Statistics: Posted by AYRSwebadmin — Fri Feb 02, 2024 9:46 am
Statistics: Posted by Robert Biegler — Mon Dec 04, 2023 5:54 pm
Statistics: Posted by Heimfried — Sun Oct 01, 2023 5:21 pm
Statistics: Posted by Heimfried — Sun Sep 24, 2023 7:08 pm
Statistics: Posted by Robert Biegler — Sat Jul 29, 2023 12:32 pm
I was quite surprised myself.I would imagine that is good and I am surprised that despite this you say that the foil was sucked down when sailing dead downwind.
No, I was still referring to the foil. Think of the junction of the foil to the strut. Pitching up lifts that line. Toeing in keeps the line at the same pitch, but the forward and comes towards the boat. With the foil slanted about 45 degrees at rest, pitching up 5 degrees should have much the same effect on angle of attack as toeing in 5 degrees, but it has different effects on the strut. Only pitching up will make the strut lift when running dead downwind. My hinge axis is also angled, so that it makes the foil swing back and toe out as well as pitch down. I hoped that, at a moderate heel angle with the foil to weather, that line at the junction would be level and the foil pitched down. So for the at-rest position, I reversed the effects of heel on both pitch and yaw.By toed-in I am guessing you mean that when looking down on the boat the hinge axis of the foil arm is not parralel with the hull centreline
From the drawings, his boat was about three times as wide as the rig was high. That gave him a foil that started off much closer to vertical, so even though his hinge was far outboard, his foil had more reserve before it went flat.You said in an earlier post that if you positioned the foil arm hinge further outboard (as for the Whitacker models) then heel of the main hull would soon make the the working part of the foil horizontal at which point leeway would not generate the requred downforce component from the foil. From seeing Giles Whitaker's films, many years ago now, the fact was that the heel stabilisation provided by the hinged foil was so effective that the main hull never heeled much even in waves which if scaled up to full size would be a pretty rough sea.
I have worked out a hinge with two degrees of freedom that could be used both to control foil angles better and to fold up the foil in harbour, but if I exploited that foldability to make the boat much wider, I am not confident the boat would tack.The wide beam is perhaps discouraging but the arms holding the foils could be made to fold in for berthing.
Do you remember whether those films showed the models tacking or gybing, or even changing course from on the wind to a broad reach? Giles used foils on both sides, so he could not put the rig between hull and foil to get the lateral sail balance right. Giles wrote that the foils "must be adjustable fore and aft while sailing in order to balance the helm". None of Giles' models has anything that I recognise as a mechanism for doing so while sailing. And I would be surprised if they could tack.in the short films I remember Giles showing at an AYRS meeting in London the main hull simply did not heel!
Fixed.The first of your two referenced U-Tube videos shows your boat sailing very nicely with the foil on the lee side but the second video does not seem to display, presumably a broken link?
Statistics: Posted by Robert Biegler — Sun Jul 23, 2023 9:32 pm
Statistics: Posted by John Perry — Sun Jul 23, 2023 4:15 pm
Statistics: Posted by Robert Biegler — Mon Jul 17, 2023 7:47 pm