The Fieseler Fi103 V1 and the Republic/Ford JB2 Loon. The V1 earned a fearsome reputation when more than 10,000 of them were fired at Britain with devastating effect. They may have been crude, but by and large they worked! They were known to the Brits either Buzz-Bombs or Doodlebugs. They had a peculiar rasping engine noise and Londoners soon worked out that if one was overhead and that noise stopped, you RAN because it was on it's way down! The RAF managed to shoot down large numbers of them, but later evolved a method of tipping their gyros by getting a wingtip of the fighter under the wing