New High Performance Monofoilers

[Tcubed]

Steele, i do not understand your statement as i have difficulty imagining a monohull sailboat which retains its bilateral symmetry wrt fluid flow when heeled.

Originally Posted by Tcubed

Steele, i do not understand your statement as i have difficulty imagining a monohull sailboat which retains its bilateral symmetry wrt fluid flow when heeled.

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Not only that: is it a "High Performance Monofoiler"?

[sigurd]

probably more so than any of the others in this thread - the ones so far has had at least 4 water foils each

Originally Posted by sigurd

probably more so than any of the others in this thread - the ones so far has had at least 4 water foils each

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Water foils? Hmmm....The most important thing about every boat featured so far on this thread is that they use bi-foil technology on monohulls. That is,they have just two lifting hydrofoils. That is the point of the thread,more or less......

[sigurd]

four foils in the water... except the one with Howes' foils on it... It's almost just got three, in one of the pics. but you are right as well. nice thread btw

Thanks and thanks for your participation!

From the rclass site: ( www.rclass.org )
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What's an R Class Skiff?
Extreme performance, light weight, skiff style, development dinghy class in the truest sense(see the rules for details).

Length 3.9m (max) 12.79'

Hull no minimum weight (typically 29-35kg( 63.8-77lb ) painted), 1.4m (4.59') minimum width

Construction Unrestricted (typically ultra lightweight Carbon/Foam)

Rig Unrestricted - typically two spreader pre-bent carbon spar

Working Sails Area is restricted 13m2( 139.9sq.ft.)- construction and rig plan are unrestricted - ie. wings, pocket luff, rotating masts are all acceptable

Kite 20m(65.6 ft.) circumference resulting in a 30-36m2 (322.8-387 sq.ft. ) surface area


Crew 2 (minimum)

[Cheesy]

Originally Posted by Doug Lord

From the rclass site: ( www.rclass.org )
----------------
What's an R Class Skiff?
Extreme performance, light weight, skiff style, development dinghy class in the truest sense(see the rules for details).

Length 3.9m (max) 12.79'

Hull no minimum weight (typically 29-35kg( 63.8-77lb ) painted), 1.4m (4.59') minimum width

Construction Unrestricted (typically ultra lightweight Carbon/Foam)

Rig Unrestricted - typically two spreader pre-bent carbon spar

Working Sails Area is restricted 13m2( 139.9sq.ft.)- construction and rig plan are unrestricted - ie. wings, pocket luff, rotating masts are all acceptable

Kite 20m(65.6 ft.) circumference resulting in a 30-36m2 (322.8-387 sq.ft. ) surface area


Crew 2 (minimum)

Isnt this the boat that you predicted wouldnt foil very well in light winds and would need more sail area?

Originally Posted by Cheesy

Isnt this the boat that you predicted wouldnt foil very well in light winds and would need more sail area?

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Yes, if it was to have the same takeoff profile as a Moth does in very light air.
A good indicator of that is W/SA with W weight in pounds and SA sail area in sq.ft.
Moth,Mirabaud, RS600FF 2.558 or less
R Class Foiler approx. 3.13
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But in the area where this boat is sailed it's almost always windy enough that this really doesn't matter. It would matter in areas where you wanted to foil in the lightest wind or if you were racing a two person foiler that had a W/SA like the other boats....

[Cheesy]

I know exactly where it sails. Interestingly, some of the future developments of this class go right against a lot of your ideas.....

Originally Posted by Cheesy

I know exactly where it sails. Interestingly, some of the future developments of this class go right against a lot of your ideas.....

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Why don't you enlighten us all about how ANY of their ideas go "against" any idea of mine?

[Cheesy]

because they are not my ideas/solutions

Oh, I see....
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Great R Class article: http://www.rclass.org/seasons/2008/f...carbon-cook-up

This little tidbit was picked up on Luca Damics site ,posted March 9, 2009:
"Another interesting thing was talking to Julian Bethweite at Woolahra about the foiling 49er last Sunday. I have seen the powerboat prototype and the final configuration (at this stage) is a centreboard hydrofoil (no flaps) with a forward canard foil which will also act as a rudder sporting a small flap controlled by a wand. No rudder at back."
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This configuration has been tried many times and has yet to work successfully-but this IS Julian Bethwaite....

http://www.luka-damic.com/

Anybody interested in this subject should read the paper by Bill Beaver presented at the 19th Chesapeke Sailing Yacht Symposium. Though the paper is specifically about the Moth much can be learned that is applicable to
other bi-foilers. Here is a quote from the Summary and Conclusions section of the paper:
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"--Aerodynamic drag plays nearly as great a role in upwind speed as hydrodynamic drag. Reductions in aerodynamic drag through smaller hulls, cut away tramps, faired tubing , etc. could well be meaningful.
--Higher is better. The hydrodynamic drag on the foils decreases with reduced immersion. Increased foil wave drag is not significant. The feedback control systems to hold altitude have improved markedly in the last year or two, allowing sailors to fly higher with less risk of crashing. Further efforts spent to reduce foil immersion will improve performance.**
--Existing rudder lifting foils appear too large. Experiments wth smaller foils may yet lead to improved performance."
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**I'm 100% convinced that a major improvement in racing performance can be
made with the adoption of a manual altitude control system with simultaneous
mainfoil/rudder foil control and easily adjustable mixing. The disadvantage is that it wil require much practice for it to become second nature-the advantage is that it will be slightly faster.
Also, on boats designed for it a manual system facillitates intentional jumping-just for the fun of it....