For the first half of the war the RAF struggled with the accuracy of its bombing and target marking. Surveys suggested that a large proportion of bombs were not coming within miles of the target.
Late in 1942 RAF Bomber Command established the ‘Path Finder’ Force led by D.C.T. Bennett. It was a controversial move, resisted by some who felt that there was no need for an elite group of navigators who would mark the target for the main force of heavy bombers. Their early operations did not suggest that such specialisation would make a great deal of difference.
Then technology intervened. The OBOE navigation aid was to produce incredibly accurate target position information. The aircraft flew along a radius guided by a signal transmitted by one of the two participating ground stations – the tone changed if they flew too far inside the circle or too far outside it. Then as they flew over the target a second signal, from the other ground station, indicated the intersection with the radius that marked the target. It was a system that was not only very accurate but also very hard to jam.
In the early trials of OBOE the Belgium resistance was recruited to monitor the accuracy of the bombing of a trial target which, exceptionally, they had been told about in advance. They not only watched the bombing but paced out the distance between the bomb craters for their report.
This was a system that could only be operated by a few aircraft out of the whole bomber force. The Path Finder Force suddenly came into its own:
The losses on heavies in the early days of the Path Finder Force started off rather badly. ln our first month, August, 1942, we averaged 9.1 per cent lost. This was a rate which we obviously could not maintain if we had any hope of retaining sufficient experienced crews to do the job properly. Fortunately, this unhappy state of affairs did not continue after we began to settle down and become effective in our tactics and our planning.
Thus in September the rate dropped to 3.1 per cent for the heavies, and in October 2.6 per cent. It fluctuated thereafter between 1.5 and 4.5 per cent, and this was a rate which we could stand without catastrophic results.
Reverting to Oboe, a very historic occasion was a particular sky-marking raid on Essen. This took place on 9th January 1943. The C.-in-C. detailed a moderate little force of Lancasters to bomb on sky-markers, and all went well. There was complete solid cloud cover below, unlike the better conditions which had prevailed on the other sky-marking raids already carried out.
Thus it was quite clear to those on the ground that the most valuable target in Germany, Krupps works at Essen, was being hit by a blind bombing method.
Hitler immediately called a meeting, at which he himself personally took part, and apparently he was most violent in his denial that such a thing was possible. He insisted that there must have been breaks in the cloud so that the R.A.F. could see the targets. His various experts advised him otherwise, but apparently he was furious at the thought.
All this we discovered after the end of the war, when German records of the meeting became available. Oboe had not only shattered the targets of Germany, but had also shattered German morale, it continued the process for the rest of the war, and was probably the most effective single instrument of warfare in our entire armoury.
It is interesting to note that the members of the public of Great Britain and the Commonwealth probably have no idea of the existence of Oboe, and have certainly never heard of Reeves, who invented it with the able assistance of Dr F.E. Jones, and a small team of enthusiastic ‘boffins’.
MacMullen, Bufton, Slim Somerville and the rest of the boys in the Oboe squadrons got their D.S.O.s and their D.F.C.s by the sheer weight of their obvious bravery on operations. The inventor of the equipment, however, got precisely nothing. What a grateful and gracious country we live in!
See D.C.T. Bennet: Pathfinder
NB: This is the original caption which gives a different date from Bennett for the first RAF ‘Blind bombing’ raid.