Ash Woods wrote:

One quick question please David...How does the new wingsail behave when spilling wind - during raising, or reefing; do the single sail and batten aft the hinge points, flog or rattle in stronger winds?

Thanks.

Ash

The sail is completely docile when feathered into the wind. No flogging at all, because it's cut flat, and no snatching or rattling. Just a gentle "clack" when the sail fills and the hinges come to the end of their travel.

Off to THAT forum :)

e

David Tyler wrote:

Erik and Evi,

Reply is in the wingsail forum.

Where would this wingsail forum be lurking?

David - A big congratulations on the great looking sail.  Loved the pictures you posted.  Questions abound  :).  

• Have you had it out in a breeze (20+knots) and how did it do?  
• Does the sail have less drag than a standard sail and were you able to reef later if at all?  
  
• Does the luff stay straight between each wing frame as the wind increases? Or do you need a a downhaul to keep the shape.
• Curious about your choice of cloth and weight.  Seems stout.  Are the loads expected to be higher than on a junk sail?  Weren't  your original wing sails made of dacron and isn't the current cloth choice less stable on the bias?
• Do the flat aft battens put much downward force on the hinge?
• How are the parallels or their equivalent rigged to keep the sail wrinkles out?
• More questions :)
  

If you've not seen it, here is an image of a full wing sail called a Soft Cell sail. Nothing hidden given the sail cloth choice :)

We are still planning on converting our Freedom 40 to something different than the current wishbone rig.  The characteristics of DIY, simple, and performance all being important and cambered junk sails leading the charge. Your design does appeal though, not only for its performance but also the aspect ratio and resulting sheeting angles may be easier to deal with on our ketch.   Its been great though to sail it in the current configuration and learn (esp that we want to change sails).  We've had our boat out in various weather conditions and are quite happy with the way she performs.  Even did several races - the longest and most fun was 70 miles downwind, 7 good friends and three 3 dog, 11 hours.  

Cheers,

Erik and Evi

David Tyler wrote:

John,

The main difficulty was to make joints that were strong enough and resistant to cyclical loadings. The bridge pieces behind the mast were rivetted on, and loosened. Welding would soften the alloy. If I made alloy noses again, I would try to bend them around in one piece, rather than rivetting on a plastic piece at the luff. This, I think would be hard to do, as the tube has to be over-bent and then allowed to spring back. It took me a while to develop a former shape just for the nose made from two pieces of tube. It would be as big a development job to develop a former shape for a one piece tubular alloy nose as for a CFRP moulding...

David,

I know this is water over the dam for you, but if one were experimenting with making the wishbones of aluminum I wondered about making the nose piece out of bent aluminum tubing, separate from the long pieces. TexasTowers.com sells 6' and 12' lengths of AL tubing from 3/8" OD to 2-1/8" OD, by 1/8" increments, with the wall thickness of all tubes 0.058" (which is just under 1/16"). Thus, all tubing sizes telescope into the next larger/smaller size. So you could bend the nose pieces out of tubing one size smaller than your main battens, and either rivet, screw or bolt the wishbones and nose together.

URL for 6' lengths

http://www.texastowers.com/aluminum-6.htm

For the strut that you are thinking about placing aft of the mast I wonder if lashing it to the wishbones would a be useful alternative to welding or riveting (which you can't do for CF, but tried for aluminum). Aluminum tube skin-on-frame kayaks sometimes use lashed joints. Here is an example of one. I could imagine lashing aluminum tubing, aluminum channel, HDPE shapes, or CF or GRP shapes where you want a very strong but resilient joint.

http://s13.postimg.org/7066sj0w7/Lashed_Frame.gif