by R. V. Jones
Estimate Fact Remarks
Type of Propulsion Probably Rocket T & Z used somewhere. Argus Tube T–& Z–Stoffe used for starting.
Weight Warhead 1000–3000 lb. 2000 lb. (1,800 lb. H.E.) Estimate later finalized at 1 ton.
Speed Varying between 200 & 400 m.p.h. Varying up to 400 m.p.h. German intention 370 m.p.h.
Height Generally about 6,500 feet, but sometimes as how as 1,500 feet. 1,000–4,000 ft.
Range Generally 120–140 miles. Maximum 155 miles. Generally 120–140 miles. Maximum 155 miles.
Wing Span Probably 19–22 feet. 17 ft. 4½ ins.
Length Probably 17½–20 feet. 25 ft. 4½ ins.
Root Chord Probably 4–5 ½ feet. 4 feet.
Control Magnetic. Magnetic.
As regards the operational intentions, the ski sites were of course knocked out by our subsequent bombing; but I have the statement by Colonel Eberhardt, Wachtel’s Chief Technical Officer, regarding what was intended, and the comparison is as follows:
A.D.I. (Science) Eberhardt
Capacity of site 20 20
Maximum rate of fire 1 in 30 mins. 1 in 30 mins.
Time to fire all stored missiles 10 hours 10 hours
Replenishment period 2 days 1½ days
Total number of sites operating in one attack 50–100 64
The biggest mistake in my estimates concerned the nature of the propulsion. I had thought that this would be a rocket, and we had no idea concerning the ingenious nature of the engine until the campaign started. It involved simply a tube supported above the body of the bomb, with a combustion chamber at the front end. Air entered through the series of slats which acted as valves at the very front of the tube, and these slats closed automatically when the fuel was exploded in the chamber. The exploding gas drove a pressure wave down the tube and emerged at the rear end, which was open. The over-shoot then caused a partial vacuum at the rear end of the tube, and this started a pulse of rarefaction which travelled back along the tube to the combustion chamber. The consequent lowering of pressure there caused the valves at the front to open and a new charge of air was sucked in, and the cycle started all over again. It was like a large organ pipe with a valve at the front end, emitting an enormous sound for which the energy was provided by the combustion of the fuel, and the forward drive came from the reaction as the hot gases were pulsed backwards out of the end of the pipe. The engine was developed at the Argus Works, which were mentioned in my report as one of the seats of production, but none of us had any idea that a completely new engine was involved. The idea itself was not new: it had been partly developed as early as 1929 by Paul Schmidt and it had been at first financed jointly by the Army Weapons Office and the Luftwaffe. After 1934 it had been taken over completely by the Luftwaffe: and intensive development in 1942 enabled it to power the Luftwaffe’s upstart rival to the Army’s A4 rocket.
I had expected the engine to be a pure rocket, driven by decomposing hydrogen peroxide; and I had been more than usually pleased with the way in which I had been able to reach this conclusion. Since it involves an important point of principle it is worth recounting. When I saw the plans obtained for us by Michel Hollard, there was one building that was labelled ‘Stofflager’ which may be interpreted as ‘fuel store’. It was of unusual construction, since it contained two compartments, but there was no communicating door between them. Each compartment had its separate door to the outside; and although these doors were adjacent, they were carefully separated by a blast wall. I therefore deduced that two fuels were involved, and that someone had taken great care in the design that the two should not come into premature contact. I already knew of two liquids used by the Germans in the rocket-propelled glider bombs they had been using against our ships. These were hydrogen peroxide and sodium permanganate, and these were known to the Germans as ‘T-Stoff’ and ‘Z-Stoff’. I therefore conjectured that the Stofflager was intended to hold supplies of hydrogen peroxide and sodium permanganate. Following the same line, I found that some of the very squads that had been handling these materials for KG100 had been drafted to Wachtel’s organization. The case for believing that hydrogen peroxide and sodium permanganate were involved therefore appeared complete, as indeed it was. I worked out the volumes of the two compartments, and found that they were big enough to store enough of the chemicals to provide fuel for twenty flying bombs and give them the necessary 200 kilometres’ range for London. Moreover, I searched the site for any other building that might store some other kind of fuel, and there was none.
In view of all this reasoning, it was undoubtedly the simplest hypothesis to assume that the flying bomb would be driven by a larger version of the hydrogen peroxide rocket that we had previously seen in the HS293 glider bomb. Although this was the simplest hypothesis consistent with the facts, it turned out to be wrong. The bombs were driven by the Argus engine, which used a simple fuel like paraffin, and they came up to the ski sites already fuelled from the base depots. Hydrogen peroxide was undoubtedly used, but the purpose was different. It provided the steam power for launching the bombs from their catapults—a variant of the old ‘atmospheric railway’ which was after the war adopted by the British and American Navies for launching aircraft from carriers.
