The Dam Busters (2 page)

“Such earth movements,” said a learned paper, “are capable of doing much damage at great distances.”

It looked as though Wallis had found his answer. Or part of it.

CHAPTER II —AND REJECTED

HE worked out theoretical effects, more pages of figures, and decided there was a chance that a 10-ton bomb exploding deep in water by a dam wall would punch out a hole a hundred feet across.

Supposing the bomb did not go as deeply into the earth as the figures predicted? Wallis worked out the effects of a 10-tonner exploding about 40 feet deep. In theory it would throw out the staggering amount of 12,000 tons of earth, leaving a crater 70 feet deep, with lips 250 feet across. He worked out the circumference of the crater and from that the maximum number of men and machines that could gather round the edges. Working day and night they could not fill it in under fourteen days ! Supposing one such bomb was dropped accurately in a marshalling yard! Or on a vital railway or canal or road where ground contours prohibited a detour!

Wallis did not get too excited. No bomber in the world would carry a 10-ton bomb. Or for that matter even a 5-ton bomb far enough to get it to a target.

Back to pencil and paper. He knew the limitations of aircraft design in 1940 and in a couple of weeks he knew it was possible to build a 50-ton bomber to carry a 10-ton bomb 4,000 miles at 320 m.p.h. and a height of 45,000 feet. He drew up rough specifications and christened it the “Victory Bomber.”

And the aiming of bombs—notoriously hit and miss, mostly miss. Wallis found that increasing height did not greatly increase the problems and estimated that new bomb sights being developed and special training could put the bombs near enough to a target to destroy it.

That was the beauty of this 10-ton bomb. It should not have to be a direct hit! The earthquake shock would be so great that a near miss should shake a target to destruction. And another thing—a big bomb exploding 130 feet deep would not crater the surface but cause a huge subterranean cavern. Put such a bomb alongside a bridge or viaduct, and if the shock wave did not shake it to pieces the cavern underneath would knock its support away. An opening trapdoor—a hangman’s drop ! The bridge would collapse into it.

There was one other possibility in it—perhaps the greatest of all. A few such bombs, accurately aimed, might shatter the roots of a nation’s war effort. That could mean the end of the dreadful “Guernica” carpet bombing, which saturated an area with bombs so limited in effect that the area had to be saturated to make their use militarily worth while. Wiping out cities and civilians at the same time!

Wallis spent weeks setting it all out on paper and took it to people he knew in the R.A.F. and the Ministry of Aircraft Production. It was Dunkirk time. A potent new weapon had never been better timed.

Wallis’s paper on the “earthquake bomb” roused three main emotions in officials: (1) Lukewarm interest. (2) Incomprehension. (3) Tactful derision.

One man understood and did what he could: Arthur Tedder, a quiet, intensely likeable man smoking a pipe, chained to a desk in Whitehall. But he was only an air vice-marshal then and did not have the influence he acquired later. He brought the bomb and Victory Bomber to the attention of several people in high places but the only result seemed to be a ubiquitous manifestation of courteous but implacable inactivity. Every machine in the country was working overtime on other vital things and the ambitious and excellent four-engined bomber project was just getting under way. It was a fair assumption that it might be disastrous to dislocate that in favour of the Victory Bomber, which would inevitably take much longer to develop. That automatically prejudiced the shock-wave bomb, because there was therefore no aircraft in sight which could drop it from Wallis’s prescribed height of 40,000 feet. The new bombers would probably not be able to lift it or, if they could, to carry it far enough to drop it from higher than 20,000 feet, which was not likely to be enough.

And then on July 19, out of the blue, Wallis got an urgent summons to see Lord Beaverbrook, the bright-eyed firecracker who was Minister for Aircraft Production. With “The Beaver” interested anything could happen, and probably at speed. He caught the first: train to London, cooled his heels a few minutes in an ante-room and then the big door opened and a young man said:

“Lord Beaverbrook will see you now, sir.”

Wallis jumped up, cuddling his calculations under his arm, and crossed the threshold, nervous with anticipation; and there was the little man with the wide, mobile mouth, sitting slightly hunched in his chair. It was the speed with which things happened that shook Wallis as much as the things themselves. No gracious, measured preliminaries. He was still in the middle of the floor, walking, when the little man barked:

“What’s this about a ten-ton bomb?”

