Dual-tandem unmanned air vehicle system

An unmanned air vehicle system which is intended for launch from a platform such as an aircraft or a ship and to follow other than a ballistic trajectory includes a pair of substantially similar air vehicles in a tandem relationship. A unitary tubular airframe is provided coextensive with both air vehicles. The nose of a second air vehicle is nested in the tail member of a first air vehicle. A rocket booster is mounted in the tail of the second air vehicle and ignited for launch of both air vehicles as a unit. Thereafter, a pyrotechnic separating mechanism is actuated for bisecting the tubular airframe intermediate the tail member of the first air vehicle and the nose of the second air vehicle. Following separation, each air vehicle has a gas turbine engine which is ignited for powering its associated air vehicle to its destination. Electrical connections from the launch platform to the vehicle system are made to the first air vehicle and the second air vehicle is, in turn, electrically connected to the first.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates generally to an unmanned air vehicle system 
intended to follow other than a ballistic trajectory and, particularly, to 
such a system which utilizes substantially similar forward and aft air 
vehicles in a tandem relationship. 
2. Description of the Prior Art 
It has long been known to construct multi-stage ballistic missiles powered 
by either solid fuel or liquid fuel rocket engines with two or more stages 
connected in tandem. Usually, the engines for the different stages are 
operational in succession, that is, when the fuel of one stage is spent, 
that stage drops off and a successor unit is ignited. Typical of such 
constructions are U.S. Patents to Howison U.S. Pat. No. 3,262,266, to 
Crossett U.S. Pat. No. 3,245,351, to Shryock U.S. Pat. No. 3,310,947, and 
to Blankenagel U.S. Pat. No. 3,491.692. 
In a number of instances, there is provision on a forward vehicle of such a 
tandem vehicle arrangement for guiding or deflecting exhaust gases 
laterally to avoid harm to an aft vehicle. The patents to Howison and 
Crossett, noted above, as well as to Chilosky U.S. Pat. No. 3,233,548, to 
Osborne et al. U.S. Pat. No. 3,760,730, and to Hickman U.S. Pat. No. 
2,503,271 disclose various arrangements for achieving this goal. 
It is also known to mount plural rockets in an elongated launch tube with 
associated guide and launch equipment for each rocket and to mount the 
launch tube, for example, beneath the wing of an attack aircraft or 
onboard a ship. Typical instances of tandem rocket launchers are found in 
U.S. Patents to Hagelberg et al. U.S. Pat. Nos. 4,342,252 and 4,433,606, 
and to Gould U.S. Pat. No. 3,199,406. Unfortunately, launch tubes add 
significantly to the weight and drag of the attack aircraft and, 
therefore, significantly reduce its performance. Nonetheless, it would not 
be desirable to discard the launch tubes following launch of their 
associated rockets because of their substantial replacement cost. 
It has also been known to provide a multiple-unit projectile whose 
component units separate all the projectiles in flight, the following unit 
striking a target at a time delay interval after the leading unit strikes, 
whereby the maximum penetration and destructive effect of the successive 
impacts of the projectiles on the same spot or area of the target may be 
attained. The U.S. Pat. No. 2,804,823 to Jablansky is typical of such a 
known construction. 
It was with knowledge of the prior art as just described that the present 
invention has been conceived and is now reduced to practice. 
SUMMARY OF THE INVENTION 
The present invention comprises an unmanned air vehicle system which is 
intended for launch from a platform such as an aircraft or a ship and to 
follow other than a ballistic trajectory. It includes a pair of 
substantially similar air vehicles in a tandem relationship. A unitary 
tubular airframe is provided coextensive with both air vehicles. The nose 
of a second air vehicle is nested in the tail member of a first air 
vehicle. A rocket booster is mounted in the tail of the second air vehicle 
and ignited for launch of both air vehicles as a unit. Thereafter, a 
pyrotechnic separating mechanism is actuated for bisecting the tubular 
airframe intermediate the tail member of the first air vehicle and the 
nose of the second air vehicle. Following separation, each air vehicle has 
a gas turbine engine which is ignited for powering its associated air 
vehicle to its destination. Electrical connections from the launch 
platform to the vehicle system are made to the first air vehicle and the 
second air vehicle is, in turn, electrically connected to the first. 
The combined launch airframe can be configured for dimensional 
compatibility with common missiles such as the AIM-9 Sidewinder or the 
AIM-120 AMRAAM for the purpose of utilizing existing standard launch 
rails. 
Furthermore, by combining two unmanned air vehicles in tandem, their 
aerodynamic drag contribution during external carriage on a manned 
aircraft is minimized. 
Additionally, by combining two unmanned air vehicles into a single 
airframe, cost savings can be realized at the time of original manufacture 
and operations and support savings can also be achieved. 
Other and further features, advantages, and benefits of the invention will 
become apparent in the following description taken in conjunction with the 
following drawings. It is to be understood that the foregoing general 
description and the following detailed description are exemplary and 
explanatory but are not to be restrictive of the invention. The 
accompanying drawings which are incorporated in and constitute a part of 
this invention, illustrate one of the embodiments of the invention, and, 
together with the description, serve to explain the principles of the 
invention in general terms. Like numerals refer to like parts throughout 
the disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Turn now to the drawings and, initially, to FIG. 1 which illustrates an 
unmanned air vehicle system 20 generally embodying the present invention. 
