it what I had laying around in my pile of CF…plus with the tubes I can put a cotter pin in the top of each mast and use a length of line to pull the tops together and then another line to the deck for the forestay. so no having to drill into the rod/tube for fittings.
Marc, what do you mean by the reference to ‘too much tension’?
You appear to have only constructed the mast and in this rig arrangement the design goal for the mast would seem to be a structure that is able to take the loads of the forestay without undue flexing etc. and that implies a fair degree of tension? Isn’t sail shape achieved through the usual leech line and foot adjustment?
Am I missing something?
Ray
Claudio,
I pinged you a PM about the Alinghi 5 drawings in AutoCad format but haven’'t heard back - did you forget me? Cheers.
Regarding the delta rig concept; you’re experiments seem to have been with what is essentially a una-rig. At the speeds our boats work at there is something to be said for seperate main and foresails so that you get the benefit of a slot - have you considered/tried this at all?
Ray
I’m sorry Ray,
the Alinghi-5 plan, under DXF, PDF and Jpeg formats, was adressed to your mail at least a week ago.
Missing some where !
A send it again hoping will pass.
For the rest, the Delta Rig is totally a different concept, except that on my model I use the swinging boom. The CE remains close to the boat.
The eventual gain coming from the slot of a Tuna Rig, which need to be proven yet, will be lost anyhow with interests, by the turbulences induced by the mast.
The specific design of a “Delta Rig” is remarked by the total absence of mast interferences.
The security, on real boats, is also achieved with a simple jib roller.
Cheers
Claudio
PS: the file is of 2.1Mo
ray,
the mast once the glue set were angled aft about 5* which I did not care for. but I went ahead and put the forestay on and brought the top of the mast even with the transom. by using the forestay. which resulted in bending of the mast and an extreme amount of tension in the forestay… so much tension that I doubt the rig would swing freely in light air…
tension is a good thing… but too much is just as bad as not enough…I could pluck a tune on the fore stay…
Thanks Claudio for bringing this up. It’s ideas like this that make me excited about sailing. Make me wonder how a delta rig foiler would fair.
Claudio, many thanks, I got your mail this time. I don’t know where it wen’t last time - it didn’t even get to my spam filter.
Anyway, thanks once again, I’ll enjoy considering possibilities…
Ray
Marc, perhaps the forestay tension wouldn’t be a problem if the sail could rotate about it (i.e. give the sail a pocket luff). Is there really any difference between a forestay under tension and a stiff conventional mast? Remember, the aim of this sort of rig is to improve the efficiency of the sail by removing the poor aerodynamics of a typical mast arrangement.
I need to think more about Claudio’s swing rig approach as I suspect going to a conventional jib type sail format, perhaps with several ‘foresails’ might be simpler and easier to set up and tension should be less of an issue.
Ray
Marc,
I was thinking CF rods, because you could form them into a real wishbone shape (1/2 each) before attaching to the hull. Then form oval collar(s) to slide over the pair to attach the halyards.
fwiw
I was working on a solution concerning the sail arrangement and the servos set-up.
the 1st picture represent the General Plan
the 2nd picture identifies the difference between a classic Bermuda rig an the Delta rig for the same sail surface.
the 3rd picture shows possibles solutions to control the Sail position - I choose the Option B that is a mix between the top rail and the deck slide.
the 4th is showing various details concerning the servo and sheeting arrangements.
It is not escluded some modifications as soon the assembly work is progressing. In spite of previous model called CD-CAT, this is just an experimental boat of this size and changes may occurs.
See later
Cheers
Claudio
Today I spent some time to prepare the Mast set-up and integrating a couples of frames as support for the forestay
Claudio
look nice claudio…I’ve been trying to figure my ec12 issue so haven’t had a chance to screw around with the 507…
The progress is not very fast, nevertheless some verifications has been made.
Definition of the winch and battery position compared to the fin.
I used the bathtumb while She was shopping !
The boom is laying on the top in order to distribute the weight.
The winch and battery + Rx will stay on the fin sides.
The drawing shows the definitive set-up.
Another aspect concern the boom-sail orientation when close-hauled.
I assumed a 12° boom opening and 27° for the apparent wind direction from centreline. The course is assumed to be 4°.
The true wind is assumed to be at 45° from the sailed course.
Obviously all that will be verified on the water !
Now I will mount the winch and setting up the travel string including blocs
Claudio
Claudio-
Perhaps your next project would be a test tank? 
I think I will try this with my Papaya hull-
Did you place the mast and sail in the usual way, after figuring the sail CE, etc? Would you say there is a practical ‘maximum sail area’ for the Footy?
thx
Hi Tomohawk
somebody has already done it. It was like an oval ring where an outboard engine of 4hp was installed with the propeller to move and circulate the water while the model was keep steady.
Filters/grids of various sizes where also introduced to reduce the turbulences and a sort, of self made, balance was mounted.
The results were not very conclusive as such to discourage further developments for the time being !!!
Cheers
Claudio
Pics:
Design drawing & water tank under construction
I would think that an electric trolling motor would provide better results than an outboard engine…plus less noise, and with the proper cords you could probably get it to run off household current with a converter…
I do not intend to go Out of Topic
just to says that it is not easy, since all the water mass shall renewed at the speed of minimum of 1m/s !!! (3.6km/h)
it is needed to calculate the volume of water you need to move at that speed and the power …etc…
Claudio
CE and CLR are positioned as usual.
I ignore the footy capacity to accept single sail area.
Claudio
You are correct, Claudio, about the water tank.
People seem to forget how difficult it is to move water, and how much energy moving water carries with it.