Hinged Bruce Foil Proa

...... as we all know > a corner is stone age technology
so make a curve there !
first of all .....

and any opinion on sections > have to have a basis in experience !

like have you been ever thinking on what kind of edge we need ?
that this edge will have to be asymetric for this 2 way section !
because the pressure side is always the pressure side
and the flow has to make it around to the other side on any shock loading
so this need is the first priority



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Just an idea that might make foil section selection less problematic

 

Your foil profile looks good and it seems to be similar to the profile of "loonys" foil which proofed to be successful in all situations when being tested. The foil showed a lot of power so that it was impossible to lift it out of the water and to capsize the proa. Even the small float would not leave the water.







Date is not correct.

 

Timothy, your picture looks quite interesting. Can you give a comment, please ?

 

Timothy, the problem with this set up is that as the ama lifts, the foil gradually looses hold whereas, the hinged system keeps full hold to a good heeling degree and the sail as a chance of spilling the wind before capsizing.
Manfred, having seen Loonys profile, you posted, I can say his foil is more efficient than the one I sketched out.
Proagenesis, the section for this foil will always be a compromise. Loonys has chosen the one I suggested above, the parabola. As for being a 'stone age' profile because of sharp angles, yes it is lesser efficient but by far easier to build at a very minimum loss of performance. I can live with it.

 

What follows was not easy for me to write, and I wrote this with a heavy heart. I know this note will 'hurt some feelings.' But, here goes.

Your foil will experience catastrophic loss of negative lift during certain conditions and speeds, and you cannot tell me when those conditions will happen, or why those conditions would exist. Yet, you want me to make it better for you?

WOW.

I can do that. It is really easy, but, the more I thought about that, the more I realized, I do not want to be involved with trying to put a band-aid on your 'invention,' when you need a redesign.

Your approach is, IMHO, dangerous.

Sadly, you have used fancy words and some will believe you know what you are doing.

I am leaving this conversation.

Wayne

 

..... well ... shure > the piver tris had corners too > on their hull
but we are at the third generation here >
not the first ....

this going as well for the back development of loony
who got the idee from us > years ago

but un fortunatly not going forward !

just take a look at http://www.proatech.org >> triproa >
and take a look at the date up loaded > 2001

this was at the time more advanced > as all the things shown today
here by others ....

you can as well look at videos at > http://www.proatech.org
and real boats from 1995 at http://www.proadesign.com

further more > a proa is not an advantage over a cat >
until the loa is over 30' .... not some 20'

and with models you can try things
you never would take the risk for in a maned >

so loonys project is a no no .... all the way !
for real testing we have been using a 10' rc model
you can see some at >> http://www.proatech.org wave.gif

we will up load some pictures of this ..... at a later time .....


regards the team of proagenesis


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...... sorry about that !

but if you can not have a scientific discussion about .......
then it will shurely be better for all !


after years of testing >
with the right hinge > meaning the right angle of attack !
see http://blog.proadesign.com

we have come to the conclusion
that a hvf will hold in any thing but a methane gas bubble
coming up from the ocean floor .....


and if this will happen >
and the bubble is not large enough to sink the whole boat
any boat !

the hvfp will just shoot up to the wind
because the lateral center will be going drastically forward >

so not much will be happening .....

for further information about this > see as well >
http://www.studiobunker.de/vector_foil_proa_test4.htm
another member of the proagenesis team >

and just go to the right upper corner and click there ..... for more !


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Oh, please, Wayne, do not leave this conversation. We need you to share your knowledge with us.

Most of us know the problems of a hinged foil. Robert Biegler who has written the most and best (for me) about hinged foils ( for instance: http://www.ayrs.org/Catalyst_N23_Jan_2006.pdf) points out, that a simple plastic bag, a floating fishing net, seaweed or a floating log can ruin the water flow around the foil, a sudden gust and wave action can destroy the grip of the foil causing a capsize. I did the math for a floating log and a 15m Foilproa sailing with 20kns and found out, that the foil would be smashed with nearly 2000kg before the proa will swing around. We are no illusionists.

But I think it is useful to get more info about the hinged foil proa. Nobody can do alone such a development work.

 

I'm still puzzling over the benefits of this hinge foil. Is it really an advantage? Flying the ama is a desirable property. With the ama liping from top of wave to top of wave, gives a smooth, comfortable and fast run. This hinge foil would prevent it, forcing the ama to follow all the ripples and life aboard would turn into hell plus, would be a hell of a wet sailing, with all the sprays this foil is lifting. Am I wrong?

 

well ... just see any of the test videos > it is heaven on earth ......

http://www.proatech.org

and even a vfp is better then any traditional proa
I have tried this for years in up to bft 10 !

and waves as high as the boat was wide .....

 

..... you are an illusionist > thinking you can defame a heavenly solution
seen by the fostering of your back ward development

of my development .....

no plastic bag will do any thing > not even a big one .... period !
because the hvfp will at most > just shoot up into the wind ....
if the fin should ever even come out ......

no fishing net can do more then stop you >
as much as it would any dagger board !

I have been sailing around mar menor in spain for months
with all those nets there .....

no log in your way will do as much damage > as on a dagger board !
because not all the weight of the whole boat is behind
so .... it will just stop the fin and the boat can go on .....

robert biegler > sorry to say > has no idee about any thing >

or he would not have send me the same flyer years ago >
you have been having this courageous idea .... to showing around > here too ......

with the only result
of me having to avert my eyes from such a insult to any inteligence !
because of the concept being in principle .... not functional .....


ps .... I am still waiting for any valid .... real arguments here ............
from people going an to a new concept with an clear mind !

backed by an actual experience ...... with the vector fin concept ....
in a real environment > meaning waves and gusts
not a bft 4-6 and no swell it all !

because in such a situation > we need no hvf > but any vf will do !
http://www.proagenesis.org


regards the team of proagenesis


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..... not only .... will the straight fin lose its hold
but it will > as soon as it will be coming out though a swell >>>

force itself ever more out !
this being the problem with all straight fins !

only a curved fin will not add to this coming out
and if having a radius smaller as the hinge is away
it will be self adjusting .....


regards proagenesis


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at ...... http://hvfp.proadesign.com/

you can see the index of the ..... hinged vector fin building notes
the pictures ..... are not there yet >

since the whole thing was originally posted at the yahoo group > proadesign

if you cant wait to have me add the pictures ..... in the future >
you can go to the yahoo group > itself >

http://groups.yahoo.com/group/proadesign/?yguid=289126699
but you need to be a member to get to see the files !


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if you are interested in an extensive buildung manual for the vfp ....
as opposed to the short 10 steps included in the vfp plan ....

you can contact >>> wanda elliot > don elliots widow > at >>> rite2wanda@yahoo.com
for the vfp25 building manual in pdf ......