During the first half of the Second World War, the Messerschmitt Bf109 E was the main fighter of the German Air force. The E-4 housed a 1,100 hp Daimler Benz DB 601Aa engine and was armed with two 7.9mm machine guns on the nose, as well as 20mm cannon on each wing. For some aircraft, bulletproof glass was used to reinforce the front of the canopy. In addition, a 20mm cannon, which ran through a tube in the propeller was supposed to be installed but was unsuccessful. Displaying superb acceleration and diving ability, the E-type planes overpowered RAFs Hawk Hurricane and equaled the Spitfire fighters in the Battle of Britain. However, with a flight range of only 560km, the E-4 planes were limited to just fifteen minutes of combat over British skies. Thus, the bombers were not given sufficient support and sustained heavy damage. As a result, the Luftwaffes strategy to bomb England into surrender ended in failure. To deal with the drawback, the E-4 planes were equipped with an additional 300L fuel tank. These improved fighters, called E-7, were first deployed at the end of 1940. After the Battle of Britain, the E-4/7 planes were sent to the front lines of Northern Africa. As the Bf109 F-type fighters production advanced, the E-4/7 was retired from the front lines. However, some veteran pilots continued to use the E-4/7 mainly for ground support duty until the summer of 1942.