The present invention relates to a launch system for air vehicles. More specifically, the present invention relates to launching unmanned air vehicles (UAVs) that are unable to be launched by hand or UAVs that either lack undercarriage or are unable to use undercarriage to take-off.
At present, there exist lightweight UAVs that weigh around 10 kg and which can be hand-launched by simply picking them up and throwing them. Realistically, it is only possible for vehicles significantly lighter than 10 kg to be hand-launched. If, however, the UAV is heavier than 10 kg, it becomes much more difficult to launch the vehicle. These vehicles can be powered by a range of propulsion means, such as a rear mounted propeller driven by a petrol, electric or diesel engine, or a jet engine or similar thrust-generating propulsion mechanism.
Currently, heavier UAVs are launched using a catapult device, but these catapults are cumbersome and generally unsuitable for use in fast moving situations: the catapult may need to be carried by a single person, as they are about 20 ft long, thus will be cumbersome to carry around due to their weight and dimensions being at the upper threshold of the capabilities of a single person; and the catapults are slow to set up due to their size, dimensions and weight.
Heavy and large UAVs are preferably provided with undercarriage to enable them to take-off and land on runways or landing strips, but this solution is generally reserved for more capable vehicles. Lower cost vehicles, less capable vehicles and smaller vehicles usually have to do without undercarriage and so an alternative launch means is required.
Accordingly, the present invention provides a mating component for engaging with a projectile wherein said mating component is configured to harness said projectile when said projectile is launched.
An advantage of using a mating component, for example the cap 90 described below, with a projectile launcher, for example a mortar launcher, to harness the energy of the projectile, for example a fin-stabilised mortar, is that the energy can be converted into acceleration for a vehicle such as a UAV as will be described below.
Specific embodiments of the invention will now be described, by way of example only and with reference to the accompanying drawings that have like reference numerals, wherein:—
a, 34b, 34c and 34d show an embodiment featuring a re-usable cap;
a, 35b and 35c show an alternative embodiment featuring a re-usable cap;
The general principles of the invention will now be described with reference to
Referring first to
The base 10 of the mortar launcher, to which one end, the fixed end, of the mortar launcher tube 50 is hingedly fixed, is put in position on the ground at the desired launch site. The fixed end is a closed end of the mortar launcher tube 50. The other end of the mortar launcher tube, the free end, is supported by a stand 60 that rests on the ground and thus supports the end of the tube 50. The free end of the mortar tube 50 is open, allowing an inert fin-stabilised mortar round 80 to be inserted into the tube 50 and to exit the tube 50 when launched.
In this embodiment the UAV 20 is mounted on takeoff runners 30 that are formed on top of the mortar launcher tube 50, mounted using a latch 100 that will only release the UAV 20 when it is moving in the correct direction, i.e. the direction of the mortar round 80 as it leaves the mortar tube 50, above a certain threshold of force. The latch 100 thus prevents the UAV 20 from sliding towards the ground or moving from position once it has been mounted on top of the mortar launcher tube 50 in readiness for launch. The latch 100 also prevents the UAV 20 sliding off the mortar launcher tube 50 too early when there isn't enough force from the shock cord to pull the UAV 20 clear of the mortar launcher tube 50.
It should be noted that alternative arrangements are possible for how the UAV 20 is mounted and secured on the mortar launcher tube 50 and these will be discussed below.
The engine of the UAV 20 is started before the mortar 80 is launched and once the UAV 20 is mounted and secured atop the mortar launcher 50, so that when the launch of the mortar round 80 is complete the UAV 20 can continue flying under its own propulsion, while the mortar round 80 will drop to the ground. In this embodiment, the UAV 20 has a rear-mounted propeller driven by a small petrol engine, though other types of UAV 20, having different means of propulsion, can be launched instead.
A mortar round 80 is placed into, but near the top of, the free end of the mortar launcher tube 50 by the operator and is fixed in place by the operator sliding a standard-issue slipper plate 110 on to the mortar round 80. The slipper plate 110 is a thin, flat metal plate with a portion cut away that allows it to fit around the mortar round 80 and into two grooves 130 on the sides of the mortar round 80. These grooves 130 can be seen in more detail in
The slipper plate 110 is designed to be connected to a pull cord 70 with a pin so that an operator can pull the cord 70 such that the plate 110 slides out of the grooves in the mortar round 80, releasing the mortar round as discussed below in more detail. To this end, the slipper plate 110 is provided with a hole 111 to accept a pull cord 70, using a pin (not shown) to secure the pull cord 70.