Wallis told him as concisely as he could; difficult for a scientist, who always feels compelled to go into technicalities, but he kept it short and lucid and Beaverbrook was interested.

“You know how short we are of stuff,” he said. “This thing’s only a theory. We’d have to stop work on other vital things to make it and then it might be a flop.”

“It won’t be that,” Wallis said stubbornly.

“We’d still have to stop work on other things.”

“It will be worth it.”

“Take too long, wouldn’t it?” said “The Beaver.” “A ten-ton bomb and a bomber twice the size of anything else sounds like something in the distant future.”

“We can do it in stages, sir,” Wallis said. “I’ve got drawings for two-ton and six-ton bombs on the same principle. My Wellingtons can carry the two-tonner all right. The new four-engined ones can carry the six-tonner. They’ll be operating in a year.”

“Well, I’ll see my experts about it,” Beaverbrook said. “If it’s going to mean diverting too much effort I don’t like your chances.”

Little seemed to happen for a while but behind the scenes things were moving in a ponderous government way. Little snippets filtered through to Wallis, particularly from that astute ally, Arthur Tedder. Nothing much; just that So-and-so had consented to look into the idea and that So-and-so had expressed mild interest. Wallis thought the prospects were still favourable. Sir Charles Craven, managing director of Vickers, was sympathetic and felt confident enough on November I to write to Beaverbrook suggesting he give permission to go ahead on both 10-ton bomb and Victory Bomber.

Then Tedder was posted to take over the R.A.F. in the Middle East and Wallis had lost his keenest supporter in the sacred and essential precincts of Whitehall. It was soon after that Craven sent for him.

“I’m afraid I haven’t very encouraging news for you,” Craven said as kindly as he could. “Air Council seem too wary of big bombs. They still believe stick bombing is necessary.”

“But can’t they
see
what a really big bomb would do?” Wallis said pleadingly.

“Apparently not. They say that from experience they would rather drop four 250-pound bombs than a thousand-pounder. Much less a 22,000-pounder.”

“Could they understand my calculations, sir?”

Craven did not comment on their understanding. He said diplomatically that he doubted whether the members would have the
time
to go individually through all the calculations. Which was probably true. And then gently: “They say that anyone who thinks of ten-ton bombs is mad.”

Wallis went back to Weybridge in anger, but in the morning the anger had mostly gone and in its place was outraged stubbornness. He started writing a treatise on his 10-ton bomb and called it “A note on a method of attacking the Axis Powers,” the kind of obscure title so favoured by scientists; the word “note” being particularly misleading, as such things are often as long as a book.

Wallis’s was. He started by outlining his theory of crippling an enemy by destroying the sources of energy, and went on to discuss in exhaustive detail the physical qualities of the targets, shock waves, blast, penetration, bomb design, aircraft design, charge/weight ratios, aiming problems, possible effects, repair potentialities, backed up with pages of graphs and formulae and equations. It was a
tour de force,
explaining step by step so lucidly that a layman could follow it if he took the mathematics for granted.

The “note” took Wallis several months, and then he had it roneoed and bound and posted copies to seventy influential men in science, politics and the services.

Results were not long coming. A secret service man called on him with a copy of the “note” under his arm.

“Did you send this to Mr.–—?” he asked.

“Yes,” Wallis said. “Why?”

“I’m afraid you shouldn’t have done so, Mr. Wallis.”

“Why?”

“It’s very secret stuff. This sort of thing must be handled very carefully and only reach authorised persons. Mr.–— was very surprised when this arrived in the post. We were concerned too. I quite realise you didn’t mean to be…”

“I sent out seventy of them,” Wallis said calmly, and the Secret Service was appalled.

“Seventy!” he said. “
Seventy!
Who? To whom? But you shouldn’t have. This is vital and very secret ! “

“Is it? “said Wallis mildly. “When I showed it to the authorised persons they said I was mad. I’m supposed to be a crackpot and this is regarded by authorised persons as fiddle-faddle.”

The secret service man said, “Oh ! “He asked for the names of the seventy. Wallis read them out and the secret service man, who seemed a little uncertain of his ground, went back to London to investigate further.

He appeared again a couple of days later.

