Dambusting, R/C Style

Disclaimer: no dams were actually busted in the making of the video below. But that doesn’t mean that a scale-model homage to the WWII Dam Busters and their “Bouncing Bombs” isn’t worth doing, of course.

In a war filled with hacks, [Barnes Wallis]’ Bouncing Bomb concept might just be the hackiest. In the video below, [Tom Stanton] explains that [Wallis] came up with the idea of skipping a bomb across the surface of a lake to destroy enemy infrastructure after skipping marbles across the water. Using barrel-shaped bombs, he built a rig that could give them the proper amount of backspin and release them at just the right time, letting them skip across the surface of the lake while the bomber made an escape. Upon hitting the rim of the dam, the bomb would sink to explode near the base, maximizing damage.

[Tom]’s scale rig ended up being a clever design with spring-loaded arms to release a 3D-printed barrel after being spun up by a brushless motor. He teamed up with R/C builder [James Whomsley], who came up with a wonderful foam-board Lancaster bomber, just like RAF No. 617 Squadron used. With a calm day and smooth water on the lake they chose for testing, the R/C Lanc made a few test runs before releasing the first barrel bomb. The first run was a bit too steep, causing the bomb to just dive into the water without skipping. Technical problems and a crash landing foiled the second run, but the third run was perfect – the bomb skipped thrice while the plane banked gracefully away. [Tom] also tried a heavy-lift quadcopter run with the bomb rig, something [Barnes Wallis] couldn’t even have dreamed of back in the day.

Hats off to [Tom] and [James] for collaborating on this and getting the skipping to work. It reminds us a bit of the engineered approach to rock-skipping, though with less deadly intentions.

23 thoughts on “Dambusting, R/C Style

  1. Bah. Don’t let the prop failure put you off. It isn’t typical. Crashes? Bah! Glue is fine till there is so much it makes the plane heavy.

    Today’s electric models make the R/C hobby a lot easier than it was back in the glow and diesel fuel engine days. It’s a very worthwhile hobby with quite enough tech to it for any hacker to enjoy.

  2. Historical tidbit: Germany started emplacing nets and subsurface barriers ahead of dams to protect against airstrikes in WWII. Skipping bombs on the surface was the idea developed to counter the countermeasures.

    1. They also couldn’t send in slow aircraft like Fairey Swordfish to drop right behind the torpedo nets, because the torpedoes in use then needed a certain distance to get themselves running at the right depth and arm themselves.

      1. “the torpedoes in use then needed a certain distance to get themselves running at the right depth and arm themselves.” Didn’t the Japanese overcome that problem at Pearl Harbour?

      1. Oh BTW, @HaD Mods, isn’t it annoying to constantly check on mistakenly reported comments, just because the “Report comment” button is placed on the right side?

        For the sake of a consistent web-page design, you should at least move the “Post Comment” button to the left side (and maybe add a “Report self” button to the right :)

        1. Since I’m right handed I will scroll up and down the comments with my right thumb.
          I’ve lost track of how many times I’ve “clicked” “Report comment” for no reason at all with no way to reverse the action. There are so many logical ways to provide that functionality, and then there is the way the HaD site handles it.

  3. I once talked with a military photographer who worked with the original project. Originally a tail-gunner, he was made a Sgt. and later a photographer. They needed footage of the spinning drum in its mount from below as the plane was flying at various test speeds with various test configurations. Flying over a vehicle with a cameraman on it wouldn’t provide steady enough footage. They dug a fairly deep long trench with a reasonably flat bottom, then placed long trays the width of the trench at the bottom in a continuous line. They added mercury to each tray, adjusting the amount of mercury in each until the surface of the mercury was on the same level plane in all trays. With the depth of the trench, its sides kept stray light out, except from ‘straight above’. They mounted the camera on the plane, aimed down, and flew the plane over the trench, getting the view of the drum and its mount reflected back to the camera by the flat level surface of mercury. (I guess Health & Safety took a few weeks off…)

  4. I was interesting to see the water spray up from the dropped drum and almost hit the back of the RC plane. This was apparently an issue with the low level drop and in some of the earlier test, the water spray was enough to cause damage to the back of the plane.

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