according to physics yes , no reason to be different. This is an architectural book highlight !
To avoid main boom upstream flux I equipped one of my RG 65 of a special blade. One of the most famous counteract solution was adopted by Enterprise and another AC with the introduction of the called “Park avenue boom”
Cheers
ClaudioD
Very interesting Claudio, looking at the pic with the boat in the water, is that a line holding up the mainsail head, at the leech ? (under the head crane)
Cheers Alan
was a piece of elastic, but was not working as expected
cheers
ClaudioD
PS: just a simple exercice on a sail design about sail’s shapes and CE
Hi Claudio,
I’m tending toward the narrow head main, only because I have yet to figure out how to configure a wide head main that will hold up well … any ideas ?
Cheers Alan
Hi All,
What I’m posting here are some pictures & illustrations of my observations on SUI-100 Jib set-up, something that I think is an extremely good idea which was designed and developed by Matthias, owner & skipper of IACC 120 Alinghi sailing team, Italy.
What needs to pointed out is this innovative idea alone is not the “big advantage of his Alinghi fleet” as Matthias quite rightfully says about his concept, it has taken a long time for him to refine his ideas together with other many aspects that have resulted his fast and extremely well tuned boats and is within class rules…. And that is what I love about this class, the flexibility to come up with new ideas.
Matt has copyrighted this concept but allows people to use it that are interested by simply requesting his permission and for personal use only, it is not available for business purposes. You can contact him via PM here or at http://iacc120cup.altervista.org/ where there is an English speaking section. With his small high tech workshop, he may be even able to provide some boats, ask him !
The very first time I saw this approx 18 months ago I was instantly intrigued with this “different” idea for RC sailing boats using a Jib boom, you can study the attached pics and come to your own conclusions, I will not attempt to describe how it works, he used the KISS principle which is hopefully self explanatory by pics & illustrations attached.
Bravo Matthias :bravo: I tip my hat to you for what I think is a brilliant idea which makes it all a little harder to have you in our wake …but it can be done as proved by BMW USA 17 and Shosholoza 09 …it is just a question of how much more has SUI-102 improved over SUI-100 and I’m sure Luca and others will have something up their sleeves too.
Conceptually when I look at these pictures & illustrations, I’m asking “which one would be faster” what do you think?
Cheers Alan
Apparently Mat should tell better since is managing well even with strong wind as seen in Ravenna except some visibles fluttering in the films .
Also my self I will modify the sail of my AC100.
Cheers
ClaudioD
PS : your last picture above shows a tremenduos distortion of the main in the boat at right and in the middle, while is ok on the left one !!
I’m not sure that adding a third line (the additional forestay) to divide the backstay tension three ways, is a good thing. I think you will lose control of the jib luff tension unless you use higher backstay tension that will bend the mast more than normal. At least for classes such as IOM.
When a puff hits the jib, the leech pressure will try to lift the aft end of the boom. This will increase the tension on the jib luff … a good thing. With the added forestay out in front, the increase tension will be on it, actually loosening the tension on your jib luff… not good.
Am I correct in this thinking?
Hi Hew,
When your talking IOM “flexi masts” I think you are right …but when you can use a “stiff mast” (post #38) as in IACC 120 class, it appears this may over come this issue.
Claudio’s sail plan comparision above has convinced me to move away from square head main, and go for the traditional sail plan with lower (-70 mm) C.E sail plan for better sailing stability.
Cheers Alan
I did the extra fore stay a couple of years ago. Doesnt work as well as you would think. when you tighten the extra stay the luff of the sail looses tension. Build one and adjust it, you will see pretty quickly what happens. If you want the jib luff on the centerline of the hull, then you really need to do a radial jib.
Hi Slotracer, Yes I can imagine it would be bit of a balancing act, I’ll leave it for now and just work on getting my basic rig right first before playing in the unknown.
Cheers Alan
Hi Alan,
I found some basics rig adjustments used on Thunder tiger’s 1 meter ETNZ looking close to real boat one’s and that could be improved on IACC 120…
As it seems to work with an ABS mast, it must work even better with carbon.
They’re also using a “Sail Wire” to hold main sail’s top.(page 14)
There might be some good things in this configuration, even if most of R/C sailboat builders should consider this boat as a toy.
Happy new year,
Paulin