The Dornier 17 was originally designed as a mail carrier with room for 6 passengers but proved unsuitable for that role but it was suggested it could be a fast bomber. The earlier variants had a relatively small cockpit and bomb aimer's position and a slim fuselage and quickly gained the nickname of 'flying pencil'. Early models included the BMW powered E and F, bomber and reconnaisance versions and the DB600 powered L and M. A shortage of DB600's meant the M switched to a Bramo radial engine and the corresponding Bramo powered recce version was the P. The next production models were the Z series. These had the Bramo engines with an all new enlarged cockpit, with more defensive guns and a greater bomb load. It proved to be underpowered so the bombload had to be reduced. Despite this the Z-1 and Z-2 were one of the Luftwaffe's main bombers in the early part of the war and took part in large numbers in the Battle of Britain. They took heavy losses over Britain but survivors carried on being used in the Mediterranean and Eastern fronts until eventually being replaced by the superior Ju88.