What I had done, after congratulating myself on spotting a clue that nobody else had seen, was to employ the principle known as Occam’s Razor: essentia non sunt multiplicanda praeter necessitatem (hypotheses are not to be multiplied without necessity). For if you start allowing more complicated hypotheses than are essential to explain the facts, you can launch yourself into a realm of fantasy where your consequent actions will become misdirected. As one of my academic colleagues once put it to his pupil: ‘If I tell you that the explanation of why I never see a tiger when I open the door is that there really is a tiger outside but that the tiger is frightened of me, so that every time it hears me opening the door it runs away and hides round a corner, you would say that I was mad—or, at least, a little peculiar!’ Time after time when I used Occam’s Razor in Intelligence it gave me the right answer when others were indulging in flights of fancy leading towards panic. But every now and again it will be wrong, as it was on this one occasion in my experience. By accident you may just have collected a set of facts that can be explained by a simpler hypothesis than what is really occurring; the answer is never to be satisfied but always to search for fresh facts and be prepared to modify your hypothesis in the light of those facts. But in general Occam’s Razor gives much the greatest chance of establishing the truth.
As it turned out, the mistake was of no consequence, for the operational deduction was that we should try to knock out German hydrogen peroxide production, and had we been successful in this, the V-1 campaign would have been paralysed because there would have been no way of launching the flying bombs.
The vital performance figures were correct, of course, and they provided all the information that would be needed for countermeasures. To intercept the flying bombs, the performance of our fighters would need to be increased. To engage the bombs our anti-aircraft guns would need new predictors and proximity fuses that would have to be set sensitively enough to work on the relatively small targets that the bombs themselves presented. And all this information was available six months before a flying bomb was launched against London.
Finally, despite the overwhelming preoccupation of the radar stations with plotting the flying bomb trials, my report warned that the rocket should not be forgotten, for the stations were trying to plot the rocket trials, too, although these were far less frequent.
Long after the war, one of the members of the Committee that the J.I.C. had set up, Matthew Pryor, most generously wrote (in The Times, 19th April 1961): ‘The debt the country owes to Dr. Jones’ brilliant, if rather lone-handed, Intelligence work cannot be over-estimated’.
But in reality I was far from alone: What could I have done without the devotion of men like Bimbo Norman and Claude Wavell to their respective tasks, the pilot
s like John Merifield, and the men and women in the field who faced torture like Christiansen, Hollard, Comps, Marie-Madeleine and Jeannie Rousseau? Or without the backing of men like Hugh Smith and Charles Frank, who also stood ready to take over if I became a casualty? We were part of a great team in which we all knew our parts; from past experience we had confidence in one another, as for example between Peter and ‘Pop’ Stewart and me, to know that the best hope of solving the problem lay in our continuing to work together, whatever other arrangements might be imposed. If ‘brilliant’ is a fitting adjective, it applies to the whole team and I was merely that part which took the fewest physical risks and yet—as Churchill said of himself—had the luck to give the roar.
Just as my report was completed, the first active countermeasures—the bombing of the ski sites—started on a large scale on 21st December 1943. Here the American Eighth Army Air Force came fully to our aid, and on Christmas Eve put out its greatest effort ever—thirteen hundred aircraft dropping 1,700 tons of bombs. Wachtel decided that we knew too much about his organization, and tried to throw us off the scent. As I first heard the story, he aimed to suppress the name ‘Flak Regiment 155(W)’ and replace it by ‘FlakGruppeCreil’, pulling back his headquarters 100 kilometres southwards from Doullens to a château near Creil, about 45 kilometres north of Paris. To change his personal identity he dyed his hair, grew a beard, and changed his name to ‘Max Wolf’. The whole move was carried out in secret, even to the extent of his entire headquarters staff driving into the back streets of a town and re-emerging on the other side in different uniforms and with different transport. In this it was reported to have been so successful that its laundry never again caught up with it. But we were quickly informed, because we received the following report, dated the end of December 1943:
Following numerous air reconnaissance flights and bombing, the H.Q. of the A.A. “WACHTEL” regiment was transferred from DOULLENS to a chateau in CREIL region, exactly 55 Km. from PARIS, and in the immediate vicinity of a small town indicated in German by the initials: “M.b.B.” that is to say: “Ms.B.” or “M.e.B” (MARCQ-en-BAROEIL?). The transfer was made under conditions of the utmost secrecy; the H.Q. Staff believe that the emplacement is still unknown as there has not yet been any reconnaissance from the air.
However, the unit keeps at DOULLENS an important relay-station called “Dohle” in telephone conversations; the “WACHTEL” regiment is called “Flakgruppe Creil” in the Army telephone organization. The totem of the regiment is:
Fig. 23. The symbol for Wachtel’s Regiment that was never used
which is made from the C.O.’s name.
The full Staff is expected at H.Q. for the beginning of January; it comprises 20 officers. Colonel WACHTEL himself will not be in continual residence at his H.Q., for he goes on inspection missions in BELGIUM and also makes frequent journeys to PARIS, BERLIN, ZEMPIN, to supervise the finishing touches to the stratospheric rocket. It is reported that the platforms are ready and the personnel standing-by, but the guns will only be set up on their emplacement in March.
The officers of this unit expect a Commando raid or even a landing having for mission to prevent the use of this weapon. The CREIL H.Q. is said to be very strongly defended (electric network, constant patrolling, A.A. Defences always at the ready).