“Well, it’s all right,” he said, “this time. We’ve decided that as so many were sent out so openly it’s actually rather a good form of security. No one will dream it’s all so secret. But please don’t do it again.”

Wallis bowed gravely. “I hope it will not be necessary again,” he said and the incident was closed.

A few days later there was another result. A copy had reached a Group Captain Winterbotham, who had an office in the City and was used to dealing with unorthodox aspects of the war. He had found it convincing, called on Wallis, and Wallis explained more fully. Winterbotham caught some of his enthusiasm. He knew Sir Henry Tizard, who was scientific adviser to the Ministry of Aircraft Production, and drew his special attention to Wallis’s paper.

Tizard read it carefully; as a scientist he could follow the intricate calculations. He went down to see Wallis at Wey-bridge and was impressed.

“I’d better form a committee to study this more fully,” he said. “It would have to have pretty solid backing from expert opinion. You’ll understand, I know. It would divert effort from other important things if we were to go ahead with it and we’ve got to be reasonably sure it would be worth while.”

“Of course,” Wallis said. He felt like singing.

Not long after, Wallis met the committee. At the head was Dr. Pye, Director of Scientific Research at the Ministry of Supply, and the others were scientists too. Wallis explained his ideas and described the probable effect on Germany’s war industries if the dams were breached. There was only one really worthwhile time of the year to breach them, and that was in May, when the storage lakes were full after the winter thaw and spring rains, and before the sluice gates were opened to water the country and canals for summer. Then you would get the greatest floods, the most serious loss of water and power. Dr. Pye said the committee would be a few days considering.

A week later Wallis faced the committee to hear theirfind-ings. His worst fears were soon over; the report was fa vour-able, but, as they read on, a little disappointingly so. They thought that the dams showed possibilities and the upshot was another committee. This one focused the aim more definitely; it was to be called “The Air Attack on Dams Committee.”

The members were again scientists and engineers and in a mood to be interested in something new because even German bombs, though they were more efficient than R.A.F. bombs and killed thousands of civilians, had demonstrated the limitations of small bombs.

“With this big bomb,” Wallis earnestly impressed on them, “you don’t have to get a direct hit. I think a ten-ton bomb dropped fifty feet away stands a good chance of knocking a hole in a dam like the Moehne. A near miss like that ought to be simple enough to organise.”

One of the members, Dr. Glanville, of the Road Research Laboratories at Harmondsworth, suggested building a model dam and testing the theories with scaled-down charges of explosive. Wallis accepted delightedly.

Over the next few months, whenever he could spare time from his arduous work at Vickers, Wallis helped Glanville design and painstakingly build a model dam one-fiftieth the size of the Moehne with tiny cubes of concrete, scale models of the huge masonry blocks in the real dam. The model was about 30 feet long, 33 inches high and up to 2 feet thick, a low wall arched between earthern banks, secluded from prying outside eyes in a walled garden.

They flooded the ground at one side to simulate the lake, and Wallis exploded a few ounces of gelignite under the surface 4 feet from the model to give the effect of a 10-tonner going off 200 feet away. There was a commotion on the water and a couple of patches of concrete flaked and chipped.

“Not so good there,” Wallis said. “Let’s try it closer.”

He exploded more gelignite 3 feet from the dam, and there was a little more damage. He set off another charge 2 feet away and still found only minor chipping.

At a distance of 12 inches (representing a 10-tonner 50 feet from the dam) the gelignite caused a couple of cracks in the outer structure; but they were small cracks, not enough to harm the dam significantly. They tried several more charges but the cumulative effect was not encouraging.

Months had passed since the first hopeful meeting of the committee, and Wallis could see that their early co-operation was freezing. Glanville built another model, and Wallis tried bigger charges to see what
would
smash the models at a distance. One day a few extra ounces of gelignite a foot away sent a mushroom of water spraying over the wall round the garden and as the spume cleared they saw the water of the little lake gushing through the burst dam. Slabs of concrete had cracked and spilled out and there was the breach that Wallis had been wanting. He calculated the scaled-up charge which, dropped 50 feet away, would smash such a hole in the Moehne. The answer was something like 30,000 Ib. of the new explosive RDX, and the gentle scientist did not need pencil and paper to estimate the significance.