Most Secret War

by R. V. Jones

  Reviewing therefore what we have seen to be reasonable extrapolation from present practice, a two-stage rocket of about 150 tons starting weight could deliver a I ton warhead to nearly 3,000 miles range, with a probable error of 10 miles in range and 3 miles in line. This might be a feasible weapon for delivering a uranium bomb, should such a bomb become practicable. It would be almost hopeless to counter by attacks on the ground organization, because the increased range would allow an almost unlimited choice of firing site, while the trajectory could be so varied that the firing point could not be deduced without sufficient accuracy for countermeasures. Production would probably take place underground. At the moment such a rocket could not be intercepted, but by the time it becomes a serious possibility it may itself be a target for smaller defence rockets fitted with predictors and homing devices: but these would depend upon adequate warning, and the defences might also be saturated by a salvo of long range rockets.

  The protagonists for the development of very long range rockets would probably have, in Britain at any rate, to meet the criticism that it would not be worth the effort expended. The A4 has already shown us that our enemies are not restrained by such considerations, and have thereby made themselves leaders in a technique which sooner or later will be regarded as one of the masterpieces of human endeavour when it comes to be applied to the exploration of Space. As it is mainly with our enemies that Intelligence is concerned, rather than with our own views on military economics, it suffices that the long range rocket can be developed much further. In the light of this fact, we must watch.

  CHAPTER FORTY-SIX

  V-3

  BEFORE ANY of the ski sites had been discovered in 1943, we had found some very large concrete constructions which from their deployment seemed likely to be used for launching missiles against London. Three of them, Lottinghem (behind Boulogne), Siracourt (near Saint Pol) and Equeurdreville (near Cherbourg), proved to be artificial caves for the assembly and launching of flying bombs. Another two, Wizernes (also behind Boulogne) and Sottevast (behind Cherbourg), were to serve a similar function for the rockets, and one at Watten (behind Calais) was to be both a rocket launching point and a sheltered liquid oxygen plant. Despite the huge amounts of concrete used, and although we were for a long time unsure about the exact functions of the individual sites, we felt that we could keep these structures from being completed, thanks partly to Barnes Wallis’ ‘Tallboy’ bombs.

  We felt the same way about yet another great concrete structure, that at Mimoyecques, near Calais. It was heavily bombed, and could probably never have come into action, but we did not divine its exact purpose until our forces overran it. Under the name of ‘HochDruck-Pumpe’ (High Pressure Pump) it was to contain 50 smooth-bore barrels approximately 6 inches (15 centimetres) in diameter and 416 feet (127 metres) long, firing finned projectiles, each weighing about 300 Ibs. at a combined rate of up to ten per minute at London. A final muzzle velocity of about five thousand feet per second was to be achieved by igniting further propellant charges in side ports up the main barrel, as the projectile passed them on its way out. The development of the scheme was pursued enthusiastically in Germany but, fortunately, it hit a basic snag: above about 3,300 feet per second the projectile became unstable and ‘toppled’, and thus fell badly short. This fact was only discovered after twenty thousand shells had been partly manufactured.

  When the purpose of Mimoyecques was appreciated in London there was, inevitably, a feeling that Intelligence had failed. Actually some of our sources had reported that it was a long-range gun, but since the ski sites were also sometimes described in the same way this evidence was inconclusive. The Intelligence techniques that had been successful against the flying bomb and the rocket appeared to have failed against HDP, and there had to be a reason. Basically it was that with our limited effort we had to concentrate on the most urgent problems, and thus on catching weapons not so much at the research stage (although we sometimes achieved this) as in the development phase—which usually meant when trials were showing promise.

