Servos - Futaba, Hitec, Airtronics, JR, and Kraft

ctdahle

From my model airplane experience, I am aware that these various brands of servos are not interchangeable. There are differences in the pinout order as well as connector style. The Kraft servos use an entirely different pulse timing than the others. Futaba (whom, I believe, manufacture the Parallax servos) differ from Airtronics, JR, and Hitec because of "pulse shift".

I am wondering if anyone here knows of, or has created a chart or table that indicates the differences and breaks down the wiring and programming differences necessary to program these various servos and use them with the BS2.

Phil Pilgrim (PhiPi)

I thought Kraft just made Velveeta. I didn't know they were into servos, too!

-Phil

erco

Mmmmmmmm, my stomach is howlin' for Kraft Servo & Cheese...

W9GFO

My first radio was Kraft 4 ch.

JR, Futaba and Hitec all work the same. Futaba is slightly different in that they consider 'center' to be 1.520 milliseconds and the others use 1.500.

Not sure about airtronics or multiplex, I'm sure a quick Google search would turn up the answer.

Rich H

W9GFO

And yes, the Parallax servos are made by Futaba.

Rich H

ctdahle

W9GFO wrote: »

...I'm sure a quick Google search would turn up the answer.

I thought so too Rich...admittedly I don't always write the best queries, but I didn't have any luck.

I thought it might be nice to use these big old Kraft KPS 12s as continuous rotation servos. They have these really beefy gears and motors.

Then too, I have lots of Airtronics old style and Z types and a handfull of Hitec HS-81s, but no Futabas.

I'm reluctant to just plug them in and try them. I'm not worried about the servos, but I'm skittish about plugging anything into the servo blocks if there is any potential to damage my new BOE.

I vaguely recall something about having to re-arrange the leads on Hitec servos to plug them into a Futaba receiver, but I can't seem to find my notes on the issue and came up dry when I searched the RCU archives too.

Cheers,

Chris

ctdahle

OK, I found this chart:

http://fatlion.com/sailplanes/servochart.html

But I'm still skittish about the pinout order...probably I just need to RTFM.

W9GFO

I searched for "Airtronics servo wiring" and found this page.

Airtronics has the Positive and Ground wires reversed in their connectors. The others are the same.

Rich H

ctdahle

Thanks Rich, that nails it. I now see that the connection difficulties I was aware of were more mechanical than electronic. Not an issue with the BOE once I understood where the signal connection needed to be made. As a bonus, I discovered that I can simply rearrange the pins on my old style Airtronics servos in order to make them compatible with my "new" (only 13 years old) radio gear.

I am able to move all of my servos except the KRAFTs; with them, I remain unsure about how to set the PULSOUT duration and how long a pause is needed. Besides, the leads are red, white and yellow, so I'm not sure which lead is which.

ERCO and Phil, especially Phil--KRAFT SYSTEMS...named for, _Phil_ Kraft was one of the pioneers of radio control and played a big role in designing the system of servo control by sending timed pulses.

KRAFT Systems was famous for its "gold box" RC transmitters that were about the color of ....Velveeta!!! So enjoy a Spam, Velveeta, & Servo. Make it open faced on Wonder Bread. Pop it under the broiler for 3 minutes. Serve hot and wash it down with a cold glass of DeoxIT.