How the Dambusters Trained to Drop the Specially Modified Bomb

History Hit Podcast with Jonny Johnson

4 mins

26 Nov 2018

This article is an edited transcript of “Johnny” Johnson: The Last British Dambuster on Dan Snow’s History Hit, first broadcast 22 November 2015. You can listen to the full episode below or to the full podcast for free on Acast.

I think we were getting more fun out of the actual flying to think about worrying what was happening, and what the target was. We knew it was a special target, we’d been told that.

We’d also been told there had to be complete security about what we’re doing and we told no one about the type of training that we’re doing. But that training was interesting because it was at such a low height.

The prescribed height was a hundred feet. Very few people flew at a hundred feet, and we tended to be even lower than that.

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There were occasions when early aircraft came back with a few tree branches stuck in the wings.

In Lincolnshire, there’s a town called Suttonbridge, and as you fly out from the south, there are electric cables also cross the bridge. Now this practice wasn’t briefed, but everybody did it just for the hell of it. We flew under the cables and up over the bridge.

Great thrill that was, a wonderful time. I learned that one of the residents here, he had an aunt living in Suttonbridge at that time. He said the people in Suttonbridge were scared stiff about all these low flying aircraft.

Training to drop the bomb

We didn’t drop the bouncing bomb in training. We didn’t even spin it. But we started off with limited means of navigation.

The navigator in the bomber had a map with the track mapped out and the navigator would indicate what I should be seeing. If I saw it, that was fine.

Front view of a scale model of the Möhne Dam photographed in 1954. The model was constructed in 1941 at the Garston Building Research Station. Built to facilitate the testing of underwater explosive devices, it was 1/50th scale of the actual target. Credit: Imperial War Museums / Commons.

If I didn’t, I picked out something else equally prominent and he could adjust his courses, if necessary, on the fly.

The bombers had to make their own bomb site, and it consisted of a triangle of plywood with a peg in each angle.

But the distance between the base pins had to be specific and the distance from the base, the apex, had to be equally specific.

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On the bombing range, they arranged two poles specific distances apart, and the practice was that the bomber held a single pin to his eye, while directing the pilot until the two base pins were in line with the two poles and dropped the bomb, practice bombs, I hasten to add.

If you got it right first time, great.

If you didn’t, you did it again and again and again until you got it right, until we got to the stage where I think most of us were fairly accurate with our bombing.

We also used some of the dams in this country for bombing practice.

Most notably, Derwent water in Derbyshire. This had towers, so we could use those for sighting. It also had a marker in the reservoir which showed where the bombs should drop.

You used the same approach as you had on the range, and if your bomb dropped close to that marker, that was fine.

Movie still, showing an inert, practice version of the Upkeep bouncing bomb being dropped during a training flight by members of RAF 617 Squadron at Reculver bombing range, Kent. The bomb’s designer, Barnes Wallis, and others watch the practice bomb strike the shoreline. Credit: Imperial War Museums / Commons.

We had no idea what the target was. We didn’t think. Too young to worry about anything.

At that stage I was 20, 21. But at this stage, when we first joined the squadron, one of the things that struck me was the experience of the crews.

Most of them had done one tour, some were on their second tour.

The next thing was the aircraft, stress on the aircraft. The Lancaster was modified to have no mid-upper turret.

It seemed as though the bomb doors were sealed and these two legs standing down on either side of the fuselage in the front, just below the nose, just behind the nose. What the hell was that for?

Then the bomb arrived. It was just like a glorified big dustbin. But at least it indicated to us what those legs are for.

A German official stands next to an unexploded, British Upkeep bouncing bomb. The weapon was recovered from the wreckage of Avro Lancaster ED927/G ‘AJ-E’, piloted by Flt Lt Barlow. The aircraft crashed at 2350 hours on 16 May 1943 after striking power lines 5km east of Rees, Germany. All on board were killed. Credit: Imperial War Museums / Commons.

They obviously are going to carry that bomb when it was loaded onto the aircraft. But that was as far as we got with it.

We went through their training with these cross country bombing practices.

Night-time training

Then we went to do a twilight situation where the front Perspex of the cabin and nose were covered in blue sheeting.

The pilot and the bomb aimer wore night vision glasses, which created a twilight situation. What I never understood was how you were supposed to map read over the North Sea. One of the turning points was over the North Sea.

Wing Commander Guy Gibson (in door of aircraft) and his crew board their Avro Lancaster bomber for No. 617 Squadron’s raid on the Ruhr Dams, 16 May 1943. Credit: Imperial War Museums / Commons.

However, you had to hope like hell you crossed the right point, the right bit of coast, at the right place and you hit the right place as it came back on dead reckoning.

From there it was onto bright moonlight night flying.

It had to be bright moonlight for it to get to the stage where Gibson thought it was worth it to go.

We still had no idea what the target was. Gibson did. He’d been told by then.

Header image credit: A practice 10.000 lbs ‘Upkeep’ weapon attached to the bomb bay of Wing Commander Guy Gibson’s Avro Type 464 (Provisioning) Lancaster, ED932/G ‘AJ-G’, at Manston, Kent, while conducting dropping trials off Reculver. Credit: National Archives / Commons.