  In the case of HDP the trials did not reach this phase: we discovered a letter from Professor Osenberg, who late in the war had been appointed to co-ordinate German scientific effort, to Martin Bormann, Hitler’s Deputy. The letter had been written on 8th May 1944 and clearly had embarrassed Osenberg, who had been deputed by two large conferences at the testing establishment at Misdroy on 22nd March and 26th April and by another in Berlin on 4th May, to inform Hitler that the trials had been a failure, and to deplore the waste of material and effort. It was later said that Hitler nevertheless ordered the construction at Mimoyecques to continue because it attracted bombs that might otherwise have been aimed at more vital targets. Actually, some improvements were made to HDP and in a much less ambitious form it was said to have been used against our land forces on the Continent in the winter of 1944/5. Had it approached a degree of success in trials comparable with that of V-1 and V-2, we should probably have heard something of it, and Mimoyecques would have been even more heavily bombed than it was. My contemporary conclusion on V-3 (26th April, 1945) was, ‘There was little warning: there was little danger’.

  A possible V weapon on which we received detailed information was a long-range glider bomb, the BV246. This had a range of about 200 kilometres when dropped from a height of seven thousand metres (23,000 feet) attaining speeds of about 350 m.p.h. at height falling to 250 m.p.h. at ground level, and carrying 430 kilogrammes of Amatol explosive. It was thus an early example of a ‘stand-off’ missile, along with the air-launched V-1; but although we were able to follow its development through the radar watch on the Peenemünde trials, it made no impact on the war.

  Other developments that the Germans had in hand at Peenemünde were the A9, a winged version of the A4 rocket, designed to ‘bounce’ on the atmosphere at re-entry so as to glide to an increased range covering most of England, and the A10, a two stage rocket to reach America. They also adapted their rocket technology to defensive missiles like ‘Wasserfall’, a ground-to-air missile, and the X-4 air-to-air wire guided missile. We had already seen two of their missiles in operation, the HS293 rocket-propelled glider bomb and the Fritz X guided ballistic bomb. With these developments, coupled with their advances in infra-red technique, the Germans could not substantially affect the outcome of World War II, but they initiated a new phase of warfare. Their most desperate proposal was a Kamikaze-type project to build manned V-Is to steer against vital targets; several hundred were manufactured, and about 100 pilots trained, but they were not used. The feasibility of such a project had been demonstrated by the courageous woman test pilot Hanna Reitsch, who actually flew a V-1 to establish the cause of its control troubles.

  Both in the air, with the ME262 jet fighter, and at sea with the ‘Schnorkel’ U-boats and the fast Walther U-boats propelled by hydrogen peroxide, and with new homing torpedoes, the Germans would have had an impressive armoury if they had been able to sustain the war for another year or two. Moreover, in the nerve gases, they had a weapon to which we would have had no counter; fortunately Hitler believed that we must have equally lethal gases available, and in any event the war situation changed so rapidly that he was not tempted to start gas warfare. On 22nd December 1944 I had to write an appreciation of the new German weapons for Churchill, on the basis of which he gave a warning to Parliament. My report concluded.

  The Germans have been consistently fertile in producing new weapons, and in several directions temporarily outshine us. The most notable examples are the new submarines and fuels, rockets, and jet propulsion generally. Few weapons starkly novel to Intelligence have been discovered during the past two or three months, but several of those previously discovered are only just coming into operation; if available in sufficient quantity, they would have a pronounced influence on operations. It is therefore production rather than invention, particularly of synthetic fuels, that is going to be Germany’s main difficulty.

  Fortunately for us, the production di
fficulties proved too great.

  CHAPTER FORTY-SEVEN

  Bomber Triumph

  AS THE war entered its last year, the Germans were feverishly on the defensive. They were bringing out so many variants of their basic radar systems—and copying some of ours—that I had written in March 1944 ‘In 1940 the Germans regarded radar as a means of economizing in Observer Corps. In 1942 they used it to economize in fighters. In 1944 all signs of economy have disappeared, and radar is becoming an end in itself.’ Even so, we were far from laughing at our opponents, for they were inflicting so many losses on Bomber Command that we were grateful for the respite offered when the Command was pulled back to bomb the Invasion targets.

