How about some pics diagrams on servo setups to function as winch?

We've seen standard servos used to sheet in and sheet out using conventional RC servos. They can be fast and they provide very good control. But you need some pretty heavy duty torque for a surface sailing model with a mast over 24 inches. Go to IRCSSA.Org to determine the class you are interested in. The class is determined by the theoretical box you could put a fully assembled surface sailing model into.

My son is developing and selling the RCWindjammer; a model sail car with a mast 6' tall, an overall length of 44 inches and a beam of 38 inches which serves as a pretty good stable base in brisk breezes over 8 MPH. (He adds weights when the breeze goes over 12 MPH).

To control the sheeting (sail in and out) he has selected the HS-725BB from Hitec as the ideal sail winch. It has a drum and can pull or release about 12" of sheeting line. Here's a picture.

Wayne

Wayne: FYI @ son's site serov details from image is not functioning.
http://home.att.net/~rcsailcars/specs.html

Hummm can almost visualize a SimplePlasticSailcarDesign (SPSD) showing up in the SPAD threads!!!!

I converted a standard futaba servo to winch type, it's not particularly powerful though, so i'd only really recommend using it if you're using a relatively small sail area or have light winds. it works find when i use it for my ls-4 with wing mast only. i do use it when i have the mast & sail, but it struggles when the wind picks up.

I'll write a short explanation of what i did.

when you open up the servo, there's a few cogs at the top, the motor & a potentiometer in the middle, and usually a circuit board at the bottom. now... from memory, where the cogs are there was a small black plastic cap type thing, it basically turned the potentiometer when the servo went round. i had to drill and cut a small tag from the centre of this black cap, this stops the potentiometer from being turned, and the motor is free to continue one way or the other.

there, real easy i know it's not much of a description, but if you open up the servo it may seem a bit clearer.

those little tabs that stop the over turning of the servo are cut off?
Then tech. the servo will spin faster as you advance the stick.

so its the wind itself that determinds what direction the sail will swing out. So that means you don't have to have left and right just one way that rolls in and the let out. true?

A winch would give more travel than a sail arm, but how much is really needed?

Nathan:

that's right, the more you push the stick up or down the faster the servo turns. and with a winch servo you don't have left and right, you have roll in and roll out or the sheet, just like a real boat has, you let the sheet in and you let the sheet out.

HobbyBob:

how much travel you need depends on th size of the landyacht, the reason i like the winch is that i can centre the stick and the sail stays where it is, it doesn't return to the centre like an arm version would. it also means that you are not consantly draining your batteries. an arm servo is drawing power whenever it's not centred.