by John Nichol
On 5 June 1944, the day after the Allies had entered Rome, the squadron’s endless rehearsals came to an end with confirmation that D-Day – Operation Overlord, the invasion of Normandy – was set for the following day. If there was disappointment that 617 would not have a more active involvement in D-Day, the crews were assured that their role was nonetheless an absolutely crucial one, a message reinforced by Leonard Cheshire in their final briefing.
‘The waiting is over,’ he said:
Not just the period of the recent training through which we have all been, but also for the years we have fought our way to this day. This is possibly the most crucial operation this or any other squadron has ever been called upon to perform. Our efforts tonight will not be of the usual destructive nature, but our successful endeavours will undoubtedly save hundreds of Allied lives this night, and possibly thousands in the weeks to come … Aircraft of the Second Tactical Air Force will sweep up the Seine soon after dawn tomorrow and break all the bridges between Le Havre and Paris, effectively isolating the large German armies in northern France, which our operation tonight is designed to hold in position in the Pas de Calais. I have not the slightest doubt about the successful outcome of tonight’s sortie. Thank you gentlemen, and as always, the best of luck to you all!18
‘There was real excitement’ at the news, John Bell says. ‘The invasion was happening and we were part of it! Everyone was keyed up in preparation and raring to go, but we had to get it right because thousands of lives depended on it. We all understood that at the time.’
Allied bombers had already been pounding gun batteries and radar stations along the entire French coast, trying to avoid revealing the true focus of the impending attack by inflicting equal damage on areas far from Normandy. A thousand aircraft were involved in D-Day operations that night, and the fuselages and wings of all Allied aircraft, including 617’s, were painted with black and white stripes, like a piano keyboard, to minimise the risk of losses to ‘friendly fire’, since the volume of D-Day signals traffic was certain to swamp the normal IFF (Identification Friend or Foe) system that used a transponder to identify friendly aircraft to British radar. Bomber crews were also forbidden from jettisoning bombs over the Channel that night, because of the significant risk of hitting one of the hundreds of Allied ships making the crossing. To reinforce Operation Taxable’s simulation of an invasion at close to the Channel’s narrowest point, hundreds of fake aircraft, landing craft and military vehicles had been assembled in Kent for the benefit of German air reconnaissance and spies. All was now in readiness for the grand illusion to be created.
‘Although it was the invasion, we were not thinking about the end of the war,’ one of the 617 Squadron pilots later recalled. ‘Just that this was a huge step forward in the course of the war, possibly a defining moment in what the future might hold. But we certainly weren’t talking about “the end”.’19 Les Munro was the first 617 Squadron pilot airborne at 23.05, with Cheshire and the other six aircraft of the first wave just behind him. They rendezvoused with the surface craft just off the south coast. The eighteen ships – harbour defence motor launches and search-and-rescue pinnaces – towing barrage balloons behind them and broadcasting sound effects and using radar counter-measures to strengthen the deception, began steaming slowly towards France. Meanwhile, 617 Squadron’s Lancasters flew overhead, travelling at a precise speed and height – 180 miles an hour and 3,000 feet – in line abreast with a separation of two miles between each aircraft. They held their course for exactly two and a half minutes, dropping their Window – the strips of aluminium chaff were 6 feet long and tied in bundles of 100 – at the rate of one bundle every four seconds.
They then performed a slow ‘Rate One’ turn lasting one minute, dropping no Window whilst turning, and then resumed dropping on the slightly shorter, two minutes and ten seconds leg back towards the English coast, before turning again, overlapping their previous track. Each completed circuit advanced them a little further towards France – one mile every six minutes and forty seconds – keeping pace with the ships below so that, seen through German radar, a huge convoy of ships appeared to be crossing the Channel towards Cap d’Antifer, just north of Le Havre, at a speed of 8 knots.
