Rudder & Winglets

Here a shetch of what could be a rudder equipped with radio controlled winglets .
Manual control option with nut and counter nut on the treaded coaxial rod. (not in drawing), or a long screw acting on the winglets crossrod in order to adjust the tilt angle.

Another view

looks like a neat idea, im not sure waht itll help you with, but itll be neat, you can make some adjustable hydrofoils like that tho, would be sweet

Claudio -

Doug Lord uses a similar arrangement for the rear rudder on his F3 Foiler. See Microsail’s web site. His front foils are controlled by “wands” toouching the water’s surface.

thanks Dick,
found and interesting specially the one used on the Moth model.
On M, unfortunately, the rudder on the stern is forbidden as well the winglets on the fin.

Here the new rudder design concept.
The rigid rod controlled by a servo, is replaced by a flexible cable and a pre-loaded spring. The servo is not needed anymore. the incidence control is assured by the Swing-rig rotation or better by the mast to wich the cable is attached. One or two degrées of mast rotation are sufficients to relax the cable and adjust the maximum incidence during running and reducing it (by pulling) to zero during close hauled.
The flexible cable can be easily disconnected from the pulley and the full rudder assembly removed from the hull.

Claudio -

I like this engineering solution. Get’s rid of servo and battery weight - as well as an additional channel on the radio becomes available.

I didn’t look - but maybe the 10Rater class rules would allow this?

suspecting the Class M Rules interpretations, where the appendages shall not be “articulated or retractable” , and in spite of the fact that the rudder is a movable part, possibly articulated via a rotary joint, I wrote to the ISAF Technical Comitee Chairman Mr; Grubisa asking about.
Literally the “antonysm” of “articulated” is “Fixed” - The rudder is not.
The rudder, in my opinion, cannot be considered a “fixed” appendage, and by consequence also the movable winglets attached to the rudder .
I also believe that this Rule was introduced with the spirit to avoid pendular and retractable keels only.
Ok , anyhow whait and see

As already reported in an other thread, Mr. Grubisa, Chairman of the ISAF TC,
has just confirmed that moving winglets/ailerons attached to the rudder are forbidden in Marblehead Class, while the fixed winglets/ailerons are permitted.



I just love it when a class bills itself as developmental - and then throws out a ruling that you can’t be innovative. :mad:

Maybe the class needs new, younger thinking that isn’t stuck in a groove. Just another example of why some classes keep shrinking. You can BUY your way in with a $3,000 plus carbon fiber boat and all sort of carbon or titanium parts but God forbid if you come up with a simple and inexpensive idea to prevent nose-diving.

I just don’t get it - nor do I really want to! :rolleyes:

I agree Dick, is very frustrating.

I used various arguments including the technological boosting that the class will profit upon, but does’nt work …It was reported to me that in Italy the Marblehead is disappearing due to costs, but, the IOM is costing more and more almost as the M.
Modelling is not only a base for leisure but also source of progress innovations, but the “responsibles” do not care, unless the others “big” suggest something new.
In spite has been suggested to go on the 10R that after all is using similar hulls.
Today I’m busy with the potential application of the Memory Wire to activate the winglets movement, ( ~2mm) - any experience on that ?

Nope - sorry. First I heard of it was your earlier post.

The work is progressing, yesterday was the balsa shaping, during night the carbon skin polymerisation and today the rest so far :

By the way , in spite of precautions, the original spring was glued, therefore I was obliged to a chirurgical intervention and put a new selfmade spring. Good to knows for the next time, the window will be covered with a very thin sheet of brass or alluminum on both sides.


The rudder is mounted on Studio3. 3? between the two photos

Claudio -

thank you once again for the fine photos that describe your ideas. I almost wish you lived closer - I would like to see some of your inventions and ideas in real life. Hmmm - maybe a trip to France perhaps? :smiley:

Why not Dick after all, Nice is probably some 10 hours flying from Minneapolis.
I spend more time in various trials than being on the water, like with my old maogany Dragon, 10 hours of maintenance per 1 hour racing, actually sold. Is time to reverse the situation.
Next is to find the memory wire …and ss spring to avoid rust.

NEW discovery !!
Shaft Adaptor for Hitec.
With this device short displacements are possibles visit here :

And here instead another device for semifixed adjustment using the Rudder arm , it may be rudimentary but it works


Hi Claudio,

Just had a thought - Could just fix the wings and move the top of the rudder shaft back and forwards a few millimetres? This would change the wings angle of attack and cut the engineering in half.

Love the delicate engineering and photos.


didn’t read the post date - -2006!!!

Yes of course, tilting the rudder shaft will produce the same effects, but mechanically complicated.

Me too I cannot read the link anymore