the front and rear tee sections

32

,

34

to the pallet

22

. Two band aid plates

26

are also provided for increased strength, two devises

38

are provided for connecting the rear tee sections

34

to the pallet

22

, and two splice supports

36

connect the front and rear tee sections

34

,

43

together. The foregoing components create a movable platform that positions the weapon system substantially out of the helicopter cabin, adds 20E to the downward angle of fire, and also provides for azimuth rotation of 180E. Moreover, the interface pallet assembly

20

attaches at the existing deck connection points (e.g. five cargo tie-down locations in the MH60S helicopter) to secure the interface pallet assembly to the cabin deck.

The pallet

22

, turret plate

24

, and band aid plates

26

are preferably fabricated of sections of rigid, commercially available materials (e.g. type 7075 aluminum, various polymer or metal matrix composites).

The pallet

22

includes one or more cut-outs

41

,

42

that assist in directing the load path and in reducing the overall weight of the pallet

22

without compromising its structural integrity. The cut-outs

41

may also provide mounting locations for certain accessories (discussed below) associated with the weapon system

50

shown in FIG.

4

.

The pallet

22

also includes a plurality of clearance holes

43

utilized to attach the interface pallet assembly

20

to the connection points (e.g. tie-downs) located on the helicopter's cabin deck. There are two of these clearance holes

43

at the back of the pallet

22

, and three evenly-spaced holes

43

across the front. This five-point connection pattern between the interface pallet assembly and the MH60S helicopter deck maintains the overall balance of the airframe by providing for the even distribution of the weight and recoil forces associated with the MK 44 weapon system (i.e. a maximum load of 15,000 pounds at any single tie-down location).

The turret plate

24

includes a cut-out

44

that generally conforms to the base of the turret

52

(see

FIG. 4

) of the weapon system

50

. In addition to reducing the overall weight of the plate

24

, without compromising its structural integrity, the cut-out

44

also provides access to the weapon system

50

from below. The band aid plates

26

are bent longitudinally, at its transverse midpoint, to an angle of 20E.

The support posts

30

are preferably fabricated of lengths of rigid, commercially available, aluminum round stock (e.g. 6″ diameter type 2024 or 7075). The front and rear tees

32

,

34

, respectively, are preferably machined from lengths of rigid, commercially available materials (e.g. type 4140 steel plate for front tees

32

, type 7075 aluminum plate for rear tees

34

). Finally, the splice supports

36

and devises

38

are machined components preferably fabricated of lengths of rigid, commercially available, type 7075 aluminum that vary in size.

As seen in

FIG. 2

, the pallet

22

also includes areas where certain accessories associated with the weapon system

50

, such as an ammunition canister

54

or batteries

56

utilized during its operation, may be mounted.

The above-described components of the interface pallet assembly

20

according to the present invention are assembled as follows. Each of the fixed attachments disclosed herein may be, for example, a bolted or riveted connection.

A transverse edge of the pallet

22

is fixedly attached, along its top and bottom surfaces, to longitudinal edges of the band aid plates

26

. The opposite longitudinal edges of the band aid plates

26

are fixedly attached to the top and bottom surfaces of the turret plate

24

along a transverse edge. Each of the longitudinal edges of the turret plate

24

are fixedly attached to a longitudinal edge of one of the front tees

32

. The base end of each support post

30

is fixedly attached to the pallet

22

at specified locations. Each splice support

36

is fixedly attached to the distal end of a support post

30

. Each clevis

38

is fixedly attached to the pallet

22

at specified locations along its transverse edge opposite that connected to the band aid plates

26

. Each of the front tees

32

are fixedly attached at one end to an edge of the support plate

24

, and at the other end to a pair of splice supports

36

. Each of the rear tees

34

are fixedly attached at one end to a pair of splice supports

36

, and at the other end to a clevis

38

.

FIG. 4

shows the manner in which a weapon system

50

attaches to the interface pallet assembly

20

of

FIGS. 1-3

.

FIG. 5

is a side perspective view of a helicopter

100

with the interface pallet assembly

20

of

FIGS. 1-3

mounted on the cabin deck

110

. The interface pallet assembly

20

may be fabricated of a variety of materials with high strength-to-weight ratios so as to not unduly add to the overall weight of the helicopter

100

and its payload.

With combined reference to

FIGS. 1-5

, once the interface pallet assembly

20

is completely assembled, it may be mounted on the cabin deck

110

of a helicopter

100

such that the turret plate

24

extends out of the cabin through an opening in the side of the aircraft

100

. The plurality of clearance holes

43

present in the pallet

22

are utilized to fixedly attach the interface pallet assembly

20

to a corresponding plurality of pre-existing connection points (not shown in the Figures) located on the deck

110

.

The weapon system

50

that the interface pallet assembly

20

is designed to accommodate may then be installed. The turret

52

is fixedly attached to the turret plate

24

, positioning most, if not all, of the weapon system

50

outside of the cabin of the helicopter

100

. Any desired accessories associated with the weapon system

50

such as an ammunition canister

54

or batteries

56

are then mounted on designated areas of the pallet

22

. The aforesaid configuration of the interface pallet assembly

20

serves to evenly distribute the load, or forces, generated by the weight of the weapon system

50

and its recoil during operation across the plurality of preexisting connection points located on the deck

110

of the helicopter

100

. An even distribution, across the deck, of the load, or forces, associated with the presence and operation of an on-board weapon system

50

is critical to preserving the in-flight stability of the helicopter

100

The positioning of the weapon system

50

external to the cabin of the helicopter

100

on a cantilevered plate

24

(angled downward 20E) serves to widen the field of fire below the aircraft

100

while maintaining an azimuth rotation capability of 180E. This allows the weapon system

50

to fire at a greater range of surface-based targets while the helicopter

100

maintains a level flight path. For example, the additional downward firing capability created by the present invention has been demonstrated to be very beneficial for mine clearing purposes.

Having now fully set forth the preferred embodiments and certain modifications of the concept underlying the present invention, various other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with said underlying concept. It is to be understood, therefore, that the invention may be practiced otherwise than as specifically set forth in the appended claims.