The slipper plate 110 is shown in more detail in
A cap 90 is placed over the free end, or muzzle, of the mortar launcher tube 50 and the slipper plate 110. One end of a shock cord 40 is attached to the cap 90. The other end of the shock cord 40 is attached to a hook 120 underneath the nose of the UAV 20.
In one embodiment of the invention, the slipper plate 110 fits on top of the cap, rather than on between the cap 90 and the muzzle of the mortar launch tube 50. The cap 90 is fitted onto the free end of the mortar launch tube and is formed (as shown in
To allow the slipper plate 110 to easily and quickly fit on top of the cap 90 in operation, the mortar round 80 can be fitted loosely into the cap 90 before insertion into the top of the mortar launch tube 50. The slipper plate 110 is then secured in place so that the tip of the mortar round 80 extends out of the top of the cap 90 to allow the slipper plate 110 to fit into the grooves 130 in the mortar round 80. This allows the mortar 80 to fall to the bottom of the mortar launch tube 50 when the slipper plate 130 is removed, as the mortar round 80 does not form a secure interference fit with the cap 90 when only inserted far enough to allow the slipper plate 110 to fit into the grooves 130 in the mortar round 80. This configuration enables the operator to place the pre-prepared combination of mortar shell 80, slipper plate 110 and cap 90 on to the mortar launch tube in one operation.
Referring now to
Referring now to
Referring now to
Referring now to
Referring now to
It should be noted that no latch 100 is needed, but some mechanism is needed to hold the UAV 20 in place when it is mounted over the mortar launcher tube 50 whilst allowing it to accelerate in the direction of the mortar shell 80 when the mortar shell 80 is launched.
Referring now to
In
The inside, contacting, face 140 of the cap 90 decreases in diameter from one open end 170 to the other open end 160, from bottom end to top end, so that the mortar round 80 mates with the cap 90 when it is launched as it becomes lodged in the cap 90 when the diameter of the cap 90 decreases to the substantially the diameter of the widest diameter of the mortar shell 80, i.e. using an interference fit.
The cap 90 with the 81 mm mortar shell 80 in a preferred embodiment is designed to from a 1 in 48 taper interference fit. It is possible to use other tapers but it should be noted that the cap 90 must have to have a sufficient taper to capture the mortar shell 80.
It is possible to choose a taper that allows the head of the mortar shell 80 to pass through the cap 90 and for the mortar fins to be captured in the cap 90, and this effect is known as “fin grab”. It is noted that in some instances fin grab might be preferable as gives a smoother flight but also opens up the possibility of the cap 90 not capturing the mortar round 80.
In this embodiment, aircraft grade L168 aluminium alloy is preferably used to manufacture the cap 90 but it is conceivable that other alloys could be used instead.
The shock cord used has a 7.5 m length and has an 11 mm diameter, once the shock cord is doubled up to enable the ends to form loops. A single 15 m length shock cord 40 is used with the doubled-up end formed into a loop and connected to the UAV 20 using a metal ring and the two loose ends formed into loops and connected to the cap 90. The doubled up shock cord 40 is taped at regular intervals along its 7.5 m length using a thread based tape to prevent the shock cord configuration from becoming distorted. Alternatively, a shrink wrap could be used at regular intervals to hold the shock cord in the doubled up configuration. This specification and configuration for the shock cord enables it to be used at a suitable range of weights of UAV 20. The ends of the shock cord and the doubled up middle portion of the shock cord utilise a well known twine wrap method, wherein twine is wrapped around the two cords to secure them together to form loops to enable connection to the cap 90 or to the metal rods or wire 190.
In a preferred embodiment, as shown in
A pin with a lock ring is used to connect the looped shock cord ends 40 to the metal rods or wire 190. Alternatively, a bolt and washer can be used to connect the looped shock cord ends 40 to the metal rods or wire 190.
In another embodiment, two shock cords 40 can be used. In a preferred embodiment, two looped shock cords ends are used to connect to opposite sides of the cap 90, preferably connecting the shock cord ends 40 to the metal rods or wire 190 which are in turn connected to the cap 90, to stabilise the trajectory of the mortar once it mates with the cap 90, and this also substantially prevents the cap 90 rotating in flight.
It should be noted that it is preferable to secure the frame to the mortar barrel and that this can be done by using two of the blocks 240 shown in FIG. 24 fastened together clamping the barrel between them and this is shown in
Finally, alternative embodiments of the invention will be described:
It should be noted that the invention could be used to launch both air, underwater and sea vehicles from ships as well as launching a UAV 20 from a ground position.