  Possibly adapting the idea from the panoramic cathode ray tube presentation in our H2S bombing equipment, the Germans at last built some ground radar stations with large aerials continuously scanning all around them, under the code-name ‘Jagdschloss’ (Hunting Castle). Finding one of these in Denmark, I asked for a low oblique photograph; the sortie was flown by Wing Commander Donald Steventon, a close friend of Tony Hill who used to visit my office with him. The resulting photograph is shown at Plate 29a; it was one of the first taken with the forward-facing cameras that we had had so much difficulty in getting adopted, and it gives some idea of the improvement in definition. Also shown in Plates 29b and 29c are two German photographs of the presentation screen of a Jagdschloss when it was tracking one of our raids, which we were protecting with jamming (the radial streaks) and Window, which blocked out whole areas of the tube.

  During the spring of 1944 we continued to gather retrospective evidence regarding the losses caused by I.F.F. having been left on. In a single JagdDivision (JD2) the Germans credited it with 60 bombers by night and 150 by day during the first two months of 1944. Now that at last it was entirely switched off the Germans were puzzled, and there was one occasion, perhaps the ‘Köpenick Raid’ (p. 382) where an American raid was not intercepted because the Germans had been unable to locate it in its I.F.F. silence. But they were now prepared to listen for any radio or radar transmission that originated from British or American bombers, and they rapidly expanded their newly formed Raid Tracking Organization to exploit any weakness.

  Not only could German fighters be directed on to the track of air raids by information gathered by the new organization, but the fighters themselves were now equipped with special receivers to home from a considerable distance on to any transmissions that might come from radar equipment carried by the bombers. One of these latter equipments was ‘Monica’ which was installed in every bomber and which was designed to detect echoes from nightfighters approaching from the rear. But it proved, as it was bound to be, much more effective in giving away the position of the bomber to the fighter, than vice versa. Trials with the JU88 nightfighter that had landed at Woodbridge on 15th July 1944 (p. 393) showed that its ‘Flensburg’ detector enabled the nightfighter to home from a range of fifty miles to within a thousand feet of a bomber fitted with Monica. As a result the Commander-in-Chief ordered the complete removal of Monica. A corresponding detector ‘Naxos’ for our H2S transmissions could home from 40 miles, and so orders were issued for a minimal use of H2S in checking navigation and in finding the target. These orders could have been issued months before, simply on the basis of commonsense, but they had waited for a cast-iron Intelligence case in each instance.

  The return of Bomber Command to targets in Germany in the second half of July 1944 showed an immediate reward for our efforts. On 18th/19th July, the Command achieved complete surprise through radio silence in a raid on Scholven in the Ruhr; and on 23rd/24th July it lost only four out of 629 aircraft on Kiel, where the Germans—no longer able to spot our main force by its radio clamour—tried to intercept the spoof force instead.

  General ‘Beppo’ Schmid, who had succeeded General Kammhuber in command of German nightfighters in the previous autumn, now found himself in as great difficulties—though of a different sort—as his predecessor had. He recognized that he needed 200 kilometres of warning before our bombers entered Germany if his nightfighters were to intercept us effectively, and he had come to rely on listening to our superfluous radar transmissions for this warning, rather than on his own battered radar. Now, at last, our transmissions were being denied him despite the security measures that he took to ensure that no clue should be given us that the Germans were exploiting our transmissions so successfully. On 16th November 1944 I happily reported

  The difficulties of the Raid Tracking Organization apparently induced its commander to seek inspiration from his subordinates by a widespread appeal in the form of a competition essay. The subject matter of the essay, which was open to all officers, men, and women, of the German Y-Service, may give some indication of their recent lines of thought. The points to be considered were mainly the suggestion of new radiations from our bombers which might be utilized for early warning and recognition, and of methods whereby we might be induced to switch on existing radio equipment earlier in a raid. The above competition came to our notice through the misfortunes of a Y-Service company which since early September had been retreating through Greece to an ever-receding final destination. As it received by the same post a request for a return of the numbers of men taken prisoner, wounded, killed, and missing, the essay notice was probably treated a little flippantly. Only with difficulty could we restrain ourselves from entering in place of the unfortunate company; with luck, we should have won.

