The first Wallis-designed 'earthquake' bomb was the 12000lb (5 tonne) Tallboy. The Grand Slam was 22000 lb (nearly 10 tonnes) and I think its first major successes were the destruction of the Bielefelde viaduct and the Saumur railway tunnel (which stopped the Wehrmacht moving Panzer reinforcements by train to the Channel coast after D-Day).
There's a Grand Slam at Cosford Museum - it's big! The amazing thing is that if a crew couldn't locate the target they were ordered to return and land with the un-dropped Grand Slam still on board, because they were so expensive and time-consuming to produce. Not even the B29 Superfortress had the lifting capability to carry one.
I've got the Paul Brickhill book. It was the first published account of the Dams Raid, and in novel rather than documentary form, with imagined conversations between the characters (something I can't stand in a 'history' book). There are much better, more recent, books about the Dam Busters - a search on Amazon will locate them.
I was working for Foseco Ltd at Borken, not far from the Dutch border, a bit in the middle of nowhere. That was in the days when the Luftwaffe and other European air-forces flew the dodgy European-built F104 Lockheed Starfighter. The Germans I worked with had learned to recognise the sound of them approaching, and visibly flinched, as many Starfighters, being faulty, flew into the ground.......
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