Designed initially as an interceptor the ME Bf 109 fulfilled a number of roles. The model E 'Emil' saw the most service during the Battle of Britain in the summer of 1940. The E-4 was the standard set up at the beginning of the Battle of Britain with modified 20mm MG-FF/M wing cannon capable of firing a new improved explosive shell. The E-7 was the first variant able to carry a 300 litre fuel drop tank addressing the previous problem of the 109 only being able to spent 15mins over the South Ea