207 SQUADRON ROYAL AIR FORCE HISTORY
& The Wesseling Raid 21/22 June 1944
The background from the German side
The Editor: I can do no better than quote at length from Bill Gunston's classic book on the development of Night Fighters [Night Fighters - A Development and Combat History, Gunston, p103 onwards]:-
Superficially, the Ju 88G was immediately distinguishable from the other variants by its vertical tail, which was the larger, squarish tail of the Ju188. Poor directional stability and generally bad control qualities had been adverse features of the earlier 88C and 88R night fighters, especially when operating at maximum weight, as they nearly always did. In the first six months of 1943 more than 70 Ju88 night fighters had been written off as a result and with the steady attrition of the Luftwaffe's irreplaceable experienced pilots, the situation was getting worse.
The G, however, could be safely flown at all weights, even by a novice with only 150 hours. It finally eliminated the offset under-nose gondola and instead introduced a large cannon bulge under the mid-fuselage. This bulge was necessary because Telefunken had developed a new and more powerful Airborne Interception radar which needed the whole nose. It was Fu-G, Lichtenstein SN-2.
SN-2 was an odd and yet lucky choice (for the Luftwaffe). Its design had been started in late 1942, long before the RAF had played their high card and used WINDOW. It might have been expected to operate on shorter wavelengths than the previous sets, to use a smaller dish aerial, get better resolution, a concentrated beam and fine discrimination.
On the contrary, it used a longer wavelength, greater than 3 metres, which meant another cumbersome aerial array (called HIRSCHGEWEIH, "antlers") and a very long minimum range of some 1,200 feet. Maximum range was about four miles and the angular cover was excellent. However, for a long time the excessive minimum range was thought to be a great drawback, if not positive grounds for rejecting the set entirely.
It was only after the massive use of WINDOW had thrown the German night defence system into chaos that it was realised that SN-2 was a fully developed AI radar that was almost unaffected by the foil strips. Thanks to its long wavelength, it could still 'see' in the presence of dense WINDOW clouds, almost as well as before. Goering at once ordered a crash programme of 1000 sets from Telefunken and these were installed in both new and existing Ju88 and Bf110G night fighters. Soon the SN-2 was being supplemented by a simplified version of the old FuG 202 served by a single quad dipole aerial, to take care of the final closure to visual acquisition at around 300 feet range.
In the Autumn of 1943 the German night defence force stood at a crossroads. It had largely been reeling under crushing blows but had never failed to hit back hard - largely thanks to Hajo Herrmann and his infectious spirit of cool ferocity which relied on the unjammable human eye. With new sensors, the night defence force was on the verge of making a giant come-back and inflicting on Bomber Command losses so painful that, had the night onslaught not been switched to different targets for reasons connected with the forthcoming invasion, Bert Harris would have been forced to take agonizing decisions.
But at one stroke, Goering knocked the Defence Force askew again - he sacked Kammhuber. He had long thought Kammhuber's reliance on electronics to be nitpicking and tiresome; the debacle at Hamburg made the sacking inevitable. In his place he appointed Generalmajor Josef Schmid and though Schmid did his best, he was no long term strategist and could not plan as had his predecessor.
The rest of the Battle for Germany was an endless series of improvisations, with one inevitable outcome. At least as big contribution to that outcome (as from the RAF) was made by the US 8th Air Force in daylight, which not only gained air superiority all the way to its targets but also destroyed quite a few night fighters used by day because of their endurance.
Towards the end of 1943, Herrmann's single seat pilots had suffered sorely - far more in crashes than in combat - and no new experienced pilots were available to take their place. The few aircraft that were left carried NAXOS-Z and so did almost all the regular NJG fighters.
By the end of 1943 a majority of the twin engined aircraft also carried FuG 227 FLENSBURG. This was the passive receiver that homed in on the RAF bombers' MONICA tail warning radar. It worked like a dream. From now on the NJG crews cared little for WINDOW or close ground control. All they needed was some idea from the controllers of where the bombers were. The ZAHME SAU principle of looking for the WINDOW clouds paid off here. The loose freelancing technique became still looser, as the controllers merely gave a general running commentary, broadcast to all and sundry. The FLENSBURG/NAXOS-Z combination was amply good enough for a closure to visual range, but increasingly the SN-2 was also corning into use to make an interception still more certain.
Once the German night fighters could see their target, shooting it down had become considerably easier. They were using a new type of cannon installation which they called SCHRÄGE MUSIK."