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The truth about servos

Old 12-16-2020, 09:08 AM
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jvaliensi
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Default The truth about servos

Which 15mm wide mini servos do you have the best luck with?
MKS 747 seems to be the gold standard. The ones I've used have been great.
I have a set of Promodeler 355's and they have been good so far. I thought they were the best, but my last conversation with John left me wondering.
I have used Savox's in RC cars with great success, but their airplane versions have not been great - I have a set of sailplane wing servos that didn't last a season and a set of micro servos in an electric 3D job that went bad fast, too. I wonder if their 15mm are any good.
Futaba high end servos seem to be awesome but tend to be ultra expensive.
I use KST in sailplanes and have really good luck with them. But never tried any as big as 15mm.

I'm paranoid that a single servo can cost me an entire airplane.
Old 12-16-2020, 09:19 AM
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I like the JR DS3421 sized servos -

Dee Force has their new version, the 3411,

https://www.deeforce.net/product-pag...1-programmable

Old 12-16-2020, 10:21 AM
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I ran Savox 1260ís in my T1 Mini for the last two years and they were great. Iíd buy the 1261ís today.

I also just got my first set of Savox 2290ís for a giant scale 3D plane and out of the box they are really impressive. Iíve moved to almost 100% Savox over the last couple years.
Old 12-16-2020, 11:39 AM
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I never had a servo Problem within the last 6 years. I fly the following servos:

Futaba S3150
Graupner DES 707 BB MG
Hitec 5645 MG
KST X10
KST BLS825
KST DS 589

I think servos are pretty reliable nowadays. Always check them thoroughly before installing. And to give them a nice working life, program (I fly JETI) servo limit properly and take good care of servo arm to control horn ratio. Then they work less for more power.

Old 12-16-2020, 02:22 PM
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Mks 747....
Old 12-16-2020, 08:50 PM
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MKS and Pro modeler, Savox OK but I have had 2 SG1256TG go all squeely on me and almost seized up, weirdest thing ever.

Am
Old 12-16-2020, 08:58 PM
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I just installed my first 2290ís tonight and so far Iím impressed, canít wait to fly them!
Old 12-17-2020, 05:34 AM
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I use A123 batteries in most jets. In those I use MKS DS1220 LiFe servos. They have more power (400+ oz @ 6.6v) than JR 8411s and work great. Inexpensive also. In my HV birds I use MKS 777A+.
Old 12-17-2020, 06:06 AM
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Dansy
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Originally Posted by tp777fo View Post
I use A123 batteries in most jets. In those I use MKS DS1220 LiFe servos. They have more power (400+ oz @ 6.6v) than JR 8411s and work great. Inexpensive also. In my HV birds I use MKS 777A+.

Pretty sure none of those are mini (midi) servoís
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Old 12-17-2020, 06:32 AM
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Rtfq
Old 12-17-2020, 06:35 AM
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Dansy
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Originally Posted by tp777fo View Post
Rtfq
Heís asking about 15mm servo as far as I can read 😂
Old 12-17-2020, 07:21 AM
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jvaliensi
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Yep, 15mm servos are a buggers. 20mm wide ones are easy to get in brushless with strong torque for a reasonable cost.
12mm & 13mm are easier to find too.
I don't think Hitec makes a 15mm and Futaba only has one model with 15mm wide.
I never had a JR servo, and I'm not sure the new JR is the same as the original JR.
I wish I could feel positive with Savox, but my experience with their small models has not been good.

I think I'll stick with MKS 747 & 747R or Promodeler 355's.
Old 12-17-2020, 08:30 AM
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For once I agree with Dansy.
Powerbox sells the 747.

These guys are no fools , after all they bought Weatronics, so if THEY sell them they HAVE to be good.
Old 12-17-2020, 04:00 PM
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Originally Posted by David Gladwin View Post
For once I agree with Dansy.
Powerbox sells the 747.

These guys are no fools , after all they bought Weatronics, so if THEY sell them they HAVE to be good.
Humm as usual I donít agree with you, but them anywhere but PoweBox 😂
Old 12-18-2020, 05:06 AM
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Another pointless, negative, misspelt, comment ( PowerBox name is the same in French and English. ( I presume by but you mean buy )
but who are YOU to suggest not to buy from PowerBox ?

