The take-off signal flashed in the darkness and the sound of aero-engines rose to a roar as the first three Ju 52s began to move across the airfield. They did so more sluggishly than usual, for each dragged a heavy burden—a second aircraft without engines: a glider!
As the tow-rope grew taut the latter jerked forward and jolted faster and faster down the runway. Then, as the towing craft left the ground, the glider pilot drew the stick carefully towards him, and the rumbling of his under- carriage grew suddenly silent. Seconds later the glider was sweeping noiselessly over hedges and fences and gaining height behind its Ju 52. The difficult towed take-off had been accomplished.
The time was 04.30 on May 10, 1940. From Cologne’s two airfields, Ostheim on the right bank of the Rhine, Butzweilerhof on the left, sections of three Ju 52s were taking off at thirty second intervals, each towing a glider. Becoming airborne, they steered for a point above the green belt to the south of the city, there to thread themselves to a string of lights that stretched towards Aachen. Within a few minutes forty-one Ju 52s and forty-one gliders were on their way.
The die had been cast for one of the most audacious enterprises in the annals of war : the assault on the Belgian frontier fortress of Eben Emael, and the three bridges to the north-west leading over the deep Albert Canal—the keypoints of the Belgian defence system to the east.
In each of the forty-one gliders a team of parachutists sat astride the central beam. According to their appointed task their number varied between eight and twelve, equipped with weapons and explosives. Every soldier knew exactly what his job was once the target was reached. They had been rehearsing the operation, initially with boxes of sand and models, since November 1939.
They belonged to “Assault Detachment Koch”. Ever since this unit had reached its training base at Hildesheim, it had been hermetically sealed off from the outside world. No leave or exeats had been granted, their mail was strictly censored, speech with members of other units forbidden.
Each soldier had signed a declaration : “I am aware that I shall risk sentence of death should I, by intent or carelessness, make known to another person by spoken word, text or illustration anything concerning the base at which I am serving.”
Two men were, in fact, sentenced to death for quite trifling lapses, and only reprieved after the operation had succeeded. Obviously its success, and there- by the lives of the paratroops, depended on the adversary having no inkling of its imminence. Secrecy was carried so far that while the men knew the details of each other’s roles by heart, they only discovered each other’s names when all was over.
Theory was succeeded by practical exercises by day, by night, and in every kind of weather. Around Christmas time the operation was rehearsed against the Czech fortified emplacements in the Altvater district of the Sudetenland.
“We developed a healthy respect for what lay ahead of us,” reported First-Lieutenant Rudolf Witzig, leader of the parachute sapper platoon which was due to take on the Eben Emael fortifications single-handed. “But after a while our confidence reached the stage where we, the attackers, believed our position outside on the breastworks safer than that of the defenders inside.”
Outside on the breastworks . . . but now did they propose to get that far?
The construction of the fortress, like that of the Albert Canal itself, dated from the early ‘thirties. Forming the northern bastion of the Lüttich (Liège) defences, it was situated just three miles south of Maastricht, in a salient hard by the Belgian-Dutch frontier. In that position it dominated the Canal, the strategic importance of which was plain: any aggressor advancing along the line Aachen-Maastricht-Brussels would have to cross it. The defence had made preparations so that all its bridges could be blown at a moment’s notice.
The fortifications themselves were embedded in a hilly plateau, and ex- tended for 900 yards north and south, 700 yards east and west. The individual emplacements were scattered, seemingly at random, over a five-cornered area (see plate following page 96). In fact, with their artillery casemates, armoured rotating cupolas carrying 75-mm and 120-mm guns, plus anti-aircraft, anti- tank and heavy machine-gun positions, they constituted a shrewdly planned defence system. The different sectors of the complex were connected by underground tunnels totalling nearly three miles in length.
The fortress seemed all but impregnable. On its long north-eastern flank was an almost sheer drop of 120 feet down to the Canal. The same applied to the north-west, with a similar drop to a canal cut. To the south it was protected artificially—by wide anti-tank ditches and a twenty-foot-high wall. On all sides it was additionally protected by concrete pillboxes let into the sides of the walls or cuttings, which bristled with searchlights, 60-mm anti- tank guns and heavy machine-guns. Any enemy attempt to get into the place seemed doomed to failure.
The Belgians had foreseen every possibility but one: that the enemy might drop out of the sky right amongst the casemates and gun turrets. Now this enemy was already on his way. By 04.35 all the forty-one Ju 52s were air- borne. Despite the darkness and the heavily laden gliders behind them there had not been a single hitch.
