Why are these things as effective as they are in the ukrain-russian war? Don't these things show up on radar and therefor vulnerable to conventional anti air defence. Before the start of the war experts where warning that russia could lock down the air space of the whole of europe. These single propeller planes can not be as fast as jet engines and need to be almost on top of their target to drop bombs on them? What is preventing Russia from building these things in the thousands and I don't know patrol the skies of eastern ukrain with it?