With a double crew and boxes and bundles of Window of different sizes stacked in every available space, each aircraft was very crowded. There was a red and green light operated by the navigator which told those dropping Window when to start pushing the bundles out and when to stop. When the next person took over, it had to be carefully coordinated so there was no pause or change in the rate the bundles were being dropped. Progressively larger bundles of Window were used as they flew nearer to the French coast, producing the increasingly strong radar signal that the Germans would have expected from an approaching fleet. All the time the navigator was keeping up a constant stream of instructions to the pilot: ‘Tighten the turn, you’re two seconds slow … You’re three feet too low. On course, on course. Begin to turn … Now! Ease up, you’re three seconds too fast.’20
Operation Taxable continued for four hours, and the work of dumping the Window down the flare chute was so gruelling that each Lancaster’s double-sized crew – fourteen men – took turn and turn about. The intense concentration required of the pilots and navigators, who had to keep within four seconds elapsed time and five feet of altitude at all times, meant that they were also ‘spelled’ by replacements. As the first wave of eight Lancasters ran short of fuel and Window, a second wave of eight replaced them. German radar picked up the ghost fleet, and confirmation that they had bought the deception was offered as some of the shore batteries began firing on the non-existent invaders. In the final stage, the ships ran in fast to within a couple of miles of the shore, simulating a landing attempt, and then retreated under cover of smoke, laying mines behind them.
Just before the dawn light that would expose the hoax to the German gun batteries preparing to open a barrage of fire against the phantom invasion fleet, the Lancasters and their attendant ships headed for home. 617’s men had to keep below 1,000 feet, since the skies above them were thick with outward-bound bombers, fighters, and gliders carrying assault troops. On the surface of the sea below them, they could also see that the Channel to the west was black with ships making for the true invasion sites on the Normandy beaches. ‘As we headed back, D-Day was under way,’ John Bell says, ‘and there was a real sense of a momentous day and great excitement – if the invasion was happening, then we really were on the front foot. But we still had no idea how long the war would go on for. Not a clue.’
Several other simultaneous deception exercises had also taken place that night. Operation Glimmer was a similar Window-dropping exercise carried out by 218 Squadron and six motor launches, simulating an invasion fleet approaching Boulogne. Operation Moonshine involved a small flotilla of boats a few miles off the French coast, deploying radar-reflective balloons. They were linked to a device that amplified German radar pulses, making the flotilla appear on enemy radar screens as a large fleet. Loudspeakers on board the small craft broadcast the sound of ships dropping anchor to strengthen the deception.
Meanwhile, in Operation Titanic, forty aircraft dropped hundreds of dummy parachutists: 200 south-west of Caen and another 200 south-west of Dieppe. The dummies were cloth bags fitted to a cross-shaped wooden frame with an explosive charge that destroyed the dummies on landing, making it look as if the parachutists had burned their chutes and were now in hiding, ready to carry out ambushes or sabotage.
The aircraft also dropped rifle-fire simulators, bundles of Window and, alongside the dummy parachutists, two genuine SAS teams of paratroopers to reinforce the illusion that airborne landings were taking place. The SAS men had orders to carry out sabotage and take prisoners, but they were also instructed to allow some of their captives to escape, so that their reports to their German commanders would strengthen the impression of an invasion near Dieppe, rather than the true sites in Normandy.
While all
this was taking place, Operation Mandrel saw aircraft armed with radar jammers circling over the Channel between Littlehampton and Portland Bill, creating a jamming screen to hide the real invasion fleet from German radar, while specialised Lancasters and Flying Fortresses carried out radio-jamming and dropped a Window barrage over the Somme estuary to draw enemy night-fighters away from the vulnerable transport aircraft carrying airborne troops towards Normandy.
Operation Taxable and the other deceptions proved to be a huge success. Apart from the ‘convoy’ being fired on by shore batteries, intelligence intercepts showed that German commanders in the region had reported an approaching invasion fleet. The German forces had been fixed in place in the Pas de Calais and the destruction of the Seine bridges by British and American bombers later that morning left them trapped, unable to reinforce the embattled German defenders in Normandy. Well aware of the extraordinary efforts his squadron’s navigators had made to find a solution to an apparently intractable problem, Cheshire recommended several of them for decorations, but all were turned down with the terse comment, ‘This operation did not cross the enemy coasts, or at any time come under enemy gunfire. Consequently, it is not eligible to be considered for the award of decorations.’21
D-Day may have marked, in Churchill’s words, ‘the end of the beginning’, but there were still many perilous months ahead, and many further occasions where 617 Squadron would demonstrate their courage, and their sacrifice.
