Facing out wards foils on a lightweight tri.

Gee, Gary-it sure would be great to see some foiling pictures of your boats!
How about it? You know full foiling, not foil assist, ok? Looking forward to seeing them.......

 

Dont get too uppity Doug,

This from someone who's boat has foiled for maybe 5 seconds!! Yet claimed it a world first. Lets see your boat fully foil not foil assist.

Tony

 

Doug's laughably erratic pond toy mentally self-inflated to full size hallucinations?

 

I've looked at the posted pics of the IMOCA, and as Gary says, they seem to be pointing outwards when in use, just like the scow ones, and only upwards when the boat is docked.

I do not understand the reason for the change of subject now, I was expecting a nice pic of a leeward big V foil on a sailing monohull, providing both: upward force, thus righting moment; and windward force to resist leeway.

 

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Sure Tony, glad to oblige:

 

Gary, show us just ONE picture of any boat of yours foiling-I'd really like to see it. I bet its a lot better than my poor "pond toy". And one more:

 

Yeah but its OK to say your boat has foiled but then there has been foiling boats since WW2 if not before.

Doug to stand any sort of credence on those forums, go out and sail it tell it breaks and then tell us all about it, until then you are just another modeller with ideas.

 

Sure, Wayne, sure. I'd just like to see any picture at all of Gary's "real" boat or boats flying clear of the water like my "pond toy" does-just one..... Here is a skiff-probably an R Class sailing with two outward pointing foils-retracting the windward foil:

 

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Sorry Wayne but that is a silly comment. The Fire Arrow uses a foiling system never, ever used on a trimaran in the past-not in the whole history of the earth! And you and Gary knock model testing in a profoundly uninformed way: RC models have been used for decades to test foiling and foil concepts by people like Dr. Sam Bradfield, Hugh Welbourn, Paul Larsen, Yves Parlier, Greg Ketterman, Matt Burns(CBTF) and more.
Attempting to ridicule my boat as a "pond toy" is just ignorant and woefully uninformed!

 

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See post #5. And this thread: http://www.boatdesign.net/forums/sailboats/quant-23-foiler-scow-53468-3.html
Though on the Q23 leeway prevention is done mainly with the keel fin.

 

Doug, these guys then take their models and create full size models, models are just a tool to approximate and generalise a theory, its just a tiny part of the process, yes your model has seen the light of day and sailed, now you have to get down to the real task and build a full size version to confirm your theory.

At this stage you have just a theory confirmed by a model, which has very limited time spent in actual testing and at ths point has not really convinced your peers around you I'm afraid to say.

 

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Again, you pontificate on where an RC model comes in the design process with absolutely no idea how it really works. I worked with Dr. Bradfield one summer when he used an RC trimaran platform I designed and built to test the foil system of the 40' SKAT he was about to build. His testing was about 4 days a week on the water for three months-a major commitment of time and effort.(Which is exactly what I'd do in a heartbeat if I could!)
RC models, with a comprehensive testing program, can completely vindicate(or not) a foil system, altitude control , configuration, foil area, rig placement and many other details. I was there and I know what went into his testing and my testing has been similarly comprehensive and is not complete yet. But we do know that the unique foil configuration works in light air at relatively low speed-a central goal of this project. We know the ama placement, foil placement, rig placement, platform dihedral, two stage ama all work as intended.We know the balance of the boat is nearly perfect.
We know the foil positions, wand length, foil area, flap area, rudder foil area and AOI of all three(4) foils is correct for the conditions the boat was tested in.
All of this stuff scales up very well with highly accurate results and makes this kind of testing a time saver and money saver in the long run. The results are not a part of a "generalized" theory-they are concrete results of specific testing that can lead to directly building the fullsized version based on what has been(and will be) learned. It allows the fullsize boat to be way ahead of the development game compared to a boat where model testing has not been done.
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I want to see any one of Gary's boats foil because he has made it part of his lifes work to attempt to ridicule my test model(and model testing in general). He has claimed the boats are foilers-I'd just like to see a still picture of ONE boat flying above the water on foils. I think Gary's designs are absolutely gorgeous-just beautiful. And I bet they would look great flying!
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Pictures: L=Flyer3 platform designed and built by me modified for foils utilizing the same system that eventually was used on Skat by Dr. Sam and his team, R= the 40' SKAT foiler with foils, foil configuration and altitude control developed during model testing:

 

This is veering way off from the original thread content but ... It is true I haven't posted any high speed images of my boats foiling/flying ... because I sail my boats solo (mostly) - but they do sail very fast in moderate and fresh winds - and that is when I'm too busy steering/trimming to dig out camera. Not that I give a rat's flatulence about what sedentary boffins think about my boats.
However here is a shot on Sid in 3 to 4 knots wind speed (this is the only time I can think of taking photographs); check out the foil and main hull wakes and figure the speed - then imagine the performance in 10-12knots wind. I have to reef on Sid above that figure. And then the boat becomes a brute in terms of speed with its very rapid steering.
Figure it out Doug; an extremely light platform (230kgs) and high aspect ratio rig - and take it from me, the boat is very, very fast.

 

Outward pointing foils on a small tri

I've thought a lot more about this and I think outward pointing foils like those used on the Q23 could really work well on a small trimaran allowing a narrower platform beam and great RM under way- as long as the foil does not generate lateral resistance for the boat when flying.
A problem may be flying the main hull in light air because of the distance of the boat CG from the center of lift of the lee foil. This problem can be dealt with allowing the boat to foil in very light air as well as be very fast in strong wind.
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Part of the concept on the Q23 is low foil loading* which leads to fairly big foils-about 6' from the side of the boat on the 23 and say, for an 18' tri around 4.7' from the side of the lee ama. The cool thing about the application of these foils is that the trimaran platform can be kept street legal w/o folding from about 18-20' down to say 12' LOA. The foils would be easily retractable.

* Substantially under Moth mainfoil loading around 171lb/sq.ft.@80% for a Moth(one 175lb crew) main foil vs around (rough estimate) 124lb/sq.ft.@80% for the Q23(with two 175lb crew). Which explains why the Q23- even with a ballast keel- was able to foil earlier than an A Cat foiler or Moth in very light air.

 

The IMOCA boards are made so that the root is supposed to lift up and to leeward, and the tip is lifting up and to windward (look at the cambers). So there is no pressure reversal along the span.
Ketterman was probably not referring to the toppled J's but to the standing J's as found on the picture in that post... It's not so much about which way they are oriented as it is which way they lift. I would love to see the flow visualized - wouldn't there be a powerful vortex if the lift reversal was abrupt? My intuition is that a outward J has worse induced drag than if you separated it into a daggerboard and a hydrofoil? (whereas an inward J is the opposite - less induced drag than the dagger/foil separated)

Could we make a Moebius foil to get any more confused maybe?