Prototype V8 F 8.0A
Rigged on CC mast 490 100% (GA Sails C100 490 ENIR) ... normally not so away from 490 NP mast bend curve
Static overview :
The sail needs more downhaul tension than other foil sails like Hyperglide, IRIS X or GoldFoil ... probably due to the more important mast bent curve.
Both upper cambers don't touch the mast, but we can't add spacers. The bottom one has a lot of pressure.
There are some wrinkles in the luff pocket ad the panel upper boom
The volume of the sail is important in the bottom to the 3rd batten. There is a cut in the volume on the 4th batten, where the sail is pretty flat.
The center of volume of the sail is more centred than with other foil sails (like phantom, Xo, severn) ... where top draft is more forward.
The upper cam lips are appying presssure in the monofilm part of the luff pocket, and damage it : the camber is too large regarding the diameter of the mast. One should use a more narrow camber ... and add some spacer so that the camber can have some pressure on the mast, and gives some volume near thge leading edge of the sail at this position.
The downhaul pulley sould be more inside the sail so that the sail could be lower on the deck.
On the starboard side, the cams lock correclty. On port side, they are not locked : the sail stay in between .. .even when helping with hands. One sould try by removing botton cam. Things are worth with only 28cm of extension
On the water
The sail is pretty light and dynamic. In 5-7 knt of wind, the puming is not enough to fly. In fact, the sail is not so powerfull, eve, when pumping. During the pumping movement, we don't feel the pressure on the wind ... I imagine that it is due to too few volume in the head profile.
The things are better in starboard side than port side. When going upwind on port side, the panel upper the boom is vibrating
When flying, the sails is stable and light. In that case, the power is easy to handle, and there is low back hand pressure ... just enought to go upwind easily.
Next tests :
- using a NP Mast (still waiting from Bastien)
- removig bottom cam
- adding spacers to 3rd and 4th cambers
Prototype V8 F 6.0A
Rigged on X9 430 (Reglass 10 years old version)
The correct setting is with 26cm extension
When tensionning the sail, the outhaul tension is medium when the leach is closed. It become pretty strong when beginning to open the leach. The head of the sail, and especiallly the top end pannel is widely openned, when the rest of the sail is not. The leach openning is not regular, rather we have on some other sails, and on the 8m. The idea on the 6m (for medium wind) is to have a more opened leach than on 8m
About the luff pocket, and cams, we have the same configuration than with the 8m2. The mast panel and luff pocket is very constrained (a lot of tensions). The draft of the sail is pretty far from mast, and the leading edge is very flat. Cambers don't lock on one side : they stay in between starboard and port side ... especially if outhall tension is a bit low.
With 4 cams, the lower camber is very constrained and never lock. Upper camber don't touch the mast, and the most high camber is too large considering mast diameter and luff pocket width.
When removing the lower cam, things are not better : the rotation of the sail is easier, but the cams 2 and 3 never lock completely. When not in wind, we have the batten curve on one side, and the cams on the other side
When you push the draft on the other side, the cams are rotating the other way
I didn't found a setting so that cambers touch the mast everywhere (not possible to put spacers on that type of camber), and gives more leadgin edge thickness
On the water
This first test occurred in high wind (gusty 15-25knt). the sails is very easy when sailing upwind. The penetration in the air is efficient, and the sail is very stable (absolutely no back end pressure, even in strong gusts). The sail is not powerfull.
During jibes, the sail is very light in the hands
The global stiffness of the sail is pretty high ... pumping seams to be a bit strong is this small size
When releasing boom tension, the leading edge remain very thin, and the draft is still far backward
When sailing on starboard side, the colored panel upper boom is vibrating when going upwind
Tests to do : using an up to date TPX mast, rigging with less outhall tension, sailing is less strong wind, and see what's about pumping on the 6m2, removing upper camber which is no use since it don't touch the mast.
New test of 8.0 with more wind (10-15 knt)
This time, I have tied to remove the lower camber.
The rigging is the same, not possible to have a clean leading edge with 'normal' downhaul tension ... even if there is less pressues on the lower part of the sail
On the water, the sail is still dynamic and light in the hands, but the backend pressure became pretty strong ih 13-15knt gusts ... largely more than our Phantom IRIS X of Xo Gold Foil reference sails (used the same day in the same conditions)
Then i tried to release downhaul tension so that the leading edge to be cleaner. It needs 2-3cm less so that we would have no more the double curvature on the leading edage batten
In that situation, cambers are locking correctly on one side and the other in static position (on the ground) .. but the leach is completely flat and closed, and the body of the sailsv and luff panel are not under tension. On the water, the feeling is to have a heavy sail with inertia when pumping, and a lot of backend pressure when flying. On the other hand, the flight is very stable, with high upwing capabilities, but the sail is not dynamic any more.
In the gusts, the draft is moving backward, and sometime, the leading edge is becoming flat again
First general conclusion
The general concept is very interessant because we have a light and dynamic sail with high downhaul tension. The global ratio (mast lenght / boom lenght) could be a bit higher on both sails, but on the 8m, this allow to keep a 490 mast, wich is good (on still could add 5 to 10cm and use a 40cm extension). On the 6m, having a higher ratio and keeping a 430 mast could help having a less stiff rig, and keep a narrow head.
The 8m2 is largely more dynamic than traditionnal V8. On the 6m2, we should probably lower a bit the stiffness of the rig
There is a problem on both sails about luff pocket / mast pannel tensions ... with cambers that don't lock (except with under downhaul tensionning). I also aim to have a draft more forward placed, and more draft volume in the head of the sail (less flat top part of the sail). That should result in
- better stabilisation of the flight (like when undertensionning the 8m)
- better upwind performance
- more pumping power with shorter boom lenght
- less backend pressure in the gusts
We could use the upper camber to achieve that if it has some pressure on the mast, which is not the case ... but we can't add spacers with that type of cambers.
Fyi, we had the same overall feeling on the first prototype of Phantom IRIS X (draft too flat and too backward). Things have completely changed when placing the volume more forward. The only thing that is very different at this point is the dynamic and ligtness of the NP sail, and we HAVE to keep that :)