Re: French sail-powered hydrofoil known as the ‘Hydroptère’
Hydroptere is basically just a brute force solution though.
I had a large slice of humble pie to eat when these guys hit their record, because when I saw their first craft I thought they didn't stand a prayer, but I spectacularly underestimated the level of committment and sustained effort the Sailrocket boys and girls were going to put into their project.
In many ways what these guys have done is roughly equivalent to breaking the sound barrier. For some time quite different sorts of high speed craft have been topping out around the 50knot region, because its about there you get into a phenomenum called cavitation where the blades that go in the water to control a craft create such low pressures around them that the water boils, and the things stop working.
The Sailrocket guys have genuinely got through the cavitation region and beyond, which hasn't been done before on an unpowered craft, and its a hell of an achievement. The most difficult engineering on this thing is not in the air, but in the water, and you can't praise them enough for achieving it.