The Dam Busters Read Online Free

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.
    Thirty thousand pounds was nearly 14 tons. That was the explosive alone. Add the weight of the thick case of special steel—another 40,000 odd Ib. It meant a bomb weighing 70,000 Ib.—over 30 tons, and the Victory Bomber, still only on paper and straining the limits of feasible aircraft construction, would carry only a 10-tonner.
    The next meeting of the Air Attack on Dams Committee was in a fortnight and it required little thought to foresee it would be the last meeting.
    Wallis would not give up.
    Supposing, he thought, a bomb could be exploded under water against the dam wall. The shock wave punch would be much greater. So the explosive needed would be smaller. So would the bomb casing.
    But how to get a big bomb in the exact spot—deep enough for the shock punch and pressed against the wall to make the most of it? Or, as it might require more than one bomb, how could you get them all in the exact spot? A torpedo? But the dams had heavy torpedo netting in front of them, and so torpedoes were out. You could drop a bomb from very low level for accuracy, but bombs don’t simply “drop “. Just after release they carry a lot of forward speed, giving them almost a horizontal trajectory for a while. If you dropped a bomb— even a whopper—from very low to get the accuracy it would simply skid off the water ; so that was no good. If you dropped it high enough to enter the water cleanly, you only had about one chance in a thousand of putting it right in the exact spot.
    Wallis probed at this problem for days and every time he probed he came slap up against the same old problem—the only way would be to drop something from very, very low and somehow make it stay where it was supposed to. But that seemed to be impossible. He remembered his last holiday with the youngsters just before the war began when they had been skipping stones across the smooth water of a little pon,d. How on earth, he thought, could one toss a stone low like that and stop it skipping. Drop any shape of bomb very low at a couple of hundred miles an hour and heaven knows where it would skip to. When dams are full there is practically no space between the level of the water and the top of the dam wall and in his wry imagination he visualised a series of grotesque bombs hurdling over the dam wall and flying harmlessly downstream. What a pity, he thought idly, that