Battle of The Beams - Night Bombing

Night Bombing

During the early 1930s, the concept of a night bombing strategic campaign began to become paramount in military aviation circles. This was due to the ever-increasing performance of bombers, which were beginning to have the capability to strike across Europe with useful bomb loads. These aircraft were slow and lumbering, easy prey for interceptors, but this threat could be essentially eliminated by flying at night. A bomber, painted black, could be spotted only at very short ranges. And as the bomber's altitude and speed increased, the threat from ground based defences was greatly reduced. Simply put, planners believed that "the bomber will always get through".

The problem with night bombing is that the same limitations in visibility meant the bomb aimers would have a difficult time finding their targets, especially a blacked-out target at night. Only the largest targets, cities, could be attacked with any probability of success. The concept of huge fleets of bombers flying unhindered over their enemy was so reprehensible that the Royal Air Force (RAF) built up its night bomber force largely as a deterrent. It was hoped that the fear of unrestrained attack against German cities would prevent the Luftwaffe from considering attacks against England.

To support this mission, the RAF invested very heavily in navigation training, equipping their aircraft with various equipment, including an astrodome for taking a star fix and giving the navigator room to do calculations in a lit workspace. They put this system into use as soon as the war began and were initially happy with its success. In reality, the early bombing effort was a complete failure, with the majority of bombs landing miles away from their intended targets.

The Luftwaffe did not take such a fatalistic view of air warfare, and continued to research accurate night bombing against smaller targets. Neglecting any training in celestial navigation, they invested their efforts in radio navigation systems to solve the same problem. The Luftwaffe concentrated on developing a bombing direction system based on the Lorenz concept through the 1930s, as it made night navigation relatively easy by simply listening for signals on a radio set, and the necessary radios were already being installed on many aircraft.

Lorenz had a range of about 30 miles (48 km), enough for blind-landing but not good enough for bombing raids over the UK. This could be addressed by using more powerful transmitters and highly-sensitive receivers. In addition the beams of Lorenz were deliberately set wide enough that they could be easily picked up at some distance from the runway centreline, but this meant their accuracy at long ranges was fairly limited. This was not a problem for blind landing, where the distance covered by the fan-shaped beams decreased as the airplane approached the transmitters, but for use in the bombing role this would be reversed, and the system would have maximum inaccuracy over the target.