Captain Koch had divided his assault force into four detachments, as follows:
- “Granite” under First-Lieutenant Witzig, eighty-five men with small arms and two and a half tons of explosives embarked in eleven gliders. Target: Eben Emael fortifications. Mission: to put outer elements out of action and hold till relieved by Army Sapper Battalion 51.
- “Concrete” under Lieutenant Schacht. Ninety-six men and command staff embarked in eleven gliders. Target : high concrete bridge over Albert Canal at Vroenhoven. Mission: to prevent bridge being blown, form and secure bridgeheads pending arrival of army troops.
- “Steel” under First-Lieutenant Altmann. Ninety-two men embarked in nine gliders. Target: steel bridge of Veldwezelt, 3¾ miles NW of Eben Emael. Mission: as for “Concrete”.
- “Iron” under Lieutenant Schächter. Ninety men embarked in ten gliders. Target: bridge at Kanne. Mission : again as for “Concrete”.
Rendezvous was duly made between the two groups of aircraft, and all set course for the west, following the line of beacons. The first was a fire kindled at a crossroads near Efferen, the second a searchlight three miles further on at Frechen. As the aircraft approached one beacon, the next, and often the next but one, became visible ahead. Navigation, despite the dark night, was there- fore no problem at least as far as the pre-ordained unhitching point at Aachen. Yet for one aircraft—the one towing the last glider of the “Granite” detachment—things went wrong while still south of Cologne.
Just ahead and to starboard its pilot suddenly noticed the blue exhaust flames of another machine on a collision course. There was only one thing to do: push his Ju 52 into a dive. But he had, of course, a glider in tow! The latter’s pilot, Corporal Pilz, tried frantically to equalise the strain, but within seconds his cockpit was lashed as with a whip as the towing cable parted. As Pilz pulled out of the dive the sound of their mother aircraft died rapidly away and suddenly all was strangely silent.
The seven occupants then glided back to Cologne—one of them the very man who was supposed to lead the assault on the Eben Emael fortress, First- Lieutenant Witzig. Pilz just managed to clear the Rhine, then set the glider softly down in a meadow. What now?
Climbing out, Witzig at once ordered his men to convert the meadow into an airstrip by clearing all fences and other obstacles. “I will try to get hold of another towing plane,” he said.
Running to the nearest road he stopped a car and within twenty minutes was once again at Cologne-Ostheim airfield. But not a single Ju 52 was left. He had to get on the ‘phone and ask for one from Gutersloh. It would take time. Looking at his watch he saw it was 05.05. In twenty minutes his detachment was due to land on the fortress plateau. Meanwhile the Ju 52 squadrons, with their gliders behind them, droned westwards, climbing steadily. Every detail of their flight had been worked out in advance. The line of beacons to the German frontier at Aachen was forty-five miles long. By then the aircraft were scheduled to reach a height of 8,500 feet: a flight of thirty-one minutes, assuming the wind had been correctly estimated.
Squatting in their gliders, the men of detachment “Granite” had no idea that their leader had already dropped out of the procession. For the moment it was not all that important. Each section had its own special job to do, and each glider pilot knew at exactly which point of the elongated plateau he had to land: behind which emplacement, beside which gun turret, within a margin of ten to twenty yards.
It would moreover have been bad planning if the loss of individual gliders had not been provided for. As it was, each section leader’s orders included directions as to what additional tasks his team would have to perform in the event of neighbouring sections failing to land.
Nor was Witzig’s glider the only one to drop out. Some twenty minutes later that carrying No. 2 Section had just passed the beacon at Luchenberg when the Ju 52 in front waggled its wings. The glider pilot, Corporal Brendenbeck, thought he was “seeing things”, especially when the plane also blinked its position lights. It was the signal to unhitch! Seconds later the glider had done so—all thanks to a stupid misunderstanding. It was only half way to its target, and with an altitude of less than 5,000 feet there was no longer a hope of reaching the frontier.
The glider put down in a field near Düren. Springing out, its men requisitioned cars and in the first light of day sped towards the frontier, which the Army at this time was due to cross.
That left “Granite” with only nine gliders still flying. Sooner than expected the searchlight marking the end of the line of beacons came into view ahead. Situated on the Vetschauer Berg north-west of Aachen-Laurensberg, it also marked the point at which the gliders were to unhitch. After that they would reach the Maastricht salient in a glide, their approach unbetrayed by the noise of the towing aircraft’s engines.
