High-Speed Sailing

This third diagram shows the airfoil rotated with the tip less to windward (less tilt). Again, everything else is the same. This time the resultant produced by the misaligned foils is now a "down" force shown by the red arrow at the airfoil. Once more our craft is not roll stable and it will roll to leeward. In both this and the preceding diagram the roll center is at the windward hydrofoil. Whereas in the preceding case, the lee side of the craft can be lifted off the water, in this case the lee side will get depressed into the water and if the force is great enough, a pitch-pole and roll to leeward may result. (I tell ya gang, there's a lot of fun left in this game.) I can tell immediately if the inclination on Sailien's airfoil is not great enough, because the forward-most of the two lee foils gets depressed into the water. This happens at low velocities and is easy to see.

Now let's see if we can apply this information to Sailrocket. These diagrams apply to my post of 09 Dec 08, "More observations on Sailrocket" so compare them with the text of that post. If Sailrocket is set-up with too little inclination of the wing, they could easily bury the lee pod at low speed (soon after starting a run). There is a danger of the craft rotating off the wind at that point. If they get the lee pod planing, they may be ok but we will have to wait find out.

Bob