You can with an explosively formed penetrator [0]. In fact, I don't think it would be all that difficult. Take, for example, the BLU-108 submunition [1] [2]. I

You can with an explosively formed penetrator [0]. In fact, I don't think it would be all that difficult. Take, for example, the BLU-108 submunition [1] [2]. It deploys four independent "skeet" submunitions, each of which weighs 3.4 kg. The warheads themselves weigh less than 1kg. The skeets are ejected from the BLU-108 dispenser with a high angular velocity, resulting in precession. They also deploy a retarding parachute. The precession causes them to "look" in a cone-shape of decreasing diameter as they descend (using passive infra-red and active laser sensors), and when they detect a valid target they fire. These are designed to destroy tanks. You couldn't just drop a skeet submunition from a drone -- you would need some way of giving it the required angular velocity. But if you're prepared to sacrifice the drone (which seems reasonable for destroying a tank), you could fix the explosively formed penetrator to the bottom of the drone along with a sensor package. Then you use the drone's own control authority to aim the weapon and detonate it when it's pointed at the target. I'm not sure what the warhead's effective range would be, but probably somewhere between 10m and 100m. The payload for the drone would be around 3kg. It should be noted that explosively formed penetrators don't require much technical sophistication to build and a cheap digital camera could be used for aiming. It may seem seem surprising that such a small weapon can destroy a tank, but tank armour is optimized according to the expected threat environment, so armour is much thinner on the roof. Explosive reactive armour could probably defeat it, though. [0]: https://en.wikipedia.org/wiki/Explosively_formed_penetrator https://en.wikipedia.org/wiki/Explosively_formed_penetrator [1]: https://en.wikipedia.org/wiki/BLU-108 https://en.wikipedia.org/wiki/BLU-108 [2]: https://www.youtube.com/watch?v=myuZUxS3Uww https://www.youtube.com/watch?v=myuZUxS3Uww