I am new to this sport So sorry for stupied questions. [:-banghead]
But i was wondering if anybody have informations on how to build a winch out of a normal servo ??
One on my friends told me this is possibelâŚ
Since i don?t have so much money it would be grat to do this.
There is a site on the web that tells you how to do what you want, but off hand I canât remember were it is. I have read it myself in the past but it was really technical and at the time I was not up to understanding it. The only trouble with it is that a sail winch rotates 41/2 times, where as, one made from a normal servo, the rotations are endless.
Peter
Thanks for the fast replysâŚ
I will try to built on on me own, if it does not work i can always ugrade to a real winch. [:-bigeyes2]
If any of you guys find the site where it is explaind please post the link.
The links are servo-modification links. If you pull the feedback pot out of a servo, youâll get endless rotations. Iâve used this for radar masts, etc. Also - pulling the gearbox off entirely and using the motor output is a cheap way to power a tiny scale powerboat.
By changing the feedback pot or the inline resistors, you can modify the number of turns, but itâs a âhardwiredâ solution, but itâs cheap.
This page has more R/C links than youâve ever seen, and there are servo-mod links on here. There are more sites, but this is a good place to start.
The size of the servo required depends on the application. However, anything smaller than standard cannot be modified, unless you go outside the case to position the potentiometer.
Speed is the next consideration. For high torque and fast speed in a One Meter (IOM, USOM) that allow drum winches, I have been modifying the Hitec 5945 digital servo. If you have room and weight is not a problem, then you can use the Hitec 700(old), 705(slow), or 755(new) or the 805(mega). I have sped up slow winches by using 7.2V pack with two connectors, one across 6 cells for the servo and a separate pigtail off of 5 cells to go to the receiver. The only wire connected from the servo to receiver is the signal wire.
Rotation is the other consideration. I use digital servos and a computer radio. So, I can program the servo for a number of rotations and fractions, and then fine tune the degrees with the transmitter. Of course, this is all done after exchanging the servo potentiometer for a precision wire-wound 10-turn pot for big servos with room inside, or a high quality (BI Tech, M/E) multiturn square cermet pot on smaller servos. The value of the pot will determine the rotations and the width of the deadband (in degrees). The lower the resistance the better the deadband and the higher the potential rotations. I use 5K or 10K. Do not use anything less than 5K; a ten-turn 2K pot will give a very narrow deadband of a fraction of a degree, but go off the end of the variable resistor. At the other end, a 50K ten-turn will give 2.5 turns, but have such a wide dead band, the line will creep out a inch or so before the signal kicks the motor into running again. Wiring on Hitec servos goes: green to 1, yellow to 2, and red to 3 on Clockwise(CW) pots.
Mounting the new pot and connecting its screw or shaft to the drive gear is the most tedious task. I use contact cement to glue the new pot on a small plastic circle that fills the spot where the old pot used to be. For the small pots, I construct a plastic rod to connect the potentiometer screw to the drive gear. Both ends of the rod look like slotted screw drivers, one large for the gear and one fine for the pot screw. The connecting rod and the head of the screw go through a hole in the plastic circle and connect to the key in the drive gear. The connecting rod has to be the right length. To help maintain the connections at either end of the rod, I use a drop of industrial contact cement on each surface. I have used a brass strip as a connector, but the end in the gear needs to be built up, and the end on the screw of the pot must be soldered to the screw quickly or the heat will melt the case of the potentiometer. The shafts of the larger (5/8" square) pots for larger servos have a 3/16" shaft that just needs a keyway cut on the end for the drive gear. The empty space around the pot, in the servo case, is filled with form-fitted high density ârubberâ foam that prevents the pot from rotating when driven. Button up the servo, put on the drum, and go sailing!
I have a 5801, Whirlwind low profile, Graupner Regatta, Tony Able that all can be adjusted with a turn of a screw. I have modified a transmitter for one of my 725BBâs but it sure would be nice to be able to just turn a screw. I have new ones that I am going to put in my Atlantis and I am building a boat for a friend who has a 725BB for it. I have contacted HiTec 10 years ago but canât find the reply. Ken Binks offers them modified but I already have them. From what I see on two or three forums a lot of people would like to be able to do the same. I also have two computers transmitters but that doesnât help the boats with the 725BBâs. Can anyone help?