A primary purpose of the invention is to package a pair of unmanned air 
vehicles together to improve the prelaunch and launch geometry of the 
system. Thus, the system 20 includes a forward air vehicle 22 and an aft 
air vehicle 24 which mutually assume a tandem relationship having a common 
longitudinal axis. Consistent with this concept, in a preferred 
construction, the system 20 includes a unitary tubular air frame 26 which 
is coextensive with the forward and aft air vehicles 22, 24. The airframe 
26 is preferably of circular and substantially constant cross section, but 
may be of a variety of other shapes without effectively altering the 
invention. In any event, the airframe 26 extends without interruption 
between a forward end of the system 20 (at the left, viewing FIG. 1) and 
an aft end of the system (at the right, viewing FIG. 1). 
The forward and aft air vehicles 22, 24, respectively, are substantially 
identical. Therefore, a description of the forward air vehicle 22 which 
will now be presented can also be taken as a description of the aft air 
vehicle 24. In those instances in which differences do exist, they will be 
explained. 
The forward air vehicle 22 includes a nose member 28 which is suitably 
mounted to the tubular air frame 26 as by welding, bonding, or by use of 
mechanical fasteners. In a typical arrangement, the nose member 28 carries 
the payload, whether that be instrumentation, ordinance, or other cargo, 
as desired. Immediately to the right of the nose member 28, viewing FIG. 
1, in typical fashion, is a guidance and control section 30 which might 
include a suitable connector 32 for connecting the airborne 
instrumentation in the air vehicle 22 to that in the launch platform (not 
shown) which may be, for example, an aircraft or a ship. 
To the right of the guidance and control section 30, as seen in FIG. 1, is 
a tail member 34 which contains a main propulsion system 36 of the air 
breathing variety, typically a gas turbine engine. An intake air duct 38 
draws air to the propulsion system 36 from an inlet 40 which is flush with 
the outer peripheral surface of the air frame 26. In a similar manner, 
outlet air ducts 42 extend to outlets 44 which are similarly flush with 
the peripheral surface of the tubular air frame 26. The tail member 34 
defines a rearward facing cavity 46 which is suitably shaped to receive, 
in a nesting relationship, the nose member of the aft air vehicle 24. It 
will be appreciated that the relationship between the nose member of the 
aft air vehicle 24 and that of the outlets 44 through which exhaust gases 
from the propulsion system 36 are directed is such as to assure that no 
damage occurs to the aft air vehicle 24 during operation of the propulsion 
system. 
The forward air vehicle 22 is also provided with a set of suitable air 
foils 48, 50 which are operable in a known manner to provide both lift and 
control for the air vehicle. 
The interface between the forward air vehicle 22 and the aft air vehicle 24 
will now be described with particular attention to FIGS. 2 and 3. A 
T-shaped frame member 52 includes a forward extending (to the left in FIG. 
1) flange 54 and an aft extending (to the right in FIG. 1) flange 56. The 
nose member 28 of the aft air vehicle 24 is suitably attached, as by 
welding, bonding, or by use of mechanical fasteners, to the forward flange 
54 and the tubular air frame 26 is similarly attached to the aft flange 
56. A pair of mating electrical connectors 58 (FIG. 2) on the forward air 
vehicle 22 and on the aft air vehicle 24 enable the interconnection of the 
airborne electrical system for the latter to be connected to that of the 
former. It was earlier explained that the forward air vehicle 22 has a 
connector 32 for electrical connection to the launch platform. In this 
manner, the system 20 is compatible with an existing launch platform 
without requiring any change to its electrical system or to its associated 
electrical connectors. 
The frame member 52 is also provided with an annular channel member 60 for 
reception therein of a linear shaped charge 62. At an appropriate time, 
the shaped charge 62 is ignited to sever the tubular air frame 26 in the 
region of the rib member 52 such that, as seen in FIG. 3, the air vehicles 
22, 24 are independent of each other and can proceed in separate 
trajectories. 
The aft air vehicle 24, in contrast to the forward air vehicle 22, is 
provided with a booster propulsion unit 64 suitably mounted within its aft 
cavity 46. The booster propulsion unit 64 is typically a rocket motor. 
The operation of the unmanned air vehicle system 20 will now be described. 
As the system 20 awaits launch on its platform, the airborne electrical 
system for the forward air vehicle 22 is connected, via connector 32, to 
that of the launching platform. In turn, by reason of the electrical 
connector 58 which has continuity with that of the connector 32, the 
airborne electrical system for the aft air vehicle 24 is likewise in 
communication with that of the launching platform. In a typical sequence 
of events, the booster propulsion unit 64 is ignited and the entire system 
20 is released from the launching platform. The system 20 proceeds under 
the power of the booster propulsion unit 64 for a predetermined period of 
time at which point operation of the main propulsion systems 36 for each 
of the air vehicles 22, 24 is initiated. Again, after a predetermined 
period of time, the shaped charge 62 is ignited thereby separating the air 
vehicles 22, 24, each proceeding to its own destination. The booster 
propulsion unit 64 may remain with the aft air vehicle 24 for its entire 
mission. In the alternative, a suitable shaped charge, similar to the 
shaped charge 62, may be provided to separate the booster propulsion unit 
from the aft air vehicle. 
While preferred embodiments of the invention have been disclosed in detail, 
it should be understood by those skilled in the art that various other 
modifications may be made to the illustrated embodiments without departing 
from the scope of the invention as described in the specification and 
defined in the appended claims.