Device for pneumatic launching of a drone
A device for pneumatic launching of a drone includes a launch tube, a pressurization chamber situated at the rear of the tube and provided with a passage opening leading into the tube, and a device for temporarily closing the passage opening. The temporary closing device is arranged to change from a closed configuration to an open configuration instantaneously under the action of the gas pressure inside said chamber, after the latter has reached a trigger pressure, and the cross section of the passage opening is sufficiently large that, instantaneously with the change to the open configuration, the gas pressure prevailing in the chamber and the space located behind the drone, then in communication with each other, is the desired launching pressure for the drone.
1. A device for pneumatic launching of a drone, the device comprising:
a longitudinal launch tube having a first, rear end, which is closed, and a second, front end, which is open, and an interior of the launch tube defines a launch chamber intended to receive a drone and in which there is a seat against which the drone is positioned before the drone is launched;
a pressurization chamber located at the rear end of the launch tube and capable of being pressurized by a pressure source, the pressurization chamber having a first, front end in which is provided a passage opening leading into the launch chamber and, in use, behind the drone placed against the seat; and
temporary closing means for temporarily closing the passage opening, the temporary closing means being capable of switching instantaneously from a closed configuration, in which the passage opening is closed in a sealed manner, to an open configuration in which the passage opening is fully open; and
the temporary closing means being arranged to switch from the closed configuration to the open configuration instantaneously under action of a gas pressure inside the pressurization chamber, after the pressurization chamber has reached a predetermined pressure, referred to as a trigger pressure, and a cross section of the passage opening being sufficiently large that, instantaneously with a switching of the temporary closing means from the closed configuration to the open configuration, the gas pressure prevailing in the pressurization chamber and a space located behind the drone, then in communication with each other, is a desired launching pressure for the drone; and
wherein the device comprises said pressure source, which is formed by an internal gas source arranged inside the pressurization chamber, said pressure source comprising, placed in the pressurization chamber, a diffuser and a second reactant, the diffuser delimiting a reservoir including a first reactant, the first and second reactants, when brought into contact with each other, reacting to generate a gas for pressurizing the pressurization chamber, a solenoid valve being arranged so as to allow selectively a fluid communication between the reservoir and the pressurization chamber.
2. The device according to claim 1 , wherein the cross section of the passage opening is between 30% and 50% of a cross section of the launch chamber.
3. The device according to claim 1 , wherein the temporary closing means are arranged to switch from the closed configuration to the open configuration automatically upon the gas pressure inside the pressurization chamber reaching the trigger pressure.
4. The device according to claim 3 , wherein the temporary closing means comprises a rupture disc assembly that is disposed at the passage opening and comprises a calibrated diaphragm extending across the passage opening so as to close the passage opening, the calibrated diaphragm being dimensioned to break at the trigger pressure.
5. The device according to claim 4 , wherein the rupture disc assembly is removably fixed to the pressurization chamber.
6. The device according to claim 5 , wherein the rupture disc assembly comprises a support ring and a fixing ring of same dimensions and fixed to each other by fixing members passing through holes provided for this purpose in the support ring and the fixing ring, with a periphery of the calibrated diaphragm sandwiched between the support ring and the fixing ring, the rupture disc assembly being removably fixed to the front end of the pressurization chamber also by said fixing members.
7. The device according to claim 1 , wherein the rear end of the launch tube is formed by a base removably fixed to an inner shoulder of the launch tube, from which base a tubular part extends, a longitudinal axis of the tubular part being coaxial with a longitudinal axis of the launch tube and the tubular part defining, together with the base, the pressurization chamber, a gasket being interposed between the tubular part and an inner annular edge of the inner shoulder.
8. The device according to claim 1 , wherein the first reactant is hydrogen peroxide (H 2 O 2 ) under pressure and the second reactant is a potassium permanganate (KMnO 4 )-based solid catalyst.
9. The device according to claim 1 , wherein the device further comprises a launch sabot capable of being received in the launch chamber and brought into contact against the seat, the launch sabot being configured to contain and surround the drone before launch and during the movement of the drone along the launch tube during ejection.
10. The device according to claim 9 , wherein the launch sabot is formed of several separable segments.