It is reported that GOERING’s and even HITLER’s visit is expected in the near future.
It might be possible for an interpreter in charge of the purchasing for the account of the unit, and acting as liaison with the French authorities, to gain access into the H.Q.
Who had written this report? Again it was one that I remembered long after the war because of the pun in the ‘totem’, since the German for one-eighth is an ‘Achtel’. At a reunion in 1955 I met one of Wachtel’s officers, and congratulated him on the regimental sense of humour in choosing such a sign for its escutcheon. He was astounded, and asked, ‘However did you know that? We were going to use it, but we decided in the end that it was so obvious that it could not be used, and we were ordered not to mention it again!’
I could not tell him how we knew because I did not know—then. But after I met Amniarix I looked up the report again: it bore all the stamps of her marvellous handiwork and virtually identified her in the last sentence. She has confirmed that the report was hers, and also that she sent others which neither of us could identify. The puzzle is why she spoke of the ‘stratospheric rocket’ with such circumstantial detail in place of the flying bomb, because she was punctilious in reporting things exactly as she heard them, even when they made no sense to her. Watchtel and his officers could not mislead her when it came to organizational matters, but is it possible that they had hit on Cherwell’s very plan of using the rocket as cover for what they were really doing? Be that as it may, Amniarix’s reports stand brilliantly in the history of Intelligence; and three concentration camps, Ravensbrück, Königsberg (a punishment camp), and Torgau, could not break her.
CHAPTER FORTY
The Americans Convinced
THE AMERICAN commitment in Britain had been steadily growing during 1942 and 1943. Its impact on Intelligence was perhaps most directly felt in photographic reconnaissance, where an American unit was attached to R.A.F. Benson, and where American pilots in P38s (Lightnings) were now flying regularly. For some reason that we never discovered their casualties were substantially higher than our own pilots flying Spitfires. I thought that this must be due to a difference in speeds but this turned out not to be so. I remember the episode particularly because it brought me into warm contact with the American Commanding Officer, Colonel Hall, a quiet friendly airman who won my respect by flying the first American photographic sortie himself, exemplifying Xenophon’s dictum: ‘there is small risk a general will be regarded with contempt by those he leads if, whatever he may have to preach, he shows himself best able to perform’.
In the radio war, American participation was less direct, for it concentrated on the countermeasures side and left the Intelligence to us. In fact one American Naval Intelligence Officer, Commander Kearley, not only told me that he intended to depend entirely on us, but asked me to put a legend at the head of all our reports stating, ‘This Report is not to be reproduced except in entirety’. He was particularly concerned with radar Intelligence leading up to the landing in Normandy, and I was looking forward to a warm post-war friendship. But, in the same mould as Tony Hill, he felt that he ought to go on the D-Day landings and he was among the many who died on Omaha beach.
On the countermeasures side, an officer of the United States Navy, generally Captain (later Admiral) Solberg or his Deputy, Commander C. G. Mayer, regularly attended meetings of the Radio Countermeasures Board right through 1942 and 1943: and, following a visit to Britain by Dr. C. G. Suits, afterwards Director of the General Electric Company’s Laboratories at Schenectady, a strong team of American scientists and electronic engineers was attached to the Telecommunications Research Establishment at Malvern. The first Head of the team was Dr. V. H. Fraenkel, who then went on to General Spaatz’s Staff and was succeeded by John N. Dyer. As the U.S. Eighth Army Air Force grew in strength it became of course acutely interested in what we knew about German radar, and we found that the rivalry between the U.S. Army and the U.S. Navy was even greater than that which we had sometimes experienced between our own Services. Fortunately, there was a freemasonry among scientists that usually enabled us to sort any problems out.
Besides our co-operation in scientific and technical matters, where the superiority of American production engineering was often a powerful—even vital—aid, we also shared our experiences in Operational Research. One salutary incident that I recall concerned a British mathematical physicist and an American theoretical physicist, Dr. Charles Kittel, who had been set together, side by side, to work on the problem of deducing the characteristics of German magnetic mines laid at sea, especially the sensitivity and polarity of the firing mechanism. The data from which the characteristics were to be deduc
ed were the reports of our minesweepers as they exploded the mines, with the positions of the explosions being reported as ranges and bearings from the minesweepers. The first thing that Kittel wanted to do was to take a few trips on a minesweeper to sample the data for himself. The British theorist refused to do this, on the argument that he could only make a few trips, and therefore any experience so gained might be heavily biased, and therefore much too dangerous as a basis for generalization. So he stuck to his desk while Kittel went out minesweeping. What Kittel immediately found was that the reports from the minesweeping crews were wildly inaccurate as regards both range and bearing, and the only item of data on which one could rely was whether the mine had exploded to port or starboard. Simplifying all the later reports down to this extremely limited observation, he nevertheless succeeded in deducing the answer; but the British theorist went on accepting the data as accurate and never reached an answer.
The incident shows the importance of personal reconnaissance before taking a decision. Kittel had exemplified exactly what Isaac Newton had said in a letter to Nathaniel Hawes:
