Hitler's Revenge Weapons

by Hitler's Revenge Weapons- The Final Blitz of London (retail) (epub)

  The Wehrmacht launched their first V2s operationally on 8 September, Group North firing two at London from a site near The Hague, Holland, and Group South one against Paris from the Belgian town of St Vith, in the Ardennes. Learning from the past, the German launch crews were now mastering the art of camouflage and deception, maximising their ability to melt into the local environment to conceal themselves from the air, taking cover immediately any Allied air activity was suspected in their area and in any event as soon as they had fired their missiles, greatly enhancing their survivability. The Allies had few practical answers to this, one being to mount very expensive armed patrols over rocket-infested areas, in the hope of catching the enemy in the open, fleetingly, immediately before, during and after a launch, destroying them there and then. This was easier said than done, given the enormous area over which the fully mobile, transient V2 units moved. This could stretch from Scheveningen on the Dutch coast, across to the Rijsterbos in Friesland, then to Burgsteinfurt in Munsterland in Germany, down to Hachenburg, then west to Kottenforst, south-west of Bonn and on past Euskirchen to St Vith in Belgium, and up past Walcheren in Zeeland to the Hoek van Holland – but the area around The Hague remained the main hunting ground. There were reports of V2s being sighted as they rose from their launch pads, but some were suspect and only very rarely could successful attacks be carried out on the residual facilities which were slow to move. Neither radar, sound-ranging nor flash-spotting could do much to help find the rockets in such a wide area, and Bletchley was picking up very few tell-tale signals. Reliable information was rolling in from visual sightings by Belgian and Dutch resistance groups on the ground, pinpointing the rocket units and likely firing points, typically around the Rijksweg, Wassenaar and Duindigt districts of The Hague, and on Walcheren Island, but there could be no guarantee that these targets would still be visible, or even there, when bombers arrived; these were indeed fleeting targets.

  On 17 September Bomber Command reacted immediately to a report by Dutch partisans on a V2 supply unit in a wooded area south-east of Wassenaar, by sending twenty-seven Lancasters and five Mosquitos to attack with twenty-four 250lb marker bombs and 169 tons of high explosives – but they were too late; the unit had either left or was never there – and nothing was achieved. On the same day twelve Spitfires of 229 Squadron from Coltishall, looking for launch sites close to the Dutch coastline, spotted a V2 streak away after launch, but they were too far away to find the exact location. Sometimes, however, the Allies were lucky. Acting on information that General Kammler was visiting Walcheren on 18 July, to witness the launch of the first V2 from there to London, RAF bombers carried out a successful attack on its supply lines, which resulted in the cancellation of the second round of firing scheduled that day. There was more evidence that attacks on V2 logistics targets were paying off when it became known, on 22 September, that Generals Kammler and Dornberger were concerned that the supply of liquid oxygen to the front line had been reduced to 200 cubic centimetres per day, enough to launch only twenty-four rockets a day.

  Meanwhile, the burgeoning success of the V2 campaign in the autumn of 1944 was causing great concern in London, and specifically at Fighter Command HQ, Stanmore Park, where Air Marshal Sir Roderick Hill was primarily responsible for airborne countermeasures. With the agreement of his colleagues, the Chief of the Air Staff and Air Chief Marshal Sir Arthur Tedder, Eisenhower’s deputy (Air) as Suprreme Commander Allied Expeditionary Force, his fighter-bombers would attack any V2 target on sight, provided there was little or no danger to the local civilians. Also, his UK-based aircraft would, on a case-by-case basis, be authorised to pick up fuel at RAF airfields in liberated Europe, to enable them to carry out longer, more heavily-armed sweeps over rocket-infested areas. In November 2TAF fighter-bombers were cleared to do likewise and were blessed with early success against two trains moving to their launch areas carrying a total of forty V2s.

  On 21 November, the latest CROSSBOW report from Duncan Sandys reflected the difficulties of finding and destroying rocket targets, inter alia admitting that the most important target of all, the massive Mittelwerk missile factory, some 300 feet below the Harz mountains, which was then producing thirty V2 a day, many V1s and other war assets, was all but invulnerable – even to the 12,000lb Tallboy seismic bombs. Also, it was now generally accepted that the transient Group North, located variously at Kleve and Burgsteinfurt on the Dutch/German border, had learned how best to operate relatively freely from the area surrounding The Hague, firing at London, while Group South, operating in the Euskirchen-Koblenz region, was doing likewise against targets in Belgium and France. On the table now was the unpalatable proposition of using heavy and medium bombers, at high and medium levels, albeit with their inherent inaccuracies, against rocket units buried in heavily populated areas around The Hague.

  From the beginning of 1945 six Spitfire squadrons from Fighter Command acted as fighter-bombers against the elusive rocket launch sites in West Holland, and initially they enjoyed some success, but in February, when Flak Batteries 1/485 and 3/485 deployed to Duindigt, north of The Hague, the V2 launch rate increased. Almost in desperation it was suggested that AA on the east coast of England put up a screen of shrapnel into the expected path of an incoming rocket – but this idea was quickly rejected.

  However, such was the clamour in London that the capital was having to bear too much of the pain that, at the end of January, the Defence Committee eventually agreed that the Haagse Bos, a wooded area, close to The Hague, which was thought to be hiding V2s, be attacked on 3 March, by a strong force of fifty-six 2TAF medium bombers. This ended in disaster, an error in the mission briefing or navigation resulting in the lead bombers dropping their bombs on the south-east of the woods, rather than the south-west, causing a fire storm in Bezuidenhout, a district overflowing with refugees from Wassenaar, which had been cleared by the Germans for their rocket operations. As a rough estimate, 500 civilians were killed, with 12,000 losing their homes and all their possessions. The tragedy seemed all the greater when it was found that the rockets said to be in the woods, had been moved out more than a week before. The inevitable court of enquiry blamed inadequate intelligence, mistakes by individuals and a failure of the staffs at 2TAF to learn from earlier sorties flown by Fighter Command. Those who had argued against this type of attack around The Hague had been right – and there would be no more raids of this kind in that area but fighter-bombers and armed reconnaissance aircraft would continue to play their deadly game of cat and mouse with the V2 rockets – a game neither player could win outright.

  Then came another problem. Between midnight and 06.00 on 3 March launch crews of Flak Regiment 155 (W), deployed tactically in west Holland, fired thirty of its longer-range V1s at London, only two of which crossed the coast into England, and only one of these landing in Bermondsey, Greater London. Four days later RAF reconnaissance aircraft found two of the new launch sites, one on the airfield at Ypenburg and a second in a soap factory at Vlaardingen – relatively easy targets for the Spitfire fighter-bombers.On 8 March a platoon of Artillery Battery 3/485 fired its last V2s at London, one finding its mark on Smithfield Meat Market, with devastating results (Chapter Seven). In London John Mapplebeck reported that the sixty-five V2s hitting London that week showed a steady improvement in their accuracy – but it had all come too late.

  The RAF fighter-bomber squadron commanders were now being given some discretion in the planning of their attacks, the charismatic commander of No.602 Squadron, Max Sutherland seizing the opportunity to do so when the Dutch Resistance reported that the Shell Mex Building in The Hague had become the HQ for the V2 operational staff, and his squadron was tasked with its destruction. He found that the width of the building, from his preferred direction of attack, equated to the wingspans of five of his Spitfire XVIs, line abreast, in which formation they would approach at rooftop height, with all cannon and machine guns blazing, to deliver their 250 and 500lb bombs, as they came within range. The risks were h
igh, with intensive AA of all calibres to be expected at all points from landfall at Den Helder and thereafter as they departed over the Scheldt, but so were the potential rewards, and permission was given to proceed. No.453 Squadron from RAF Ludham would attempt to distract the enemy with a simultaneous attack nearby. The raid took place on 19 March 1945 and it went to plan with none of the aircraft lost. Max Sutherland’s Spitfire did take hits as he pulled up rather imprudently to look back, with great satisfaction, at the Shell Mex building – now shrouded in smoke and dust, but he was able to limp on to their refuelling stop in Belgium. Among his pilots on that day was Flight Lieutenant Raymond Baxter, who would go on to become a prominent commentator and presenter for the BBC. ‘Bax’ remembers the moment that they roared over the roof of their target, at 400 mph, to be confronted, dead ahead, by a seemingly huge black cockerel, mounted on a weather vane on top of a church steeple, only his instinctive reaction saving the day by what must have seemed inches.

  For the last eighteen months CROSSBOW operations had attempted, with only limited successes, to destroy or at least minimise the capability for the Wehrmacht to employ their flying bombs and rockets against the Allies. The manifold problems they faced have been well rehearsed above, and the costs were very high, not only in the diversion of air power from other wartime needs, but in military and civilian lives and material. There was, of course, no alternative but to use all possible means to protect the British homeland, a vital American stepping stone to the continent of Europe and launching point for the huge invasion forces poised to strike, and there could be no question of waiting for the final solution, that of occupying the missile sites. In February 1945 Hans Kammler, latterly in charge of all flying-bomb and rocket operations, gave some credit to the defenders, while noting the general impotence of Allied airpower:

  The counter-measures of the enemy increased considerably, especially as far as bombing and attacks by fighter-bombers were concerned ... . Supply lines were broken 44 times ... . This damage was remedied very quickly ... so that contrary to enemy air force statements reporting success, only negligible disturbance occurred, but never any definite stoppage in launching. From time to time it was necessary to stop operations during the day and launch only at night.

  Perhaps the real truth lies somewhere between the two perceptions?

  Chapter 9

  Hochdruckpumpe – And What Next?

  Before 1943 little was known about the third of Hitler’s vengeance weapons, the Hochdruckpumpe (HDP), ‘ High Pressure Pump’ - V3, but, had it become technically viable and operational earlier in the war, it could have added significantly to the Allies’ problems, particularly with the impending invasion of France. The V3 was a massive super-gun, designed to fire high-explosive projectiles at London from a site close to the French coast. This multi-charge gun, to become known as ‘The London Cannon’, was the brainchild of August Coenders, a German artillery engineer working with the firm of Röchling-Stahlwerk AG. With an aerodynamic ‘arrow-shell’, Coenders sought to achieve an unprecedented muzzle velocity of 5,000 feet per second, or Mach 6, a speed which would give it a range of 100 statute miles, just enough to reach London. Made of chrome nickel steel, the 7-foot-9-inch finned projectile, weighing 310lb, and carrying an explosive charge of 55lb, was fired initially from the breech of 6-inch diameter and 490 feet long, smoothbore barrel. It was then accelerated up the barrel by a series of solid-fuel rocket booster charges, ignited electrically within each of sixteen pairs of diametrically-opposed lateral chambers, as the projectile passed up the central tube. Fins on the projectile imparted the necessary spin in flight, as rifling does for accuracy in the conventional shell or rifle bullet.

  The first tests on the HDP, carried out in 1943 at the Hillersleben artillery range, Magdeburg, Germany, revealed problems in the projectile’s design and the ignition of the rocket boosters, achieving muzzle velocities of only 3,300 feet per second – far below expectations. However, Albert Speer believed in the gun’s potential and, having convinced Hitler that the project was worth pursuing, obtained his authority to carry out launch trials with a full-scale weapon at Misdroy on the Baltic island of Wolin. The redesigned projectiles, tested there between May and July 1943, increased the maximum range to fifty-eight miles before the gun destroyed itself – but still the trials continued. In March 1944 the HDP become the responsibility of the HWA, the Weapons Procurement Office, eventually joining the V1 and V2, under the control of Hans Kammler.

  Meanwhile, the Führer had ordered the construction of two huge reinforced-concrete bunkers, deep underground in the limestone hill at Marquise-Mimoyecques, just south of Calais, and 103 miles from London. The two bunkers of Fortress Mimoyecques, codenamed Wiese (Meadow), were to be one kilometre apart, each to accommodate five batteries of five super guns, a total of fifty. They would be constructed by the German Todt Labour Organisation, employing German specialists, local French and Italian ‘volunteers’, all well separated domestically from the Soviet and Polish slave labourers, half of whom would not survive the project. Work on the site began in September 1943 and went on twenty-four hours a day, in two shifts, each of up to 1,500 men, initially to build the two tunnels, 100 feet below ground and 650 yards long, to serve a vast network of galleries and shafts, ultimately to be manned by a garrison of some 1,200 men from Artillerie Abteilung 705. In galleries 300 feet below the surface, the ammunition would be fed into the guns, which were all inclined at 50 degrees and pointed at London, protected on the surface by steel plates, 10-inches thick, laid on 16 feet of reinforced concrete. The target date for completion of the basic facility was December 1943, with the first cluster of five guns to be ready for action by March 1944, and twenty-five (half the planned total) by the following October.

  Given that the visual clues to the existence of the bunkers were confined to twin rail lines vanishing into the Mimoyecques hills and a great deal of activity at the tunnel entrances, this might, at first, have generated only passing interest within an Allied intelligence community as it concentrated on the work in progress at the many V1 and V2 sites in the region. Indeed, it was not until 18 September 1943 that the photographic interpreters (PIs) at the CIU began to look more closely at the photos and, sensing something rather different, sounded the alarm. Sufficient evidence was then gathered, in short order, to justify two big CROSSBOW raids against the site.

  Hochdruckpumpe on trial at Hillersleben Range, Magdeberg, Germany, 1943. (Courtesy Mimoyecques Museum)

  The ‘London Gun’ lay deep underground in the limestone caves at Mimoychecques, south of Calais. (Author’s Collection)

  Now the only entry/exit to the Mimoyecques underground museum. (Author, Courtesy Mimoyecques)

  The only way into Fortress Mimoyecques. (Author, Courtesy Mimoyecques)

  An early version of the Hochdruckpumpe in the underground museum at Mimoyesques, the booster chambers set here at 45 degrees, abandoned in favour of 90-degree settings. (Author, Courtesy Mimoyecques)

  Five metres of reinforced concrete, topped by 20cm thick steel plates, protected the five muzzles of each HDP cluster. (Author, Courtesy Mimoyecques)

  On 5 November 1943 (‘Fireworks Day’ in Britain!) a huge force of No.2 Group Bostons and Mitchells was tasked against the excavations at Mimoyecques without revealing the nature of the target to the crews. Bad weather caused the Bostons to abort, but forty-eight Mitchells, using Gee, continued to France, where they were escorted by eighteen squadrons of Spitfires. As they approached the target they were greeted by heavy flak but no German fighters, and the first twenty-four Mitchells dropped 187 500lb HE bombs on the target, the second twenty-four missing the aiming point by 400 yards. As soon as it became clear that very little, if any, damage had been done to Fortress Mimoyecques, heavy raids were repeated on 8 and 9 November, using different tactics but again without achieving any significant damage.

  The seismic effects of 617 Squadron’s 12,000lb ‘Tallboy’ bombs undermined the Hochdruckpumpe’s concrete structure,
causing flooding below ground at Mimoyecques. (Courtesy Mimoyecques)

  Meanwhile, the Germans continued to have problems with the gun undergoing trials in Germany and it was these problems which probably explained why work on the second bunker was abandoned late in 1943 rather than any damage which might have been caused underground by the November raids. The London Cannon now consisted of only twenty-five guns, and a further reduction to fifteen installed in three banks of five, was ordered in the spring of 1944. The remaining site was raided again, twice in March, four times in April and three times in May 1944, causing peripheral damage above ground but again with no evidence that the work underground was affected. Following D Day on 6 June, attacks on Mimoyecques were stepped up, with three raids that month, depositing 1,400 tons of high explosive bombs on the site, and when it seemed that the new weapon was about to become operational, two massive raids were planned for the 6 July. That morning, 100 Halifax heavy bombers delivered 464 × 2,000lb bombs, and in the afternoon sixteen Lancasters of the legendary 617 Squadron, led by Wing Commander Leonard Cheshire, each dropped a 12,000lb Tallboy bomb on the site, with great accuracy, leaving huge craters on the surface. What the Allies could not have known at that time, was that the seismic effects of the Tallboy explosions had led to the collapse of several arches at the 100-foot level, blocking the gun chambers and causing some flooding –with the result that the Germans decided to abandon Fortress Mimoyecques.