Ukrainian engineers repair a Vampire hexacopter, one of the most commonly used drones for bombing missions. Viacheslav Madiievskyi/Ukrinform/NurPhoto A Ukrainian drone unit said it attacked over 230 pieces of Russian artillery in two days. It used a special munition designed to target the barrels of howitzers and other field guns. Fedorov said it was part of a two-stage operation involving intense flurries of drone strikes. An elite Ukrainian drone unit said on Tuesday that it had used a new a