Tomahawk

Originally posted by I luv Wight Originally posted by Jon Howes . With the wind free, after all the conventional foils have cavitated.... You do mean VENTILATED here yes?  since even moths don't do 40 kts??

For some reason cavitation and ventilation seem to get used interchangeably on this forum. If a foil actually cavitates there are probably going to be pits where the material has actually been eroded away!


Edited by m_liddell

Originally posted by Jon Howes Would this be the same Chris 249 who has been so "supportive" of the Monofoil work? Listen for the crackling of flames......

Yes, it's the same C 249.

I think I put up two posts about the Monofoiler on BDF, when it was (as it
still is) at model stage. The study of sailboat design development,
including the interplay of theory and practise, has been a major hobby of
mine for a long time, and I've asked one hell of a lot of innovators about
it.

The posts were musings about scale effects and
included my comment "Of course, I may well be talking rubbish...." and
"all I'm saying is that success in model form does not PROVE success in
full size form will follow." That doesn't seem like really wounding stuff.
And I still can't see what's so wrong with requesting proof of claims of
claims of ground-breaking advances before becoming a fan. I can't move
here for scientific publications and annuals and visiting academics, and
none of them get tetchy with being put to proof.

Having scanned through that thread, including your reply to someone
else of

If the question is "why has it not been done by someone else" (which is
what it looks like to me unless you explain otherwise) then this is the
argument of dickheads who do not understand invention. It needs no
further comment, get medical help.

and

The moth is a poor example. That class had not seen the kind of
engineering effort that world speed records had seen. It was guys mostly
building them in their garages.

It seems that there isn't any any use going further on this thread.In this
case, I asked a simple, factual query as you had requested in the BDF
thread (relate to a comment of yours about the importance of span, and a
comment from Jim Drake), and got a non-factual reply.









Edited by Chris 249

I think Chris 249 was entitled to defend himself there.

But I'm really looking forward to seeing how the production boat sails. I could believe anything from 'light/med airs dog' to 'unmissable sailing experience'. Bring it on. Still don't think it'll be meaningfully PY raceable, though, which would reduce its long-term appeal to me.

Note how quickly the unfoiled board catches up here:

http://www.youtube.com/watch?v=1oyWMusaDTI&feature=relat ed

 - not so much further off the wind, and i'm guessing the foiler doesn't have draggy ridges on it's low-pressure surfaces

Edited by Medway Maniac

Chris 249

"I think I put up two posts about the Monofoiler on BDF, when it was (as it
still is) at model stage. The study of sailboat design development,
including the interplay of theory and practise, has been a major hobby of
mine for a long time, and I've asked one hell of a lot of innovators about
it."

You did rather more than that, including implying the whole thing was a scam on the SA forum. Looking at many of your other posts on other topics you do have a certain "style". You REALLY don't like people having a go at developing anything you don't like, your logic being that you can't develop anything that you have not already done...... anyone spot the error here? Since your day is going so much more badly than mine I'll leave you to it.

"Listen for the crackling of
flames......"

Crackle crackle

In case anyone else is curious about wingspan and roll stability when foiling the board, span is settling out at 1 to 1.2 metres and rolling is only an issue when the foil is submerged since the water surface confers a little roll stiffness. As for the discontinuities causing drag, this only bites when not fully ventilated and submerged, when surface running the ventilation bubble encloses all the discontinuities. When waves are encountered the foil simply slices through the wave cap and takes the ventilation bubble with it. Linton reckoned that the foil was only on the water for about 25 to 50% of the time at speed, slicing waves does not bother it and this was a key aspect of its use on Monofoil. The famous foiling board video (nothing to do with me incidentally) where a normal board is burning past it shows a board on foils of tiny span, wingspan matters!

Jon.

Edited by Jon Howes

Jon, I cannot recall suggesting that the Monofoil was a scam; cannot see why that would have been claimed; and searches of BDF and SA show no such posts.

The BDF discussion between us was fairly civilised. I was genuinely interested in your Tomahawk foil as it seemed to be simple and had been subject to full scale tests.

Development is great. However, some of us may think that making claims of great future feats does not show a lot of respect for the state of the art and those who created it. I take your point (expressed on BDS) that you feel it's better to aim high.

Oh, and my apologies, the Moth quote was from someone else.

Mongrel, sorry if that's the way it seems to you; it's not the intention. Yes, I may be too tetchy when people criticise popular boats and I apologise for that.