VECTOR FOIL
hello ...... here are a few of mike stolles videos of his hvfp model 4 test
http://www.youtube.com/watch?v=HU0rdLkBaZc
http://www.youtube.com/watch?v=50o2AKkmAUs
I can not even imagine .....
what other sail boat principal could survive such an under taking .......
As food for thought, in case you haven’t come across it yet, here is the link to my earlier work on this type of thing:
All those moving parts do make me a bit uncomfortable, but it’s a very interesting design… I’m wondering a bit though, how do you prevent weather helm on a reaching course with that design? Obviously you can design the whole thing to be neutral on for example a close-hauled course, but how it maintains its functionality on different courses, is not entirely clear to me.—Does reaching involve rotating the entire aka assembly, thus bringing the center of effort closer to the centerline, as the angle you are sailing relative to the wind increases? That would counter what would otherwise be a problematic increase in yawing moment to windward…
What prevents the vector foil, which is mounted to the ama, from leaving the water? Using lots of weight to keep the ama in the water doesn’t sound that great, because you’d be making a bit more of an atlantic proa out of it, increasing drag and weather helm… You can’t have everything though. 😊
Thanks for the links to the videos Fritz, I just got around to having a look at them. Quite nice, and quite impressive to see that model fighting its way through the surf. From what I could tell, it seemed like the hinged foil really did quite a good job of staying the water, with the exception of the wave which hit the boat directly on the beam at around 0:29 in the first video, but all in all, quite impressive.
Do you know if they’ve done any tests of that model without the hinged foil, with just a corresponding weight on the ama to replace it? It would be nice to see a direct comparison, with and without the hinged foil just to get a feel for how much of the heeling moment is actually being countered by the foil.
Thanks for the links to the videos Fritz, I just got around to having a look at them. Quite nice, and quite impressive to see that model fighting its way through the surf. From what I could tell, it seemed like the hinged foil really did quite a good job of staying the water, with the exception of the wave which hit the boat directly on the beam at around 0:29 in the first video, but all in all, quite impressive.
....... for any one having not seen my own tests >
they are at http://www.proatech.org ..... for a comparison .......
Do you know if they’ve done any tests of that model without the hinged foil, with just a corresponding weight on the ama to replace it? It would be nice to see a direct comparison, with and without the hinged foil just to get a feel for how much of the heeling moment is actually being countered by the foil.
...... I will have to admit ..... being behind all of his doings ......
we have been ..... working ..... together for many years .......
http://www.studiobunker.de/vector_foil_proa_test1_engl.htm
http://www.studiobunker.de/vector_foil_proa_test2_engl.htm
http://www.studiobunker.de/vector_foil_proa_test3.htm
http://www.studiobunker.de/vector_foil_proa_test4.htm
he has done some other test on about the same location from the pier >
but the camera did get wet > so there is no record of this .....
As food for thought, in case you haven’t come across it yet, here is the link to my earlier work on this type of thing:
All those moving parts do make me a bit uncomfortable, but it’s a very interesting design… I’m wondering a bit though, how do you prevent weather helm on a reaching course with that design? Obviously you can design the whole thing to be neutral on for example a close-hauled course, but how it maintains its functionality on different courses, is not entirely clear to me.—Does reaching involve rotating the entire aka assembly, thus bringing the center of effort closer to the centerline, as the angle you are sailing relative to the wind increases? That would counter what would otherwise be a problematic increase in yawing moment to windward…
What prevents the vector foil, which is mounted to the ama, from leaving the water? Using lots of weight to keep the ama in the water doesn’t sound that great, because you’d be making a bit more of an atlantic proa out of it, increasing drag and weather helm… You can’t have everything though. 😊
Most of the Vortex proa models had a pantographing ama arrangement. The sail thrust vector could be aligned with the CLR on most headings (close hauled to broad reach). Model 4 didn’t have any rudders and relied entirely on adjusting the aka angle and the rake of the sail for steering. It sounds awkward but I actually found it to be a positive and responsive steering method.
These models were all attempts at neutral heeling moment rigs, so the vector fin is not required to produce a downforce to balance heeling. The only reason for using a vector fin was to be able to fly the ama at a constant height above the water surface.