CHAPTER 7
The Fight Goes On
In the weeks following the invasion, Bomber Command’s efforts were primarily directed in support of the advancing Allies and the tempo of operations was ramped up by both day and night. During this period the command flew the same number of sorties in an average week – over 5,000 – as had been flown in the first nine months of the war. Between June and August over 180,000 tons of bombs were dropped, with only 30,000 targeted against Germany.1
On 9 June 1944, 617 Squadron was tasked with blocking the Saumur tunnel 125 miles south of the main battle area, on high ground above the river Loire, to stop a crack Panzer division that was being brought north by train to attack the Allied troops as they consolidated their Normandy bridgeheads. The raid, planned in great haste, would be the first operational use of a new 12,000-pound bomb developed by Barnes Wallis in conjunction with Vickers Armstrong.
Back in April, while the rest of the squadron had been bombing the railway marshalling yards at Juvisy, south of Paris, Nick Knilans’ crew, sworn to absolute secrecy, had been sent on a special duty to test a new weapon. Although the idea of 12,000-pound bombs was not new, the previous versions had been little more than three 4,000-pound ‘cookies’ bolted together. The new bomb, christened ‘Tallboy’, was custom-designed. Twenty-one feet long, it was torpedo-shaped and highly polished, with a slim, streamlined design that belied its 12,000-pound weight. It had a long tail of light alloy, four small square fins that were offset by 5 degrees to impart spin as the bomb dropped, greatly improving its accuracy, and a hardened, cast-steel nose to withstand the impact as it struck the ground and increase its penetration below the surface.
Dropped from an optimum height of 18,000 feet at an airspeed of around 170 miles an hour, a Tallboy would take 37 seconds to fall to earth. By the time it hit the target, it would be travelling at a terminal speed of about 1,100 feet per second – 750 miles per hour, roughly the speed of sound. Its slim profile, hardened nose and huge kinetic energy allowed it to drill down deep into the earth before exploding, causing a seismic underground ‘earthquake effect’ that meant a near-miss could be as devastating to a target as a direct hit.
A Tallboy 12,000-pound bomb falls earthward
Having loaded the Tallboy into a Lancaster that had been specially modified to carry it, Knilans’ crew flew over the bombing range at Ashley Walk in Hampshire and dropped the bomb from 20,000 feet. A camera had been placed right in the centre of the target to record the bomb in flight and the ensuing explosion. ‘The idea would have been a good one if Joe [the bomb-aimer] had been off target. He was bang-on again. The target became a crater, eight feet deep and a hundred feet across. The camera was never seen again.’
Wallis assured Sir Arthur ‘Bomber’ Harris that his new bombs could penetrate 15 feet of reinforced concrete. The Allies had no other weapon that could inflict such damage on the concrete blockhouses the Nazis were building to protect their new V-2 ‘terror weapons’, and only one squadron – 617 – could be relied on to drop them with sufficient accuracy from 18,000 feet, at which height a blockhouse would look no bigger than a pinhead.
The Tallboys had been delivered to Woodhall Spa in crates marked ‘kitchen boilers’ and were ‘hiding in the bomb dump’, so that even Leonard Cheshire did not discover ‘what these massive bombs were’ until shortly before the raid on the Saumur tunnel.2 When he eventually saw the new weapons, Les Munro remembers thinking, ‘Hello, this is going to be good!’
The squadron’s ground crews weren’t used to loading the new bombs, and they had to make rapid alterations to the bomb-bays of the Lancasters to house them,3 but loading them was still a complicated, time-consuming business. Three fuses had to be fitted into the rear of the nose section before the tail unit was bolted into place, and the bomb then had to be lifted by a six-ton crane onto a custom-built cradle on a trolley. The trolley was then towed by a tractor underneath the aircraft, and such was the bomb’s size and weight that, rather than winching it up into the aircraft’s bomb-bay, four armourers standing at each corner of the cradle had simultaneously to jack up the bomb into position. A metal band around the middle of the bomb secured it in place and arming wires were connected, allowing it to be fused in flight.
