This should be interesting, looking forward to the results.
You sure are an innovator - great stuff!!
mrpenguin,
Thanks for the compliment, but I’m really just borrowing other people’s ideas.
I’m also looking forward to seeing how the boat behaves (or misbehaves). With the mast where it is the C.E will shift around, which should be … interesting? I’m particularly looking forward to seeing how it goes downwind. With the wing rotated in a proper wing sail downwind position, I’m hoping that the boat will be less susceptible to nose diving than for a normal setup with the mast located at the front of the sail.
Jim.
Tested the new sail today, footage below. I’d like to test it in a stronger wind before drawing any firm conclusions, but I don’t think that I’m getting the same power as the previous wing sails with flaps.
I made a couple of changes to be able to control the sail. The pivot point (mast) position was moved forward in the sail (otherwise I wasn’t able to control the sail downwind). And the pivot point (mast position) on the boat was moved forward (to keep C.E in same position).
Also, a clip from a test before I moved the mast. Any suggestions as to what is going on?
It is a bit hard to see your problem from the video, but I think you must have had about the same amount of sail/wing fore and aft of the mast, and when you adjust the camber, it is just folding around the mast giving you equal amounts of forward and reverse drive - thus you go nowhere but sideways…???
It might not have been clear in the video, but the boat was actually going backwards and forwards in response to slight changes in the angle of the sail to the wind.
A slight change to the last wing. I think that the soft sections may not have held the airfoil profile very well, particularly towards the top of the wing. In an effort to improve this I have replaced the soft sections with 2mm thickness depron foam:
There is a thin carbon rod connected between the top of the wing and ca. the middle of the boom. The tension on this rod gives some control over the twist.
Another small modification. I’ve added a second small boom further up the mast. This boom is controlled by the same servo as the main boom with cords running up the centre of the wing (yellow fishing line in image below).
This setup provides more control over the twist than the previous arrangement:
Tested the latest wing sail on the water. Some improvement over the previous version, but still didn’t seem to be as effective as the first couple of wings with flaps. The boat didn’t seem to point very well into the wind. I’m still not sure if this is due to the wing itself, or the position of the pivot point resulting in the leading edge being away from the centre line of the boat.
As is evident from the video below, the boat was very twitchy to sail, presumably this was partly due to the C.E. moving around depending on the angle of the wing. The wing was also prone to stalling.
I think that I’ll call this experiment over and will go back to a more conventional wing sail with a thinner airfoil and flaps. What did work nicely in the last wing was the swing wing arrangement and the servo in the wing. These aspects I will use for the next wing.
Having failed to revolutionise the construction of model boat hulls with the Lego/plasticine method 
let me introduce the foam/plasticine method.
Advantages: Doesn’t require Lego; uses less plasticine; less sanding than foam (only need to get the basic shape); easy to correct errors (put material back on).
Before and after first application of plasticine.
Hi Giligan,
Thank you for the post but unfortunately living in highly regulatory country we can’t see anything on YouTube that contains music as it blocked by a performance rights organisation in Germany called GEMA, I won’t rant over this Stasi organisation … only ask the question, does this boat sail ? (we can’t see the vid)
Jim great work, don’t give up you are inspiration to those us interested in Solid Wing sailing on RC boats.
Cheers Alan
Thanks Alan. I’m not giving up yet. But I have come to the conclusion that I probably need to work at a larger scale to make progress with the wing design. So I’ll be working on a new boat for a while.
The boat in the video wasn’t designed to float, the hulls and wing are made from solid wood.
Alan,
I guess our ‘nanny state’ is marginally freer than your ‘stasi’ one, so having seen the Youtube offering I would surmise that the model is indeed a fantastic scale model but doesn’t look as though it can sail.
Cheers
Row
Hi Jim, I don’t know if you ever caught up with guy called Dan Elliot, if not here’s the link to his Wingsail Catamaran thread, he has some really great ideas and KISS construction techniques that I think you would enjoy reading about.
Gilligan, thanks for the video file e-mailed 
Row, agree it’s beautiful looking model, wish I had the time for all that detail, but I could not just build to look at … it needs to sail !
Cheers Alan
Hello Alan,
Thanks for the link to Dan’s thread. I had seen it but not read closely. It is a beautiful looking wing, but looks a bit too labour intensive for me. I think that Hydroptere and Kampai26 on the German Mini40 forum are close to having a reasonable compromise between performance and complexity. Kampai26 has put up some video of his first attempt so that it is possible to assess the performance of the wing. The best exampe I’ve come across is still the cat that won the “Round the Island race”. If I can get close to that performance I will be happy.
Some progress on my main hull, but still need to finish shaping the bow (covered in cling wrap):
I really like this plasticine on foam method. It takes a bit of practice, but you can get a good finish, and if you make a mistake and take off too much material it is easy to correct. I have found that I need to use a straight edge to get smooth continuous curves. It isn’t a particularly fast technique, but I can work on it in the comfort of my lounge room.
Jim.
Funny that, I thought Dan’s construction technique was the least complex of them all… oh well 
Andreas (Hydroptere) invited me to met up at European Open RC Multihulls in May, I have it scratched in my calendar and will take the camera along anything special you’re looking for, let me know.?
Further details on the event can be found here https://www.facebook.com/RCMultihulls
My mistake, I shouldn’t have grouped Hydroptere and Kampai26, it was just Kampai26’s approach I was referring to. I think that it is the simplicity of cutting foam that appeals to me. You can very quickly have the airfoil you are after. How you finish the foam without increasing the weight significantly seems to be a problem. I’m quite impressed with the thin Depron I used on my last wing. It isn’t completely smooth, but not too bad. I’m wondering about combining the type of foam core Kampai26 uses, with a thin Depron foam covering. The ability of the Depron to hold its shape might allow a significant amount of the foam core to be removed.
I’d love to see any footage you take of wing sails in action. Footage of them stalling, stuck in irons, going backwards, pitch poling etc, would be particularly comforting :D.
Jim.
Just need to watch OR 17 AC 72 cat in action …they can do all of that and more !! 
Some progress on the main hull:
First image shows the set up during the polymerisaton of the hull. The second image shows the hull and deck (still over foam/plasticine mould) with the deck undergoing final hardening. Still need to complete bow and stern.
The plasticine/foam method worked very nicely. Once the hull had set it was trimmed and then the deck shape was moulded in plasticine (same method as used for test of Lego/plasticine).