airsail said..
The 914 is a great wing but more flat water oriented. Put it in good size swells with rapid changes of direction and it falls short, likes a more drawn out gliding turn rather than snappy changes of direction. The Mach 1 900 is very similar in shape, but with the very thin tips of the 914 cut off. Both are heavy wings, solid carbon.
I'm sure cutting the tips off the 914 would bring it's liveliness closer to that of the Mach 1 900.
Interesting. Did you have the stiff C100 mast? I think a flexi mast is a real problem if seeking snappy response to roll changes. Also what length fuselage with the 914?
If you cut the thin tips off the 914, then I guess you'd gain roll agility, but lose low speed lift and ventilate the tips easier and lose pitch stability - because the washed out/up tips help pull the foil out of high speed dives.
I used the 914 mostly with the short fuselage (56cm I think) and the carve turn radius felt pretty tight to me. In my experiments, small change in fuselage length has a big effect on the turn radius. That was keeping the position of mast to main foil the same. Shorter (stab in) is always better in slow surf waves. Even in flat water, I never liked the rear position on the longer 64cm fuse because the turns were too wide, like a long wheelbase bike. With the 914, I mostly used a cut-down 280HA rear foil. I guess it'd be a 250 "MA" and that noticeably helped roll agility and was very pitch stable and relaxing at higher speeds. But clipping the tips of the stab foil lost me a lot of yaw stability which created serious ventilation issues with the C100 mast. I tried a lot of things (various sanding and also adding to the leading edge to sharpen the entry), to solve the C100 ventilation issues, but did not succeed.
I did an interesting experiment with the 914 by adding about 3mm to the leading edge to sharpen the entry. Fairing the section shape what I thought looked nice, and final finish with durapox paint with my usual 1000 grit finish. Hoping for higher top speeds, since it used to hit 27.0 kts so many times like hard barrier. The result surprised me big time. My 914 became much slower. I'd guess 3 or 4 kts slower (heaps). I guess that I positioned my new/shaper LE a little too high and destroyed the original pressure gradient over the whole foil. But I'll never know now, since I sanded that addon off, to restore original shape, and the original speed came straight back. Showed me how subtle the foil section designs are.