Three Mosquitos and twenty-five Lancasters of 617 Squadron took part in this first Tallboy raid. In pitch darkness, Cheshire flew in at 200 miles an hour, 50 feet above the ground, straight along the railway tracks towards the southern mouth of the tunnel. At the last moment he dropped his red spot fires, then pulled up in a steep climb and radioed to his men, ‘OK, A Force. Start bombing red flares. They’re right in the mouth of the tunnel.’
When the last Tallboy had been dropped by the first group, Cheshire flew back across the tunnel mouth to check the results of the bombing and then called in B Force to finish the job.
Mac Hamilton’s crew had been the eighth in line for take-off, but they were still trying to get the bomb adjusted on their aircraft when the others took off. An hour had passed by the time the problem was solved, but when Mac told his crew that it was too late for them to join the raid, his navigator said, ‘Not if we go straight there,’ because the others had flown a circuitous route to keep the air defences guessing about the bombers’ target for as long as possible.
Hamilton duly took off and was not far from the target when he heard Cheshire on the radio, calling in the last of the other aircraft to drop their bombs. Hamilton told Cheshire, ‘We’re ten minutes away. Do you want me to bomb?’
‘Yes, I’ll put down another marker for you,’ Cheshire said.
Hamilton’s crew dropped their bomb, and though it was difficult to spot the impact for the dust and smoke because ‘when these Tallboys go off, there is a terrific amount of smoke … we got very close.’4
Because the bombs penetrated so deep into the earth before detonating, none of the watching aircrews had seen more than pinpricks of light when their bombs exploded, but the eruptions of smoke, pulverised rock, chalk and earth that followed showed their devastating power. Three Tallboys hit the tracks and one penetrated the tunnel roof, drilling through 70 feet of earth and soft chalk rock into the tunnel itself, its detonation triggering a 10,000-ton rockfall that left a crater 25 metres wide at the surface and completely blocked the tunnel. The Panzer division was delayed for a crucial few days, allowing the Allied build-up of troops, tanks and equipment in Normandy to continue and the break-out from the beachheads to begin. So effectively had 617 Squadron done their job that the Saumur tunnel was not declared sa
fe and reopened until three years after the end of the war.
Although he continued to fly daylight ops, the Saumur raid proved to be Nick Knilans’ last night-combat flight. ‘It came at a good time,’ he said, ‘because my subconscious mind was beginning to rebel at the continued stress.’ Although he said he never had nightmares or even dreams about his wartime flying experiences, ‘occasionally my hands would feel like they were filled with writhing maggots’. Daylight flying was much less stressful because it was easy to see the horizon and keep from becoming disoriented, whereas night-time evasive actions – violent dives and turns – left his senses reeling, and his ‘dizzy feeling of falling out of control’ made him struggle to believe the dials on his instrument panel.
Knilans was beginning to display the clear signs of overexposure to incredibly stressful situations, but what is today termed ‘post traumatic stress disorder’ (PTSD) was barely recognised in the Second World War. Known as ‘shell-shock’ in the First World War, it was now described as ‘combat fatigue’. Psychiatrists believed that men in combat had a series of mental defences that were peeled away as the combat stress increased. The first defence was a belief in a distant ideal: ‘the war to end all wars’, ‘fighting for democracy’, etc. Nick Knilans had now lost his naive, youthful faith that the war would ‘unite everyone in America and end all discrimination’. When talking to other American servicemen, he learned that African-Americans were allowed to use the swimming pools at their base only on Mondays. On Monday nights the pools were drained and refilled with fresh water before the white American servicemen used them. The implications were obvious. Knilans also wrote to his parents in Wisconsin to ask if the sign reading ‘Gentiles Only’ at the local country club was still in place. It was.
