This guy has beaten the world speed record by 15 knots!!!! Is that not like someone coming out and beating Usain Bolt over 100 meters by 30 meters???? Am I looking at this too simplistically or is this achievement that incredible???

and here is the video of this great run:

We can read that this thing was "designed for 65kn"... now that they are peaking at 68kn, all of this footage is showing where/how it can by tweaked...

In particular:
- there is *a lot* of spray coming off the pods + foil... a little draggy?
- the span+wing is flying a bit high.
- from the footage there looks to be some control issues... and we know that "control is good".

Some time ago I posted that I couldn't see how VSR1 would be a record contender (aka +50kn)... this thing is not just "an evolution" of that design, it is significantly different in too many ways. I wouldn't be surprised that VSR2+mods could achieve +70kn (actually probably would have to be a VSR3, as geometries change).


And further, I am really keen to read about the pitting seen on the foils. Cavitation bubbles get larger with increased speed... and 70kn (130kph) is starting to push well into that area.

At one point I hypothesized the shape for a super-cavitating foil. Since then there appears to have been a free'ing up of that knowledge. For example, we now understand how penguins can jump onto an ice-shelf:

www.gizmodo.co.uk/2012/04/penguins-rocket-through-the-water-aboard-supercavitating-bubble-jets/

I am now thinking a shape based on something like this, might work for windsurfing:

www.amc.edu.au/news/research/cloud-cavitation-0

mathew said...
We can read that this thing was "designed for 65kn"... now that they are peaking at 68kn, all of this footage is showing where/how it can by tweaked...

In particular:
- there is *a lot* of spray coming off the pods + foil... a little draggy?
- the span+wing is flying a bit high.
- from the footage there looks to be some control issues... and we know that "control is good".

Some time ago I posted that I couldn't see how VSR1 would be a record contender (aka +50kn)... this thing is not just "an evolution" of that design, it is significantly different in too many ways. I wouldn't be surprised that VSR2+mods could achieve +70kn (actually probably would have to be a VSR3, as geometries change).


And further, I am really keen to read about the pitting seen on the foils. Cavitation bubbles get larger with increased speed... and 70kn (130kph) is starting to push well into that area.

At one point I hypothesized the shape for a super-cavitating foil. Since then there appears to have been a free'ing up of that knowledge. For example, we now understand how penguins can jump onto an ice-shelf:

www.gizmodo.co.uk/2012/04/penguins-rocket-through-the-water-aboard-supercavitating-bubble-jets/

I am now thinking a shape based on something like this, might work for windsurfing:

www.amc.edu.au/news/research/cloud-cavitation-0

Interesting reading Matt, I always wondered how the "boiling" could do so much damage...

"The damage is caused by microjets formed as the bubbles collapse when they reach regions of higher pressure. The violent collaspse of these small bubbles occurs in very short, nanosecond, timescales creating pressures of thousands of atmospheres, and temperatures of thousands of Kelvin."

So we(windsurfers) layup fins with fine airlines feeding pressurised gas to strategic points on the fin. A gas cannister or aerosol feeding the fin manifold is activated with a boom mounted "Nitro" button. - I'm on it

slowboat said...

If you didnt know, Paul is from Perth, and also windsurfs...

paul is from healesville in victoria. i used to sail catamarans with him in vic. one of the nicest and most positive blokes i've ever met