But in fact they were ten minutes too early. The following wind had proved stronger than the Met. men had predicted, and for this reason they had also not reached the pre-ordained height of 8,500 feet, which would enable them to fly direct to their target at a gliding angle of one in twelve. Now they were some 1,500 feet too low. Lieutenant Schacht, leader of “Concrete” detachment, wrote in his operations report: “For some undisclosed reason the towing squadron brought us further on over Dutch territory. Only when we were some way between the frontier and Maastricht did we unhitch.”
Obviously the idea was to bring the gliders up to something like the de- creed altitude. But if this move contributed to the security of the force in one way, it certainly hazarded it in another. For now the droning of the Junkers engines alerted the Dutch and Belgian defence.
The time was shortly after 05.00 hours—nearly half an hour still before Hitler’s main offensive against the West was due to open. Though eight to ten minutes ahead of time, owing to the wind, the gliders needed, in fact, another twelve to fourteen to bring them over the target. At five minutes before zero hour these silent birds of prey were to swoop down amongst the pill- boxes of the Canal bridges and the fortress… before any other shot was fired. But now the element of surprise seemed to have been lost.
At last the gliders were set free, and the noise of their mother aircraft died away in the distance. But the Dutch flak was now on its toes, and opened fire on the gliders before they reached Maastricht. The little red balls came up like toys, amongst which the pilots dodged about in avoiding action, happy that they had sufficient height to do so. None was hit, but the long and care- fully guarded secret of their existence was now irrevocably exposed.
As long ago as 1932 the Rhön-Rossitten-Gesellschaft had constructed a wide wing-span glider designed for making meteorological measurements at high altitude. The following year, taken over by the newly established German Institute for Gliding Research (DFS) at Darmstadt-Griesheim, this flying observatory—known as “Obs”—was used for the first gliding courses under Peter Riedel, Will Hubert, and Heini Dittmar. It was tested for the first time in tow by Hanna Reitsch, later to become one of the world’s best known women pilots, behind a Ju 52.
Ernst Udet soon got wind of the project and went to inspect the “Obs” at Darmstadt. He at once recognised a possible military application. Could not large gliders like this be used for bringing up supplies to the front line, or in support of a unit that had become surrounded? Perhaps it could even operate as a kind of modern Trojan horse by landing soldiers unnoticed be- hind the enemy’s back.
Udet, in 1933, was still a civilian, and not yet a member of the new camouflaged Luftwaffe. ‘But he informed his comrade of World War I, Ritter von Greim, about the “Obs”, and shortly afterwards the Institute received a con- tract to build a military version. The prototype, under the designation DFS 230, duly emerged under the direction of engineer Hans Jacobs. The “assault glider” of World War II fame was thus already born.
Series production started in 1937 at the Gothaer vehicle factory. Its wings were high-set and braced, its box-shaped fuselage was of steel covered with canvas, and its undercarriage jettisonable: the landing was made on a stout central skid. This was another mark of Udet’s influence: as early as the twenties he had made some venturesome landings on Alpine glaciers with a ski- undercarriage.
The unladen weight of the assault glider was only 16 cwt, and nearly 18 cwt could be loaded—equivalent often men plus their weapons.
By autumn 1938 Major-General Student’s top-secret airborne force included a small glider-assault commando under Lieutenant Kiess. Tests had shown that such a method of surprise attack on a well-defended point had a better chance of success than parachute troops. In the latter case not only was surprise betrayed by the noise of the transport aircraft’s engines, but even if the troops jumped from the minimum height of three hundred feet they still swayed defenselessly in the air for fifteen seconds. Further, even the minimum time of seven seconds to get clear of the aircraft spread them out on the ground over a distance of about 300 yards. Precious minutes were then lost freeing themselves of their parachutes, reassembling, and finding their weapon containers.
With gliders, on the other hand, surprise was complete thanks to their uncannily silent approach. Well-trained pilots could put them down within twenty yards of any point. The men were out in no time through the broad hatch at the side, complete with weapons, and formed a compact combat group from the start. The only restrictions were that the landing had to await first light, and the area had to be known in advance.
It was this dictate of time that nearly caused the whole Albert Canal and Eben Emael operations to miscarry. For the Army supreme commander proposed to launch the opening attack of the western campaign at 03.00 hours, in darkness. Against this Koch argued that his detachment must make its own assault at least simultaneously with the main one, and preferably a few minutes earlier. And before dawn this was impossible.