Sandman1221 said..
For everyone, Andy the owner of Wind-NC, until recently, once told me you need to get 10 mph (8.6 knots) forward speed to foil, so according to that in 8-9 knots you do not need much additional speed to get up. I never asked him where he got that number from, but he seemed very certain of it, and he was an avid foiler with access to many different foils.
Of the 3 boards that I've foiled regularly and the 5 or so front wings, the board speed tops out at around 3.8-4.1 knots measured by a glance at my GPS watch. If I get to that board speed without pumping I know that I can get on foil, regardless of sail or wing size, but the <900cm2 wings are a lot of work. I've completely changed my pumping technique to take the work out of irritating my biceps tendon, and can pump a lot longer now, but Balz and the rest and many local foilers here put me to shame on smaller gear. Everyone I know uses balanced lines. I have even shimmied them in flight to correct them because the unbalanced feeling is noticeably more work vs just using more hips to trim.
The phantasm 926 which is closer to your larger afs and i76 do fly around 8knots board speed or so, but full body or out of harness pumping is required to get there unless it's almost planing wind speed. The small race foils like the 650 get a nice semi plane with a 9.0 in 15 knots of wind, maybe a little less or so but even then they need to be urged up actively.
I have on very flat water pumped the sail up to the hull speed and onto foil but not on my flat freeks. It really requires good timing and coordination on a cammed sail to keep the momentum up. I've gotten the uncammed sails flying but they lose their belly immediately in light stuff, but I think that could be remedied by stealing Balz's brain. It would behoove you to measure speed or record anything in some reliable way, as I've often found what I think I'm doing vs the measured result is totally different.