No. 1321 Bomber (Defence) Training Flight RAF was first formed at RAF Bottesford on 1 September 1944 as a fighter affiliation unit to train bomber crews from No. 5 Group Bomber Command how to defend their aircraft. The Flight was disbanded two months later on 1 November 1944 and absorbed by the units they trained before, 1668 Heavy Conversion Unit and 1669 Heavy Conversion Unit. 1. * Ballistic performance of the bomb casing at various altitudes and speeds 2. * Testing of the equipment from the Atomic Weapons Research Establishment under operational conditions