A YEAR AFTER they were invented, both sides in Ukraine are already fielding thousands of racing drones with improvised warheads. Ukraine’s defence ministry calls them kamikazes, because the warhead destroys the drone itself. They are also known as First Person View (FPV) drones because the operator dons goggles that show a video feed from them as they fly. They can carry out strikes that would be out of reach of other weapons. In one clip that has been posted online FPVs dive into a tunnel to attack a Russian tank. In others they race after and destroy speeding vehicles. Faster, nimbler and cheaper than regular drones, they could transform warfare, claim analysts. How?