Originally Posted by LoneWolfRC

I am looking for servos for my first gas/large plane.

Thanks for posting this.

In the table, I don't understand why it has two weights listed (2.9 and 4.0 oz.).

Also, what does "MK First gear mean"?

What is the width of that servo arm?

This looks like a cool servo.

MK is metal pinion karbonite main gear.

Originally Posted by Mike Mayberry

RF noise with metal to metal contact to an electric motor.

Mike.

Thanks, I always wonder about that but it makes total sense.

It doesn't make sense to me. I'm not saying it's wrong. I just don't understand. But what makes me skeptical isn't Mike Mayberry's fault: I've seen all sorts of crazy theories regarding RF spewed by engineers who should know better (and I might have even spewed a few of them myself.)

Originally Posted by LoneWolfRC

It doesn't make sense to me. I'm not saying it's wrong. I just don't understand. But what makes me skeptical isn't Mike Mayberry's fault: I've seen all sorts of crazy theories regarding RF spewed by engineers who should know better (and I might have even spewed a few of them myself.)

Start reading...there's ton more where this came from...

http://www.radio-electronics.com/inf...y-rf-noise.php

So this is a HS-7954SH High Voltage Ultra Torque
with a Seacraft top case?

spec wise, it looks that way.. I'm out though

Originally Posted by Smacka

Start reading...there's ton more where this came from...

http://www.radio-electronics.com/inf...y-rf-noise.php

Thanks for the link. I just went to the page, have studied the topics presented there in the past, didn't find anything pertinent to metal gear on metal gear noise. Most of the topics presented in the link were dealing with phenomenon in semiconductors, not motors.

In the interest of full disclosure, I am fairly competent when it comes to RF, noise, and have on multiple occasions had my designs get through emissions (unintentional radiator) testing with first past success thanks to my technical understanding of noise and RF energy--indeed, I'm batting 1000 this past decade, including some intentional radiator (RF) designs...but I don't recall ever studying anything regarding metal on metal gears, when one of the gears is connected to a motor, leading to RF noise.

But that's possibly because I don't do electromechanical devices like a servo or even anything with motor control. I'm usually working in the 100 MHz to 2.5 GHz range.

So I am genuinely interested in this, partly for more knowledge if it's true, and possibly to learn that this is a plausible sounding but otherwise untrue explanation that is nevertheless repeated.

A more specific explanation would be most appreciated.

Originally Posted by LoneWolfRC

Thanks for the link. I just went to the page, have studied the topics presented there in the past, didn't find anything pertinent to metal gear on metal gear noise. Most of the topics presented in the link were dealing with phenomenon in semiconductors, not motors.

In the interest of full disclosure, I am fairly competent when it comes to RF, noise, and have on multiple occasions had my designs get through emissions (unintentional radiator) testing with first past success thanks to my technical understanding of noise and RF energy--indeed, I'm batting 1000 this past decade, including some intentional radiator (RF) designs...but I don't recall ever studying anything regarding metal on metal gears, when one of the gears is connected to a motor, leading to RF noise.

But that's possibly because I don't do electromechanical devices like a servo or even anything with motor control. I'm usually working in the 100 MHz to 2.5 GHz range.

So I am genuinely interested in this, partly for more knowledge if it's true, and possibly to learn that this is a plausible sounding but otherwise untrue explanation that is nevertheless repeated.

A more specific explanation would be most appreciated.

Yeah, you were fairly vague in your post, as it sounded like your position was one of "I refuse to believe in God until he shows up right in front of me", which lead me to believe you had no prior knowledge of fundamental electronics.

With respect to your comment requesting a better explanation, I still say "google". When I need information, I go get it (not meant condescending) because rarely is their factual information passed along in an open forum.

I do believe you are on the right track with respect to electromechanical discussion.

One last note, I went to Joe Nall two years ago. A person had contructed a servo test box to prove RF affected servo operation. It was quite informative. I watched as he could turn on and off the effects of RF with a particular device he was testing (a receiver). He had an all metal gear train and demonstrated that the servo jittered to beat the band as he exercised the receiver with his radio. He switched out one of the gears with a "non-conductive" one, and the problem went away. It seemed as though the all metal gear train was trying to act like an antenna of sorts (??).

Have fun!

It comes down to electricly floating the servo motor shaft on one end, easiest end to do this is on the main drive external to the servo, shaft ground currents can infract upon electronics in very perculiar ways -

Originally Posted by Alkaline

Meh,

whatever happened to the brushless servos?

It would appear the hitec engineers in Tiwan are not wanting to make the same mistakes they did with the 79XX series...
Build dif. designed boards, or keep the same design and make sure the motors don't cause the dreaded...rudder "wagle"....

Originally Posted by JoeAirPort

Mike M, can you explain why the first gear is always some sort of plastic on your MG servos? Makes no sense. Why not all metal?

Metal to Metal would be an issue do to RF noise to the electric motor, think about your engine same thing..

Originally Posted by off2fly

Can Hitec be trusted?

Did not understand this but feel the need to reply. I have been flying with Mike and the TEAM with no issues for a while now again with NO issue at all. Hitec in itself is a cutting edge company with Ideas that the others seem to follow, and take the lead from so if they trust the ideas why not everyone else. I have flown other brands and they are all good. However Mike and Hitec LEAD the way and are always stepping forward. I think that is were you want to be. Trust has never been an issue with Mike and or the HITEC brand. Mike always is out to take care of the customers, and the TEAM first rate person and FIRST RATE product.

Again this is my opinion and my experience with Mike, and HITEC product. I am glad to fly and be a part of this TEAM.

Originally Posted by crackedup

Metal to Metal would be an issue do to RF noise to the electric motor, think about your engine same thing..

Should have read a couple post further Mike answered.

Sorry about that Mike.

Originally Posted by LoneWolfRC

It doesn't make sense to me. I'm not saying it's wrong. I just don't understand. But what makes me skeptical isn't Mike Mayberry's fault: I've seen all sorts of crazy theories regarding RF spewed by engineers who should know better (and I might have even spewed a few of them myself.)

The original 945MG had all metal gears with "special grease" that was supposed to resolve the issue but as the grease wore off the servo would start to twitch. We then developed the MP (Metal/Plastic) gear. Then came the M/K (Metal/Karbonite) and on the new soon to be released brushless servos we will have the outer portion of the Karbonite sandwiched with a ring of aluminum around the outside edge that touches the motor pinion. This increases the strength of the gear even further for the 500in/oz+ servo but still leaving the buffer zone.

Originally Posted by Jkoch713

So this is a HS-7954SH High Voltage Ultra Torque
with a Seacraft top case?

Yes.

Mike.

Now I am tempted to tear into a Futaba BLS-157HV and see how they do it. It is as close to a perfect servo as I have ever had, it has 500+ oz-in, and is brushless. Hopefully Hitec bought a few and took some notes. I get them from the LHS for $155 each.