Other forms of cap 90 are conceivable, the important features being a mating surface or some mechanism for mating with, engaging or capturing the momentum of the mortar shell 80 when it is launched and some means by which to connect the shock cord 40 to this cap 90. Another example would be, instead of a cap, a net made of, for example, reinforced Kevlar strands which covers the muzzle of the mortar launcher and which is provided with some means of connection to the shock cords. As such a more generic term for the cap 90 would be a mating component as this can then cover such a net, as well as different designs of cap. An important factor in alternative designs of cap 90 is that it is preferable to provide for the air inside the mortar tube 50 to escape when the mortar shell 80 is launched from the mortar tube 50 as while designs will work if enough air can escape, the design will be more optimal if there is little resistance to the air escaping as per the preferred cap 90 design described above.
An alternative and preferred embodiment of frame is shown in
The stand can be made from wood or metal and/or commercially available pipes or a combination of wood and metal and/or commercially available pipes to reduce the cost of the stand.
It should also be noted that starting the propulsion means of the UAV 20 before launching it using the method of the invention reduces the force needed to launch the UAV 20, and thus also increases the weight of UAV 20 that it is possible to launch using this method. It is also possible, however, to use this method to launch a UAV 20 without having the propulsion means on until the UAV 20 is in the air.
In an alternative embodiment, there is provided two different re-usable caps:
The first reusable cap is shown in
The second reusable cap is shown in
Both of the re-usable caps have interchangeable components, so a hollow cork cylinder 402 could be used with a hinged metal sleeve 504 with minor modification, e.g. inclusion of a lip 410 on the metal sleeve 504; and the rubber sleeve 502 (with or without slit 506) could be used with the two semi-cylindrical half rings 404 with minor modifications, e.g. to remove the lips 410. Both of the re-usable caps are broadly similar to the normal single-use cap 90, in that they cause an interference fit with a mortar shell 80 by having a tapered inner diameter either by a simple step decrease in diameter or by having a gradient decrease in diameter.
In
Another means for connecting the shock cord 40 to the UAV 20 is by use of a glider release latch instead of a hook. Other means are envisaged, including an electronic release mechanism triggered by either a time or by force measurements, but the important feature is that the release occurs before or at the point when the mortar ceases to pull the UAV 20 forwards and instead acts as drag.
In
It should be noted that instead of using a latch 100, one can angle the stand on which the UAV 20 sits to be at suitable angle to achieve effect of latch 100 as the force pulling the UAV 20 needs to overcome the component of gravity acting on the UAV 20 at rest, thus providing the same effect as latch 100.
It should also be noted that the stands disclosed above that can be moved can be mounted at a position slightly behind the mortar tube 50, thus not clamped to the mortar tube 50, to enable the UAV 20 to experience a better angle of attack when being launched.
The shock cord 40 could be replaced with other means, such as a spring. It should be noted that a shock cord 40 is a form of biased resilient means and a common example of a shock cord 40 is a bungee rope.
It is also noted that the UK armed forces use an 81 mm mortar while the US armed forces use an 82 mm mortar and that the cap 90 should be easily modified to work with either type of mortar. It is also conceivable to use any of the following methods instead of a mortar launcher to provide the force to accelerate a UAV using the shock cord and cap system described above with some modification: a flare gun, a harpoon, a rocket launcher, a rifle or a machine gun with flywheel/bearing to remove rotational movement and maintain thrust in direction of fire.
It is to be understood that any feature described in relation to any one embodiment may be used alone, or in combination with other features described, and may also be used in combination with one or more features of any other of the embodiments, or any combination of any other of the embodiments. Furthermore, equivalents and modifications not described above may also be employed without departing from the scope of the invention, which is defined in the accompanying claims.
Number | Date | Country | Kind |
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08275016 | May 2008 | EP | regional |
0808641.5 | May 2008 | GB | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/GB2009/050507 | 5/13/2009 | WO | 00 | 11/12/2010 |
Publishing Document | Publishing Date | Country | Kind |
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WO2009/138787 | 11/19/2009 | WO | A |
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Entry |
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Notification Concerning Transmittal of International Preliminary Report on Patentability (Forms PCT/IB/326 and PCT/IB/373) and the Written Opinion of the Searching Authority ( Form PCT/ISA/237) issued in the corresponding International Application No. PCT/GB2009/050507 dated Nov. 25, 2010. |
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Number | Date | Country | |
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20110062281 A1 | Mar 2011 | US |