Dolphin Address 17
June 23th 2006
Some of you may have been pondering the cliff hanger I left in the last edition. When you try to explain something that has developed over years of trial and error experiments you tend to leap by insight where the novice needs to proceed by tiptoe. Therefore I thought to better split up my approach in palatable steps, so time will be on your side to sink it down.
Last year at Schiphol instead of paying 325 euro for half a night's sleep in some posh Sherrything hotel I chose to wake through the night, by a coke here and a sandwich there and a lot of slomo trotting and window shopping. My eyes caught a foam spat model of a plane toy that was advertised to fly underwater by its buoyancy. I bought it for Dusty and me to play with.
Back on the meadow I watched the autumn Gannets dive or rather rocketeer into the water for fish. I was impressed by the power of their flight, wondered how deep they went and if they could somehow 'fly' under water.
Wings, like on airplanes, have a heaving capacity when they come into motion. The air going over the wing covers more distance than that on the underside. Therefore it is thinner and this creates an upward suction called 'lift effect'. Quite a few properties of air motion are similar to that in water, though by its density are much more concentrated. I figured for to obtain a lift effect in water, dimensions and angles needed to be less articulate. This idea I had already addressed by changing the stiff wooden flaps of the wing into flexible rubber sheets. The idea behind this was that they would bulge by the scoops, differentiating the water travel lengths and creating a lift effect natural to the up- and down leads. It was an improvement, but not as effective as I had hoped for.
Photo: Willem Verhulst
The toy plane and the gannets reanimated my interest in the lift effect and the split second insight it generated led to a major improvement, but not like I expected. It hit me that if I would disconnect the leading edge from its trailing rubber sheets I could bend the cutting profile into an angle that might enhance the lift effect. I'm pretty sure this actually does work, but it is very hard to separate optimism from detailed fact. But also another effect became apparent. Because I can bend the leading edge into the tilt without forcing the flaps counter wise the counter water the wing steers in much easier, simultaneously scooping rather more water backwards. So I figured I could handle a larger wing with the same effort.
The making of a wing takes three weeks. Because the first one worked so well, making the larger one was a major challenge. I tried it out in a crowded swimming pool in Drachten, Holland. It worked miraculously well, but was slightly harder to manoeuvre through the crowd. I have not yet tried it out with Dusty. Could have, but it's a 'waiting for my moment' kind of thing. You will have to hold your breath on this one.
Willem has supported my courage and photo/video-graphed my boat adventure. I'll burn it on a CD, send it by mail to my smarter e-sister Carola and she'll put the footage in the video department, together with some rock runs and a whole lot of great capture of the dolphin. Stay tuned, I hope to have them up in a week.
Jan Ploeg, Meadow Fanore, June 23rd 2006
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