The story of that particular idea is interesting.
by Rob_Boyter - 2/17/14 10:30 PM
In Reply to: Special ops by Willy
The problem was how to fly at precisely 60 feet above the water when all altimeters at the time ran off airpressure, which changes with the weather, and is imprecise at that height. Height was absolutely critical, as was speed. Scientists created the idea of two spotlights, one mounted in the nose one in the tail which were adjusted by geometry to come together to form a figure 8 to the side of the aircraft. The Flight Engineer (the Brits never used co-pilots) stuck his head into one of the blisters of the canopy to see how the lights came together, and simply talked the pilot to the right height. The actual bomb site was a plywood Y shape with pins on the upper arms and a peephole set on the bottom of the Y and the whole thing was hand held horizontally by the Bomb aimer. He looked through the peep hole and directed the pilot right or left until the pilot was flying precisely between two towers on the Mohne Dam. When the towers were perfectly aligned with the pins, he dropped the bomb a cylinder about 4 feet in diameter and 7 feet long which was spinning backwards and which because of that, bounced on the water. The idea was that the bomb would bounce over the Torpedo nets protecting the face of the dam on the water side, hit the face of the dam and because of the back spin would then crawl down the face of the dam until a hydrostatic fuse set off the explosive which was RDX. The bomb went off at 30 to 40 feet down, using the inelastic properties of water to abrupt movement like an explosion to direct most of the explosive force toward the dam face.
In the event, it took 7 bombs to breach the dam though one of those from the Aircraft flown by "Hoppy" Hopgood, struck the top of the dam wall and bounced over the dam and exploded fatally damaging the aircraft and killing the crew.
BBC tried to re-enact the raid using a twin engine plane with a similar arrangement to impart back spin to the bomb. They tried about 4 to 6 times, from 75 feet not 60, and couldn't do it. Their primary problem was finding a pilot who could do the dive to height precisely enough, find proper height and orientation to the towers on the dam.
?Of the 16? aircraft involved in the raid only 7 made it back to the base at Scampton. (the preceding has been done without reference to any book or on-line source and may be in error regarding number of aircraft but the rest is a cert.). Wing Commander Guy Gibson received a VC for the raid. Not a nice man at age 24. He judged people entirely based on accent and where they went to school. Public School (meaning Private School) fine. Grammar School, very doubtful, Regular open access schools, you were beneath contempt. He was very harsh with the "erks" or aircraftsmen who serviced the aircraft and kept them in perfect condition and even those who were flight engineers and gunners. Generally, in the RAF. the Navigator was an officer, the pilot a Flight Sergeant, and perhaps the Bomb Aimer and/or the Flight Engineer the same, which means that those absolutely critical men were not held in high esteem by "Gibbo". There could hardly have been a greater contrast between Gibson, and Leonard Cheshire.
The last wartime commander of 617 Squadron was ?Wing Cdr. Johnnie Farquharson RCAF who was a Civil Engineer from Toronto.
Standard joke was, "If you don't make it back, can I have your egg?" The crews were fed Bacon and Eggs after every mission. After the dams raid, some people got thirds.
A Lancaster or Halifax crew normally numbered 7. Both aircraft were not easy to escape from, and I think the Lanc was the worse of the two. 55,000 aircrew from the RAF and other British Empire squadrons did not survive the war. In the first 3 years of the war, more aircrew were killed than there were casualties from the bombing.
The RAF always maintained they could find the target at night. A survey which resulted in the famous, and highly funny sounding Butt Report named for an Oxbridge statistician who oversaw its production. determined that fewer than half the aircraft were getting within 5 miles of the target. Various electronic measures, particularly Gee and later an Air to Surface Radar set were able to help get them on target. Unfortunately H2S the radar set also could be homed in on by German Night Fighters. When the Brits adopted a "Watch my tail" radar receiver tuned to German frequencies, the Germans found that it leaked enough radio waves to enable them to locate and shoot down the bombers.
It was these statistics and problems that made the Mosquito such a stunningly effective bomber. They could fly as far as Berlin with a 4000 pound bomb load, exactly the same bomb load as the B-17 at that distance but at a speed in excess of 300 mph, and even if the radar directed radar equipped fighters onto them they were fast enough to get away 98% of the time. Wing Cdr Guy Gibson was killed flying the Mosquito. He flew into a hill in Holland, which gives you an idea of how low they flew generally, before anti-aircraft artillery could draw a bead on you, you were gone. Even radar guided AA had trouble keeping up. I believe the hill in Holland he hit was less than 300 ft above sea level.
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