Spinning RAM air decelerator

The present invention relates to a new and unique structure in a collapsible decelerator for aerial bodies launched from a high velocity vehicle and designed to provide a high drag stabilizer capable of withstanding release in air stream velocities from subsonic to supersonic. The decelerator preferably includes a hollow inflatable star, the outermost points of which have hooded valve openings through which regulated airflow enters and inflates the star to decelerate the body to which it is attached. The new and unique capability comprises an angular offset of each air scoop to create desired rotational speed in the selected direction. The amount of angular offset and protrusion into the air stream controls the magnitude of spin rate, the direction of angular offset controls the direction of spin.

FIELD OF THE INVENTION 
This invention relates to inflatable decelerators for deployment of bodies 
launched from low and high velocity vehicles. 
BACKGROUND OF THE INVENTION 
When a speed retarding mechanism or decelerator and a body suspended 
therefrom are launched from an aircraft, dispenser or missile at high 
speed, deployment of such decelerator may cause a severe shock due to the 
sudden deceleration. A collapsible decelerating mechanism such as the one 
taught in U.S. Pat. No. 4,565,341, issued to the present inventor, 
provides many advantages over prior art speed retarding mechanisms. The 
inflatable decelerator described therein permits successful deployment at 
speeds from subsonic to supersonic, assures proper and fast inflation, and 
retains structural integrity. Following deployment, the decelerator 
provides deceleration and stabilization for the suspended body. The 
decelerator, from the moment of deployment and full inflation, functions 
also as a very efficient means of despinning the suspended body. It is, 
however, highly desirable for certain launched or dispensed bodies to 
retain spin or to be spun-up following deployment of the decelerator. Spin 
is not attainable with prior art designs. 
The present invention addresses the need in the art for spin of 
aerially-released bodies. 
SUMMARY OF THE INVENTION 
The present invention pertains to a new and unique capability in the 
deployment of aerially-released bodies not present in U.S. Pat. No. 
4,565,341. 
A decelerator according to the present invention comprises a hollow 
inflatable star-shaped body, the outermost points of which have hooded 
valve openings through which regulated airflow enters and inflates the 
star-shaped body to decelerate the body to which it is attached. 
The new and unique structure comprises angularly offsetting each hood in 
the direction of desired spin. The angular offset is provided so that a 
side force is developed at each lobe during descent of a suspended body, 
the side force causing rotation of the suspended body. 
The amount of the angular offset as well as the protrusion of each hood 
into the air stream controls the magnitude of spin. The direction of 
angular offset of each hood controls the direction of spin, clockwise, or 
counter-clockwise. 
Further objects and advantages of the present invention will become 
apparent from the following detailed description of the preferred 
embodiment.

DETAILED DESCRIPTION OF THE INVENTION 
Referring to the drawings, in FIG. 1, the decelerator 10 may be seen to 
have a shape analogous to a flat star illustratively having three radially 
symmetric outwardly projecting lobes 11. The star-shaped decelerator 10 is 
constructed by joining a flat top panel 12 to a bottom panel 13 which is 
slightly larger in area, but has an equal perimeter to panel 12. Panels 12 
and 13 are joined about their respective peripheries by continuous 
stitching in the manner suggested by seam 14 coextensive with the outer 
distal edges of both panels. Panel 13 contains sufficient material so as 
to form a slightly conical shape when chamber 10 is fully inflated. This 
shape is illustrate in FIG. 3 wherein upper top panel 12 is substantially 
flat or planar, while bottom panel 13 provides greater depth at the center 
of chamber 10 than at the outer extremities of the lobes 11. Each of the 
lobes 11 is an elongate inflatable compartment contiguous with the axial 
center portion of chamber 10. 
Attachment of the chamber 10 to body 15 is done by the use of inner plate 
16 having a swedged miniature clinch-nut 31 cemented to the inside of 
lower panel 13, while outer plate 17 is cemented to the outside of panel 
13. The inner plate 16 and the outer plate 17 are also secured to each 
other by a plurality of rivets such as 4 equidistantly spaced rivets of 
the type shown, rivets 18. Both inner and outer plates 16 and 17 may be of 
any other design having provisions to attach to a body, and they comprise 
mounting assembly 25 shown in FIG. 2. 
Of critical importance to the invention is the addition of at least one 
hole proximate to the outer distal edge of each lobe 11 as shown 
illustratively by hole 19 in FIG. 1. It is through the three holes thus 
formed that airflow necessary for inflation of chamber 10 occurs. Since 
the launch speed is based upon the operating characteristics of the 
aircraft, dispenser or missile from which it is launched, the airflow rate 
into chamber 10 can be adjusted according to the size of holes 19 in the 
lobes 11. 
Also of importance to the aerodynamics of the preferred embodiment, along 
with the star-like shape of chamber 10, is the use of scuppers or hoods 
over each hole 19 such as scuppers 20 seen in FIG. 1. Each of the three 
scuppers form an upstanding covering over each of the holes 19 
respectively, but spaced apart therefrom to engage or capture a small 
portion of the external airflow around chamber 10 and scoop such portion 
into the pocket so that it will be directed into the hole 19 covered by 
the pocket. Thus each pocket as suggested by scupper 20 in FIG. 1 has an 
open-end portion 21, a blind closure end portion 22, and side portions 23 
and 24 extending therebetween. These portions comprise surfaces which 
slope from the open-ended air inlet area 21 toward blind terminus 22 from 
which there is no outlet or escape, whereby airflow exerting the inlet 21 
is forced through hole 19 and thence into chamber 10. 
Of particular and critical importance is the angular orientation 27 of the 
open-end portion 21 of the scuppers 20 to the centerline 26 of each lobe 
11. The direction of this angular orientation 27 controls the direction of 
rotation 28 of the decelerator 10. 
Equally important is the angle of offset 29 and protrusion 30 of the 
scupper 20 into the air stream away from the bottom panel 13, shown in 
FIG. 2 and FIG. 3. The angle of offset 29 and protrusion 30 control 
attainable spin rate in the desired direction 28. 
It is thus possible to impart a desired spin rate in the desired direction 
regardless of the conditions at the time the decelerator is released into 
an air stream. 
As an example, for a clockwise angular orientation 27, a certain angular 
offset 29, and protrusion 30, a specific body 15 attached thereto and 
subjected to a 12,000 RPM counter-clockwise spin, upon release into a 
1,000 F/S air stream will de-spin in 3/4 seconds and commence spinning in 
the opposite, clockwise, direction at the desired rate. 
While an illustrative example of the device according to the present 
invention has been described herein, many variations thereof are possible 
within the scope of the teachings of this disclosure. Accordingly, the 
scope of the invention is not to be limited by the herein described 
example.