David

I added 2 views of the junk wing demonstrator showing the sheets and span (thin black lines). I wanted to add a scheme but it was not in the proper format. I have a span between the end of the batten and the end of the wishbone part (70%, same batten). The spans of a pair of batten are linked by a span (as standard), but the top batten which is alone. I connected the spans and sheets with rings (adjustable but not running free).  

As the inter batten span and the sheets are more forward they don't trap in the rear of the battens. Both spans ( intra and inter batten) are too short (when not reefed)  to get in the battens' rear. The difficulty should be divided at least by 2, I think. 

Eric

Bonjour

This topic was initiated around Mingming's change of owner to my benefit. 

http://www.junkrigassociation.org/noticeboard_forum/3116356#3169628

I'll start from the beginning to try and explain my approach.

I have no junk rig background. As Roger's friend and Roger's book's translator to French I was introduced to junkrig. My background is much on Bermudian rigs, old gaffers... 

The evolution of junk rigging in western countries by introducing stiff (articulated or not) battens puzzled me. My engineering back ground tells me that soft and stiff hardly coexist and that stiffness leads to stiffness. 

The issue is that with "classical" junk rig and flexible battens the more wind you have the more camber you have. Unfortunately cambered sail are efficient in light wind and flat sails are efficient in high winds. 

I tried and find a flexible solution that would, at least, maintain the same camber independently of the wind force.

My first idea was to forward the sail to have the mast at the level of the drift force (one third of the profile). It would use the forward part of the batten (the most important) to flatten the sail when the wind forces and by reducing the effort on the sheet reduce the cambering effect on the rear part of the sail. 

The second idea was to forward the sheet on the batten, let say to one third of the leech, The rear part of the sail would counter the flexing effect of the sheet on the battens. In high wind it would introduce a non optimal S shape of the rear part of the sail. 

The third idea was to use two sheeting points on the batten, one at the leach and the other one forward. The penny had dropped... 

The two sheeting points would be linked by a sling and the sheet would be attached (free or not) on the sling.  

The "price" to pay is to have a starboard sheet and a port sheet. 

Eric

PS : Sorry I don't know yet how to add a file or image.