which servo is the most powerful... ie being able to push-pull the most weight.

jr 8711 403 inch/oz of torqu on 6 volt


http://www.horizonhobby.com/Products...rodID=JRPS8711

This is the strogest i know of...

thanks,

Is this just a question out of curiosity or do you have a project in mind?

There are actually bigger servos available then what we use in model rc.

well actually yes... long story made short, I am working on a autopilot for a 21' Boat. got most everything figured out except how to make the boat's steering move... hence the question. Where might I find the more powerful servo's. might be useful for robotics as well, or maybe I might be a little slow on the thought process. would they be easily controlled by a RC type of voltages and signals or would someone have to come up with a converter???

Lots of guys are using Seiko robot servos in Giant scale planes for the rudder. It delivers over 1KG of torque, but you need to drill some cooling holes to get reliable performance. These servos are used instead of a bunch of 8711's or 8611a's ganged together.

Also, Futaba has a new 9156 (I think) which has a lower torque rating, but is ROCK-SOLID and does not blow back. It has no slop and is quickly becoming the servo of choice for 3D and aerobatics in GS planes.

by your statement, "bunched together" ( or something along those lines), I gather you can daisy chain servo's together...

never thought of doing that.... hmmmmmmm more food for thought.

You can do that.

I am thinking that you are going to run into the problem with the amount of rotation in the servo. On a boat wont you need at least 180 degrees each way? An RC servo wont do that. I think you will better off looking at different classes of servos.

Multiplex makes industrial type servos.
I've seen them used on specially made remote operated transport vehicles that move radio-active isotope for Atomic Energy.

At this stage of your project it might be a good idea to look a little more into servo set ups and geometrys. It's not just about torque. There are servos with enough torque to move a school bus but the application doesn't fit.

checked the "rotation" this past weekend, actually it is more left and right approximately 3" from center. gonna need one heck of a control horn....

Servo City sells servos modified for use in robots.
http://www.servocity.com/html/robotzone_servos.html
Some are capable of continuous rotation, there are various gear boxes, etc.

thanks for the input... you guys have provided lots of useful information.

My question is................... why do you want to autopilot a 21' boat? and if your not thinking autopilot are you talking about remotely controlling a boat. Are you going to have a visual line of sight at all times?

good question, alot of times the wife and i fish at night, and navigating in the dark isn't much fun. hence the project. The idea/thought process is use a GPS, Laptop and a Autopilot device to assist with the navigation. I realize that this doesn't fall under the "RC" hobby, but i thought that where better to get help/information than here. You guys and gals are so full of ideas and information.