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[PhilandIom]

I am trying to convert a small scale model sailing dinghy to R/C. The problem I have is that the distance between the inside of the hull and inside of the deck is 25mm maximum in the centre of the hul. This does not give me enough room to fit a sail arm onto a normal servo and a micro servo is too weak to pull the sail in with a long enough arm to set the sail. I have thought about using some form of rack and pinion driven by a normal servo but would it work or are there any other methods I could try?

[Netleyned]

The Joysway DragonForce DF65
Sail winch takes up about a One Inch
Cube.
Some on Amazon with specs.


Ned

[malcolmfrary]

The Joysway DragonForce DF65
Sail winch takes up about a One Inch
Cube.
Some on Amazon with specs.


Ned

The winch body of these is a standard servo, the drum that sits on top of it is about 1cm deep and 4cm diameter.  I have seen 1, 2, 4 and 6 turn versions on Component Shop's stand.
Most servos are capable of being converted to continuous rotation and having a drum fitted in place of an arm.  You do lose the proportional facility, but with a stable power supply the results work satisfactorily, even better if the servo board is disposed of and replaced with a small ESC which can live outside the box.

[Allnightin]

If going down the continuous rotation option, I can recommend the Feetech FS90R  at £4.07 +VAT which is in the micro size but has plenty of torque  https://www.rapidonline.com/feetech-fs90r-analog-micro-servo-continuous-rotation-559636

[PhilandIom]

Thank you for your replies.
 I think having a drum or arm remote from the servo could be made to fit. I think I will try to use the complete winch servo but extend the servo drive shaft onto a cog and crown wheel arrangement taking the drive through 90 degrees so that the servo and winch drum can then lay flat in the bottom of the hull. I've ordered some plastic gear wheels from China so only a couple of months to wait to see if it will work. If that doesn't work I will try a motor and an esc.
Thanks.

[warspite]

When I saw this thread I was intrigued, on ebay replacement servos for the joysway stated that the body of the servo is indeed 1" cubed (25.4 x 25.4 x 25.4 or maybe there abouts) they are quite expensive - even at 25mm deep not including the drum that is half that of a standard servo, I have been trying to find a small sail winch and they don't seem to make any - it's torque they are after for yaughts, so small vessels like mine don't get a look in, so other than making your own, it's difficult.

[malcolmfrary]

Getting a mini arm type servo with enough torque to pull sails in and hold them in anything but the lightest breeze will probably not happen for quite some time.  Perhaps the same for really mini winches.
Going the continuous rotation route, you are really using the servo as a source of a packaged motor and gearbox, maybe with its own electronics or otherwise as preferred.  The top advantage is that by making your own drum you get to pick the diameter, so you make your own preferred trade off between speed and torque.

[JayDee]

Hello,

Have you tried sailing the boat with the sails set on Bowsies.
Set the sails on the bank and away you go !!!.

I think you should give it a try before spending a lot of Time and Money on something you may not need.
The Fleetwood Club race Schooners with fixed sails - - winches are forbidden !!.

I have a Mickey Finn yacht - -about 1 Metre long, no winch, rudder only, fair belts along !!.
Give it a go, almost zero cost.

John. 

[PhilandIom]

Hi John,
Thank you for the suggestion but I am really trying to make a miniature R/C sailing dinghy for the challenge of doing it.
Where I sail is quite a large area of water which is only readily accessible from one bank so not really suitable for free sailing or limited R/C. I already sail a One meter and a Wee nip model boat, I also race full size sailing dinghies and this is a scale model of one of those hence my self imposed challenge.
Phil.

[JayDee]

Hello Phil,

Keep posting, would like to know how you get on !.

John.

[warspite]

Just a thought - a small micro servo fitted with a self made drum with numerous windings and made to be a continuous rotator, and a spring pulley as usually set up on the continuously feed circuit driving a separate loop with a shifting lead from one side to the other (so it does not get tangled may work).

who am I kidding, I have enough trouble getting my system working, lol   

[tigertiger]

One option I have seen is to use a drum winch, and have the servo below decks and the drum above deck. The drum can be exposed or hidden by the superstructure with the sheet running through the superstructure. Another variation, on the drum above deck, is a continuous loop above deck, not too noticeable when the boat is 10m out. Larger diameter drums do not need to be as tall.