Shell joint with an adjustable gas ejection slot

STATEMENT OF GOVERNMENT INTEREST

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

BACKGROUND OF THE INVENTION

(1) Field of the Invention

The present invention relates generally to an adjustable gas ejection slot and more particularly to a water tight shell joint for super cavitating underwater vehicles with an adjustable gas ejection slot.

(2) Description of the Prior Art

Systems for reducing the drag on a vehicle moving through a fluid by ejecting a fluid into a boundary layer adjacent the nose portion of a vehicle are known in the art. One such system is shown in U.S. Pat. No. 5,603,278 to Nedderman et al.

The forward shell of a super cavitating underwater vehicle requires three or more supplemental gas ejection slots in order to maintain a cavity over the entire vehicle. The gas flow needs to be metered in order to provide the correct amount of gas at the right location. The width of the slot needs it to be matched to the volume of gas being ejected in order to get a uniform cavity.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a shell joint for a vehicle with at least one adjustable gas ejection slot.

It is a further object of the present invention to provide a shell joint as above with at least one slot which can be adjusted to match a volume of gas which needs to be ejected in order to obtain a uniform cavity over the vehicle.

The foregoing objects are attained by the shell joint of the present invention.

In accordance with the present invention, a shell joint for use on a vehicle, particularly an underwater vehicle, is provided. The shell joint broadly comprises a female member defining a first part of at least one slot for ejecting gas, a male member defining a second part of the at least one slot, and means for adjusting the width of the at least one slot to obtain a volume of ejected gas sufficient to obtain a uniform cavity about the vehicle.

Other details of the water tight shell joint of the present invention, as well as other objects and advantages attendant thereto, are set forth in the following detailed description and the attached drawing wherein like reference numerals depict like elements.

DESCRIPTION OF THE DRAWINGS

FIG. 1

illustrates a cross section of a water tight shell joint in accordance with the present invention;

FIG. 2

illustrates a portion of the female member of the joint of FIG

1

; and

FIG. 3

illustrates a portion of the male member of the joint of FIG.

1

.

DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

The present invention relates to a water tight, annular shell joint for super cavitating water vehicles with an adjustable gas ejection slot. The forward shell of the vehicle is tapered making it more economical to machine it from short lengths of stock. A series of ejection slots are needed in this area in order to maintain a cavity over the entire vehicle. It has been found to be convenient to incorporate the ejection slots into the joint.

Referring now to

FIGS. 1-3

, a cross section of a portion of a water tight, annular shell joint

10

in accordance with the present invention is shown. As can be seen from

FIGS. 2 and 3

, the female member

12

and the male member

22

of the joint

10

are actually formed by cylindrical bodies.

As can be seen from

FIG. 1

, the female member

12

of the joint

10

contains part of a gas ejection annulus

14

. The female member

12

also includes an aft facing deflector

16

that forms a first part of a tapered slot

18

for aiming escaping gas back along the shell. A bolt flange

20

with threaded holes is provided as part of a means for securing the female member

12

to the male member

22

. An aft projection

24

on the female member

12

forms an O-ring sealing surface

25

.

The male member

22

of the joint

10

has the other part of the annulus

14

and a first forward facing protrusion

26

that forms the other part of the tapered slot

18

. The male member

22

also has a second forward facing protrusion

28

which serves as a bolt flange. As can be seen from

FIG. 1

, the protrusion

28

overlaps a portion of the sealing surface

25

and contains a groove

30

for housing an O-ring

32

to seal the joint

10

so as to make it water tight.

A gas line

34

supplies gas to the annulus

14

where it escapes through slot

18

. A typical joint

10

may have two or more gas lines depending on the diameter of the annulus

14

.

A plurality of fasteners

36

, such as bolts, are provided to join the female and male members

12

and

22

together. The number of fasteners

36

used to secure the members

12

and

22

together depends on the diameter of the joint

10

.

FIG. 1

shows the slot

18

with a minimal opening. The width of the slot

18

may be increased by inserting shims

38

into the space

40

between the flanges

20

and

28

. The shims

38

may be in the form of washers held in place by the shanks

42

of the fasteners

36

. Alternatively, the shims

38

may be large shim flanges having the same bolt pattern as the flanges

20

and

28

.

The joint

10

of the present invention solves several problems in building a tapered forward shell for a super cavitating vehicle. The forward shell can be made in short sections of different diameters of stock so less stock is used. Having the slots at the joint makes the rather complex slots and annulus easier to machine. Shimming the bolt flanges allows the slot width to be very precisely adjusted.

It is apparent that there has been provided in accordance with the present invention a shell joint with an adjustable gas ejection slot which fully satisfies the objects, means, and advantages set forth hereinbefore. While the present invention has been described in the context of specific embodiments thereof, other alternatives, modifications, and variations will become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations as fall within the broad scope of the appended claims.