A new Ukrainian video shows their latest weapon: an interceptor drone armed with two shotguns. Previous videos had shown such drones blasting Russian Mavic quadcopter bombers out of the sky. Now we see the technical ingenuity behind this scourge of the skies.
Fighting The Kick
As anyone who has ever fired a 12-guage knows, they pack quite a kick. Following Newton’s law of the conservation of momentum, if you throw a lot of lead forward at high speed, the shotgun is pushed backwards proportionately.
This is a challenge for anyone wanting to mount a firearm on a small drone. The recoil is enough to knock a drone off course and may cause the operator to lose sight of the target. Worse, the sudden strain may damage the airframe, and a heavy mount is needed to absorb the forces involved.
Some developers simply accept that recoil is going to be an issue, as seen in a video of a rifle-armed drone tested by the Chinse police. Others have devised complex systems to counter it. The Israeli TIKAD system has the weapon set on six robotic arms which automatically flex to compensate for recoil and keep it pointed towards the target. The Spanish Baduga drone sniper system has gyro-stabilization to counter recoil.
In Ukraine, both sides have attempted to mount firearms on drones with recoil mitigated by an older technology. Small arms historian Matthew Moss carried out an analysis of one Russian project on his site The Amourer’s Bench. This launched a counterweight backward at the same time as the projectile is fired forward, a technique which Moss dates back to the 1910s and the recoilless guns developed by Commander Cleland Davis of the U.S. Navy.
Davis tried experimentally fitting these to early aircraft as anti-Zeppelin and anti-submarine weapons. They countered the recoil of the projectile by firing a mass of buckshot packed in grease backwards. The ’Davis Gun’ was not successful in putting big guns on biplanes. But the design evolved into a series of large caliber U.S. Army anti-tank weapons known as Recoilless Rifles mounted in Jeeps and other light platforms.
The Russian engineering team which used the same principle complained they were having difficulty interesting anyone. They were particularly irked later on to see a similar Ukrainian design in action, shooting down their drones.
A Backwards And Forwards Solution
Several videos have emerged of Ukrainian shotgun drones bringing down Russian Mavics. The grenade-dropping Mavics are said to be as deadly as FPVs in terms of the number of casualties they cause and are difficult to down by conventional means. An interceptor drone to track and destroy them at close range is an efficient solution.
The new video shows the shotgun drone in close-up detail. The operator loads a shotgun cartridge into a short tube and clips it into place. This is standard shotgun ammunition, which one commenter identifies as 12-gauge number 4 buckshot with a load of around 25 pellets of .13″ diameter. Other details are less obvious.
“They’re careful not to show too much, but they do show it’s electrically ignited,” Moss told me. “Looks like they have removed the original primer from the cartridge.”
The shotgun tube is supported by a single clip, and there are four clips in all. A closer look shows two pairs of tubes mounted back-to-back.
“You can see that there’s a charge that fires to the rear,” says Moss.
In theory using two cartridges firing in opposite directions should completely cancel out recoil, if the loads are exactly the same.
“The lack of recoil is likely a combination of the use of another identical cartridge as a counterweight charge and the gun system being mounted on a fairly powerful, sophisticated drone,” says Moss.
A backward-and-forward firing shotgun would be extremely dangerous in other situations. But for a weapon fired from a drone, it provides what Moss calls a “simple and elegant” solution to a challenging problem.
The lack of recoil means that if the operator misses with the first shot, or if the target is only damaged, they can rapidly aim again with the second barrel. And high in the air, random shot fired backwards should not be an issue.
In the video the shotgun drone fires at a paper target from a range of about 15 feet and appears to be accurate with a fairly dense pattern of shot. One pellet should be enough to bring down a drone. There is practically no visible recoil.
Aiming At Other Targets
Shotgun drones might be a useful weapon against the increasing number of Russian fiber drones which are controlled via a fiber-optic cable and are impossible to jam.
In principle they could also be used against ground targets, though the noise of the drone would likely give people on the ground a chance to get away. Also, this is a much bigger, slower target than FPVs and easier to shoot down. It might be very useful for urban combat though: a quadcopter loaded with 12-gauge breaching rounds could go through a building, knocking down doors and checking inside rooms.
Also, a duel between a soldier with an assault rifle and a drone with a shotgun could go either way. And if the drone operator loses, they can always get another drone.
At present, drone armament consists mainly of explosive warheads or bombs, with a few net guns. The many efforts to field rocket launchers or firearms have produced few visible results. But the ”recoilless shotgun“ looks like to be an effective, lightweight solution for reusable interceptor and attack drones. We may see a lot more of these, with shotguns and other weapons, in the coming months.
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