Latest book reviews: Dam Busters: owners' Workshop Manual, Haynes 2011.
At the core of this story is Barnes Wallis, an aircraft engineer working for Vickers-Armstrong. He had been on the team, which produced the efficient geodetic structures of aircraft like the Wellington bomber. In his spare time he began to work on ideas for weapons to shorten the war. Much of German industry depended on the water and hydro-electricity produced by the dams in the Ruhr area. Destroying them would significantly cripple the war effort. In addition, the flooding which would result would cause devastation over an important part of German industry.
It wouldn't be easy, in an age before rocket propulsion; explosives were delivered by gravity and the speed of the bomber dropping them. Tests on model dams and a real redundant one in Wales, showed that an underwater explosive charge very close to the dam would have the desired effect. The problem was how to get it there. Wallis had the idea for a backward spinning cylinder, which would skip over any protective booms, nestle against the dam wall and roll down until it reached the right depth. The same bomb could be used against ships in harbour, skipping up to a ship's side and rolling down under the ship to blow it up. He even envisaged a forward spinning version, which could roll across the ground until it reached a canal or defensive wall.
His record in aircraft design gave him the credibility to allow testing of model dams and spinning bombs. After a lot of ups and downs, the results were good enough to order modifications to some Lancaster bombers and the formation of a special precision bombing squadron, 617. Components were scavenged from other weapon systems. The motor for spinning the bombs was used on submarines. The fuse to trigger the bombs was from a depth charge. The resulting bomb, known as 'Upkeep', was so big it could not be wheeled under the Lancaster nose to reach the bomb bay. A crane had to lift the tail high enough to get the bomb in from the back.
The book details the solutions to the challenges of flying at the right height, using spotlights on the plane, and releasing the bombs at the right distance, sighting on features on the dam, to let the bomb do what it was designed to do. The photographs of the results show how well it was achieved. The resulting devastation significantly disrupted German industry and had affected morale on both sides at a key time in the war.
Having built a special operations squadron, Wallis then put forward a series of other proposals for weapons they could deliver. These ranged from the 12,000 lb Blockbuster, a giant blast bomb with a thin skin, designed to flatten a large area simply by creating a huge shock wave; through to the Tallboy series and the 10 ton Grand Slam bombs designed, with a heavy cast shell, to penetrate deep in the ground and create an earthquake effect. The huge bombs required yet more modifications to the Lancasters to carry them.
These latter penetration bombs produced an underground void into which the surrounding area collapsed, bringing down any adjacent structures. Dropped from 40,000ft, they hit the ground at speeds around Mach 3. They were used against a variety of targets including: a railway tunnel at Rilly-la-Montagne used to store V1s, the battleship Tirpitz in a Norwegian fjord, and the U-boat submarine pens at Brest. The submarine pens were protected by a concrete roof some 5 1/2m thick. Tallboys created craters some 2m deep and 8 1/2m wide on the top and the shock wave produced an even larger hole on the underside of the roof, filling the docks below with rubble. The book has many photographs from reconnaissance missions and German sources showing how effective they were. The problems of dropping bombs from such heights with the required accuracy, in an age before computers as we know them, are covered in some detail
The book is full of technical explanations rather than being the story of an engineer, who designed extraordinary weapons, and the brave crews, who risked their lives to deliver them to their targets, after all it is an 'owners' manual'. However the human story shines through to give a feeling for the desperate times that required such ingenuity and sacrifice.
As ever, Haynes has immaculate timing. Peter Jackson, of Lordof' the Rings fame, is due to re-make the Dam Busters film this year.
* Title Dam Busters--Owners' Workshop Manual 143 onwards (all marks and models)
* Author lain Murray
* Publisher Haynes
* Publication date 2011
* Reviewer Colin Ledsome MEng CEng FIMechE FIED MCMI FBIS MDS
* ISBN 978 0 85733 015 4
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|Article Type:||Book review|
|Date:||Jan 1, 2012|
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