The Dam Busters Read Online Free Page B

explosion tamped by water a tiny plug of a few ounces of gelignite blasted a satisfying hole through a concrete wall 6 inches thick. From that he calculated he would need only 6,000 Ib. of RDX to breach the Moehne Dam. With his new idea he could cut the case weight down to a little over 3,000 Ib., making the complete bomb about 9,500 Ib. Less than 5 tons. The new four-engined Lancasters would carry that to the Ruhr without trouble.

CHAPTER III THE GREEN LIGHT

    ARMED with sums and theories, Wallis faced the task of convincing officials in their brick and stone lairs along Whitehall and other influential thoroughfares that he could put his bomb in the exact spot. He called on Professor Patrick Blackett, director of an “operational research” branch, and Blackett, a spare, rather intense man, listened to his ideas, carefully examined the calculations, riffled them back into a neat pile and said quietly:
    “We’ve been looking for this for two years.”
    Wallis was electrified.
    “I’d like you to leave these with me for a while,” Blackett said. “There are one or two people I know who would be interested.”
    Blackett moved fast. As soon as Wallis had left he went to see Sir Henry Tizard and told him what he had heard. Tizard also moved with unorthodox haste, driving down to Weybridge next morning, where Wallis eagerly explained it all again.
    “It seems,” Tizard said when he had finished, “that the main thing to establish is whether this freak of yours will really work, and if so how we go about putting it into practice.”
    At Teddington, he said, was a huge ship-testing tank which would be ideal for experiments. He also thought there should be more tests to check how much explosive would theoretically punch a hole in a dam.
    “I think I know just the thing,” said Wallis, whose “damology” researches had been fanatical. “There’s a small disused dam in Radnorshire; no earthly use any more as a dam and won’t ever be. We could try and knock it down.”
    “Who owns it?” Tizard asked.
    “Birmingham Corporation.” Wallis knew all the answers.
    “We’ll try them,” Tizard said, and Birmingham Corporation, with a little prodding, said yes.
    It was a nice little dam, about 150 feet long and quite thick, curving gracefully across the mouth of a reach of Rhayader Lake, high in the Welsh hills west of Leominster. The corporation had built a bigger dam across the mouth of the lake to feed a little river that tumbled out of the hills.
    Wallis estimated that the old dam would have a fifth of the resistance of the Moehne, an ideal test model. He calculated the smallest charge that should knock it down and set off with a packet of RDX and some explosives engineers. Wrapped against the raw mountain wind, he wasted little time, measured out the charge, tamped it in a sealed casing and lowered it deep into the water against the dam wall. Behind the rocks, his mouth dry with anxiety, he pressed the plunger and the lulls echoed with sound. Water spurted a hundred feet high, the lake whipped into fury, and as the water plunged back into the void, the concrete crumbled and a hissing flood burst into the main lake. Wallis, pink with glee, saw there was a ragged hole in the dam 15 feet across and about 12 feet deep.
    For the next five months he experimented whenever he could in the tank at Teddington, an enormous thing well over a hundred feet long. He wanted to find out exactly how to control a skipping missile, so that after a given number of bounces over a given distance he could make it reach a certain given point at a certain minimum speed and height. At this ultimate spot the missile would have to be either slithering across the water or only just a fraction above it. He had to find out the best shape to use and the best combination of weight of missile, and height, speed and power of release. And what a headache it was, too. He had a spring-loaded catapult so that he could measure the force behind it, and