servo rotation

does a swing rig, and solid rig rotate from the sail servo?
and if so, could the rotating rigs be hooked up directly to the servo…say with one of these? (see pic). somehow attach a mast to it
also, on a solid rig (wing), when going down wind, do ya just make the wing as side ways as possible?
(sorry for the lack of proper terms, just trying to figure out sumptin.)
i can fabricate stuff, but i still have to learn how to sail a boat.


here’s the site from where i got the servo extention.

I have no idea if anyone attaches a rotating mast directly to the servo. I suspect water leakage might be a problem? Straight down the shaft to the electonics?

In any case, I suspect you would be better served by one of these: you can bolt the mast right into it, rather than having to buy another coupler to bolt onto the shaft shown in your post

From the same site

In a similar vein, could you not screw a threaded rod straight into the servo horn screw hole? Not sure what thread sizes you would need, nor whether or not you need the servo horn to sit on the servo’s spline to stop rotation and loosening…

I’ve never seen a mast directly attached to a servo, Nigel…both swing and wing rigs use masts that freely swivel. I’m guessing the reason it’s not done is that it would be difficult to control the mast position quickly when responding to tack or wind changes…but that’s just a guess.

Bill H

Think you might get problems mounting the rig straight on the servo. Those poor little servo bearings were’nt designed to hold a rig up! Or am I misunderstanding something?

thanks all.
the potential problems of water leakage, servo loads, attachment, are not an issue. that’s all minor problem soving.
even the pic was just to help ya’ll kind of see what i’m yappin bout.
the only concern is the speed of the servo movement for the tacks and what not. (i know there some really fast digital servos out there).

the idea i have is to have the wing attack angles, directly controlled by a quick servo. a geared system could be used as well. (also on that site).

the main question is how these wing / swing rigs thoretically work.
i’m guessing that with the wing, on close reachin, and haulin, youve got it angled to give max drive up wind, but do ya swing the wing like normal sails, when runnin? would the symetrical shape of the wing still have anything to do anymore, or is this a down fall of a solid wing?

I think it might pay to have the wind move your sails out. I doubt one could react or even see what is required with a mechanical link between the rig and hull.
With your proposed method you would have to rotate the sail servo each time you tack when sailing upwind,everyone else merely tacks using the rudder only and the sails will flop across onto the new tack.
a large windshift(quite common in most r/c venues)will leave your sails on the wrong tack and the boat stopped.
If you are still learning about sailing boats then I would suggest copying what is known to work first before exploring the unknown without to much experience

Yoyr hulls look very nice by the way…what is your total displacment??

advice taken. it was some ideas for a cat, that doesn’t exist yet.
just letting the wheels turn.
that hull project (mr. open), has been abandoned. concentrating on aquiring some income. only so i can spend it all on r/c stuff.
however, there are some top secret carvings going on in my lab. Mwa ha ha.
something is getting primed tomorrow.

Nigel -

normally rotating masts and wings are allowed to freely rotate - usually on some type of “captive ball and socket”. This allows the mast to find it’s optimum angle of attack as the wind strength and direction varies. There is often a lever forward or rearward from the mast - rotation control - that has a line or series of lines that can be cleated off preventing the mast from over - or under rotating. I used mine on my big cat when sailing downwind (deep reach) along with a positive inhaul on the clew. This provided me with very deep sail camber for downwind work. Problem was forgetting to release lines when gybing - as a counter-rotated mast was EXTREMELY slow !


For a small r/c controlled boat, allowing the swing rig to operate off a line connected with a standard arm type servo will make sense and remove extra cost/engineering for a special servo, bearings, gears or connectors.

Take a look at the XL25 monohull page building plan and perhaps you can scale down their idea for a rotating rig since it is very simple and uncomplicated. I think this link will work and download a TIF image of building plan:

thanks again.


so, if i have a stiff pole (no jokes please) attached firmly to the hull, then a wing with a tube in it that houses micro heli bearings, and slide it onto the stiff pole for it to rotate freely.
do i then rig lines to it for control?