How Can Ukrainian Drones Keep Dropping Grenades Into Open Tank Hatches?
Small drones carry small warheads, so unless they can hit a tank in exactly the right spot they may barely scratch the armored exterior. But often there is an easy way. In a video from Ukraine’s Shadow Division posted on May 8th, a drone hovers above an abandoned Russian T-90M tank and, with exquisite care, drops an American M67 hand grenade through an open hatch.
A light puff of smoke is followed by thicker smoke. The fire takes hold and soon the tank is ablaze, with a series of explosions as the stowed ammunition and smoke grenades cook off in the heat. Before long, Russia’s most advanced tank, valued at over $4m is a burning wreck, thanks to a $50 grenade from a $2,000 drone. The M67 is a fragmentation weapon, useless against the outside of a tank, but from the inside its six ounces of explosive is enough to destroy one.
The next day Shadow Division posted another such wrecking job on another T-90M on May 9th . Many, many such videos showing Russian tanks destroyed by grenade drops through open hatches. Which leads to the question: “Why don’t Russian tank crews simply close the hatches when they leave?”
Russian Tanks’ Deadly Design Feature
The simple answer is that leaving hatches open is standard practice. The hatches are extremely heavy. They need to be protected to the same degree as the rest of the tank roof, which means at least two inches of armor plating weighing a hundred pounds or more. Some tank hatches are sprung to make opening easier, and the IDF Merkava even has power-assisted hatches, but Russia uses simpler technology. So closing a tank hatch takes time and effort. And anyone baling out of a Russian tank is likely to be in a hurry.
Russian tanks have a design trade-off which has the ammunition carousel for the automatic loader sharing space with the crew. This means that the crew is three rather than the four needed in most Western tanks, but it also means that any penetrating hit is likely to set off the stored ammunition, usually a with huge explosion and ‘turret toss,’ flinging the turret high into the air, killing the occupants instantly.
If the tank strikes a mine, or is hit by a missile or FPV drone, and is immobilized, the commander will order the crew to abandon it. A few seconds mean the difference between getting away to a safe distance when the tank explodes, or being at ground zero for a massive fireball. Crews understandably get out and away as fast as they can, leaving hatches open behind them.
An added issue is the presence of multiple FPV drones which often hunt down surviving crew members. As the old joke goes, when a bear is chasing your party, you do not need to be faster than the bear, just faster than the slowest member of the party.
Mosquito Screens For Drones
Leaving hatches open is costing the Russians a fortune in destroyed equipment. So what would happen if crews were compelled to shut tank hatches on pain of serious penalty?
Even if some tankers managed to remember the order in the heat of battle, and decided to risk their lives carrying it out, each tank had three crewmembers, each escaping through their own hatch. If compliance with the order was 50%, then the chance of all three hatches being shut would be 50% x 50% x 50% or 12.5% , which is just one in eight. Even if compliance was 80%, around half the abandoned tanks would have one or more hatches left open.
In the case of the T-90M, it looks like two of the three hatches were closed. But the commander’s hatch was not. It only takes one open hatch to drop a grenade through.
A simple solution is a lightweight wire mesh screen above the hatch, something like a screen door for keeping out insects and with the same function of allowing fresh air in while keeping nuisances out and easy to open and close. This approach is shown in another Shadow Unit T-90M demolition video, this one from May 6th. Two hinged screens, seemingly made from sections from chain link fence, protect the gunner’s and commander’s hatches. However, as well as leaving the hatch open, the commander also left his hatch cover open, and again a single M67 grenade sends $4m of Russian hardware to a fiery end.
In yet another example seen on May 9th both top hatches and their mesh screens were left open in an abandoned T-90M. The result is inevitable.
Persistence Always Pays Off
The screen door approach does not give complete protection, just temporary respite. Another video, this one from April 10th, shows a Russian tank with a wire mesh over the commander’s hatch. On closer inspection the mesh has a large circular hole blown in it, likely from a previous grenade. This allows a Shadow unit drone to drop the usual M67 through the opening and finish another Russian tank.
The popular roof screens over Russian tanks should also stop any grenades dropped from above, but they can only survive a few hits. When there is no jamming or defensive fire, drone operators can keep coming back and dropping as many bombs as needed to finish the job.
For example a video from February shows a Russian tank protected by a roof screen made of explosive reactive armor (ERA) blocks, a design now installed at the factory for new Russian tanks. A very persistent drone operator keeps returning to the attack, dropping a variety of different munitions, blasting away the roof screen one piece at a time. After eight attempts the way to the hatch is clear, and, just as it is getting dark, two more drops through the open hatch with what look like RGT 27S2 thermobaric grenades finally ignite and destroy the tank.
There is a similar example from May 10th, a video in which we only see the final act but the roof screen above the commander’s hatch has been systematically destroyed and a small Ukrainian-made drone bomb produces a spectacular fireball.
Just as bank robbers can drill their way into any vault given sufficient time undisturbed, no add-on roof protection will work against precise, repeated bombing.
Russian tank crews may also feel that shutting the hatches will not help their vehicles survive for long. After nightfall. Because that is when Ukraine’s heavy Baba Yaga drones comes out. These are far larger than the quadcopters that fly by day, and can drop mortar bombs, RPG warheads and even anti-tank mines, destroying tanks whether their hatches are left open or closed.
Meanwhile, the Shadow Division, and many others like it, continue to destroy high-end Russian armor on a daily basis.
