For what it's worth, I'd stay away from a wingsail for a one design class from a commercial point of view; Beneteau are already well down that road.

If I were designing a one design I'd take a leaf out of the French racing scene.  A Boat of about 9m with canting keel and daggerboards.  I'd use a cambered panel junk rig.  Carbon mast and battens with dyneema running rigging, state of the art sailcloth etc..... and I'd make it a BIG sail.  The mini-transat class carry around 40 sq/m on a 6.5m hull... which is why they can reach 15kts downwind.  Scale that up to a 9m boat and you've got an exciting downwind flyer..... and it still fits in a container for shipping.  The mast tilted forward and you have a distinctive looking boat that can be powered up to really fly off the wind.

Peter

 

Paul,
if I got it right, then your proposed wing section should look something like this. I like the idea of making a tackable wing with no mechanical hinges, just the stiff wishbone, ABCD. The tacking main section (EBC on this tack) should touch the wishbone a bit forward of B and thus close the gap. This should give a smooth wing on the leeside, all the way from the blunt leading edge to the leech.

The question is how much damage the hollow aft of BD does to the airflow on the weather site of the sail. After all it has to be about ‘two cambers’ wide, so there must be some drag from it.

Below your section is the section of a Ljungstrøm sail. Ljungstrøm created the important round leading edge and smooth leeside by rotating the mast so that the mast track was pointing forward. He was much aware of the turbulence behind the mast on the weather side. His conclusion was that due to the much lower airspeed on this side, the turbulence would do little damage. In practice, Ljungstrøm’s sails were more close-winded than the Bermuda rigs (sloops, mainsail and jibs) of those days (1930s).

I think you have come up with a very interesting idea  -   good luck!

Cheers, Arne

 

Hi Ash, I hope to make a complete set of 'fish-tail' battens next year sometime. Meanwhile if you look up my AeroJunk you will see that I have wishbone battens and inside them a separate jib and mainsail.  On each tack the mainsail blows 'inside out' and follows the leeward side batten. This present experiment will replace the 'self-tacking' jib with an external wrap-round jib that overlaps the mainsail by about 30%. So on each tack the sail(s) on the leeward side will be continuous. On the windward side there will be a hollow where the jib leech stops. This will produce some turbulence on the windward side that should curl back into the hollow space allowing the outer wind to flow over and continue. Meanwhile the leeward side will be smooth and fast.

It sounds weird but I see no reason why it will not work. Then next year I will make a new set of fishtail battens and this new wrap-round jib will be the front half of the new sail. Then I just need to make a tail section.

Tell me if that is enough for your experiment or if you need more.

Cheers, Paul

Thanks for sharing Paul. I have a sail maker in China working with me. We can do the experiment also. John

David, You're right it's a junk for the people. I have been racing round the cans in my 28 feet Impala for years and never tired of it. I will pay attention to the budget to make sure that she's affordable. I still want to explore into the possibilities of soft wing sail for a while as a modern version of the Junk Rig, because Chinese always like new ideas and won't appreciate their own culture.