Hi again Philippe,After checking out the videos on OpenCockpits site I would seem to be wrong, they all appear to show a marked amount of jerkyness to the movements of the servo. Maybe Ferdie will pop-up and comment.The Porcupineaka Simon Webbwww.desktopflying.co.ukVery slowely putting together a generic twin desktop unit.

It should be possible to increase the number of turns of a RC servo by hacking it: replacing the standard feedback potmeter with a 10-turn potmeter. Just make sure there is no limiting notch on the gears. The servo gain may need to be tweaked a little as well to get the response back in line. It will take some tinkering, but I did this succesfully in the past to build a sail winch for my RC sail boat. Not all servo IC's are well known, but a seach on google on the IC type number should give some info. Hope this helps, Roland

Philippe,RC servos have a "dead zone" in the internal servo feedback path. This means that the input muct change some small amount before the servo electronics will activate the motor to turn the servo output shaft. If the dead zone were not there, the motor would be continually moving back and forth using power and wearing itself out. This is a result of electrical noise in the servo electronics, to a small extent, but mostly due to mechancial play (backlash) in the gearing. The amount of dead zone will vary somewhat by servo model. I tested an inexpensive standard size servo from Tower Hobbies by taping a long extension on the control horn, and very slowly changing the width of the servo control pulse. The servo very clearly moved in small, discreet steps. I counted about 250 steps for the 180 degree movement of the servo.I have read in advertisements for servos of some much more expensive models with reduced dead zones. However, I don't recall specifics.If you use a 1:2 gear ratio on the output of a standard servo to extend the rotation from 180 degrees to 360 degrees, you will still only have 250 steps. The step size will be almost 1.5 degrees each.You can get smoother movement by using a 400 step per revolution stepping motor. This gives you a 0.9 degree step. If you half step the motor, you get a 0.45 degree step. You can further reduce the step size by micro stepping the motor using chips from Allegro, and/or gearing down the output of the motor.Mikewww.mikesflightdeck.comwww.mikesflightdeckbooks.com