  Besides achieving radio silence, of course, we now had the advantage of occupying France and Belgium up to the German frontier, so our jamming aircraft could now operate much further forward, and blind the German long-range radars. The Germans had therefore to react very rapidly once they detected a raid approaching, and in the resultant hurry, they inevitably made mistakes, especially when we were encouraging them to do so by means of ‘Spoof’ raids in which a few Mosquitoes would drop so much ‘Window’ that they looked like a large force. On 6th November, for example, we made two main attacks against Gravenhorst and Koblenz, putting in a ‘Spoof’ force against Gelsenkirschen. Seven Gruppen were airborne against these raids, with two more at cockpit readiness; of the total of nine, five Gruppen were drawn against the ‘Spoof’ force.

  Besides providing diversions, ‘Spoof’ raids could be used to get the German nightfighters up, and so tire them, on nights when we were making no major raids. On 9th/10th November 1944, for example, although the Germans had originally thought that bad weather would prevent us operating, they were deceived into treating a ‘Spoof’ raid on Mannheim as a major one; and when they had unravelled the deception, they further deceived themselves by concluding that it must be the prelude to a major raid. As a result, aircraft of six Gruppen were airborne for 2½ hours.

  One of the examples that we enjoyed most occurred on 6th October 1944, when we obtained General Schmid’s personal reaction to the fact that our losses were only 13 out of 949 aircraft. The night’s major operations were twin attacks on Dortmund and Bremen. In the latter, our bombers made a low approach under radio silence, while the German early warning radar was jammed by a screen of 100 Group1 aircraft operating their ‘Mandrel’ jammers; as a result the nightfighters were only able to attack after our bombers had been over the target for ten minutes. Similarly, the Dortmund force flew low over France and turned north and climbed towards the Ruhr again screened by ‘Mandrel’ aircraft, while a ‘Spoof’ force of Mosquitoes went on to threaten Mannheim.

  The result was confusion to the defences, and General Schmid reacted with a castigatory diatribe to the whole German nightfighter organization: ‘I am astonished that in spite of pains, admonitions, and orders throughout the whole year, I have not succeeded in bringing the Jagd Divisionen at least to the point of being able to distinguish in what strength and in what direction the enemy is approaching. In my view, there is no excuse whatever for this failure.’

  We happily noted that his astonishment must have continued unabated, for he had no be
tter luck throughout October, as the following table shows:

  Date Main Targets First Plots Sorties Losses

  5.10.44 Saarbrucken Luxemburg 699 3

  6.10.44 I. Dortmund Bonn 949 13

  2. Bremen Terschelling

  9.10.44 Bochum Aachen 585 6

  14.10.44 1. Duisburg 2 mins after Target 1573 9

  2. Duisburg Target

  3. Brunswick 45 m. S. of Lippstadt

  15.10.44 Wilhelmshaven 60 m. N. of Groningen 674 11

  19.10.44 1. Stuttgart Metz 1038 9

  2. Stuttgart Metz

  3. Nürnberg Trier

  23.10.44 Essen 20 m. S. of Aachen 1197 8

  30.10.44 Cologne 1073 2

  31.10.44 Cologne Lille 658 3

  Our low losses could be attributed to the simultaneous operation of several factors. At last we had achieved radio silence, and at last we had effectively jammed all forms of German radar. We had pushed back the German night defences to the frontiers of Germany itself, which cut down their warning time, and the German nightfighters were now beginning to feel the shortage of petrol. All this gave scope which the Bomber Command tacticians exploited to the full. In addition, the operation of our long-range nightfighters now became a serious factor, and the German nightfighters began to sustain casualties so severe that they added an extra man to their existing crews of three, purely to divide up the radio and radar duties and to keep a backwards watch for the approach of our nightfighters. So we had the amazing situation of four men in a German nightfighter operating over Germany being harassed by two men in a British nightfighter operating from Britain.