I have no commercial connection with PB BUT I have used their products for many years and found them to be of the highest quality.

They also run a business with the highest ethics, and customer support, unlike some in this hobby.

They are now the European distributors of MKS servos, so if they put their name behind them they must be absolutely certain of their quality.

With the demise of JR,((a,though I have moved to Ditex 2612s and Futaba HPS A700 recently) I am looking for a new servo spec.for general use.

If PowerBox endorses MKS thats good enough for me.

Last edited by David Gladwin; 12-18-2020 at 06:36 AM.
Old 12-18-2020, 05:09 AM
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Dansy
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Originally Posted by David Gladwin View Post
Another pointless, negative, misspelt, comment ( PowerBox name is the same in French and English. ( I presume by but you mean buy )
but who are YOU to suggest not to buy from PowerBox ?

I have no commercial connection with PB BUT I have used their products for many years and found them to be of the highest quality.

They also run a business with the highest ethics, and customer support, unlike some in this hobby.

They are now the European distributors of MKS servos, so if they put their name behind them they must be absolutely certain of their quality.

With the demise of JR,((a,though I have moved to Ditex 2612s and Futaba HOS a 700 recently) I am looking for a new servo spec.

If PowerBox endorses MKS thats good enough for me.
Ahah your way too easy 😂 go have a tea....

He’s in the USA....PowerBox America to my knowledge doesn’t sell MKS servo.....but plenty dealers do

Last edited by Dansy; 12-18-2020 at 05:13 AM.
Old 12-18-2020, 05:19 AM
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Mks
Old 12-18-2020, 06:16 AM
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jvaliensi
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There are other brands:
Accutorq 220SG Mini HV servos. I thought I read somewhere that these are made by KST?

KST X15-908 HV Mini servo. I have used the X12, X10 and X08's from KST with good success.

Kingmax has a 15mm sevo under $30, if you can find it in stock. CLS2875H

Bluebird has a few 15mm servos, the BMS-A921 has 10kg torque and is under $50. I'm trying Bluebird for the first time in a small glider and so far they seem very smooth and quiet.
Old 12-19-2020, 06:08 PM
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i was a diehard jr servo guy, i switched to futaba, they are pretty nice. certainly as good as jr was. xbus is a bonus but they are completely programmable even without using xbus. i would say they are maybe 15% over priced. futaba brand premium i guess

i use BLS173SV as a standard aileron servo for pretty much everything. easier spares. i think it is 14 mm
Old 12-20-2020, 11:16 AM
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Hitec, cause they make them for all!
Old 12-24-2020, 01:08 PM
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jvaliensi
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I did a little testing using my ToolKitRC servo tester. It reads out the current the servo is using in real time.
I clamped the servo to my bench and suspended 675g from a 20mm servo arm. I recorded the idle amps with no load, the amps to lift the weight and the idle current with the weight attached.

MKS 747: idle 28mA, idle w/ load 200mA, moving 675mA

Futaba BLS173SV: idle 26mA, idle w/ load 26mA or 300mA*, moving 960mA

Savox SV1261MG: idle 10mA, idle w/ load 310mA or 10mA*, moving 1,700mA

Promodler DS100DV; Idle 10mA, idle w/ load 531mA or 10mA*, moving 950mA

The Futaba would go to idle current with the load attached. The Savox and Promodler will too, but I had to play with the output signal. The MKS would not go to idle current with a load. This may be due to how the control algorithm is written between different brands.
It leads me to think the MKS will use more energy over time.

The Savox & MKS are rated at the same torque, but the Savox drew more current to move the same load.

I like the way the Futaba went to idle amps and quit buzzing with the load attached. I'm not sure they are strong enough for flaps on a 14lbs jet.
Old 12-24-2020, 06:37 PM
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Dansy
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Originally Posted by jvaliensi View Post
I did a little testing using my ToolKitRC servo tester. It reads out the current the servo is using in real time.
I clamped the servo to my bench and suspended 675g from a 20mm servo arm. I recorded the idle amps with no load, the amps to lift the weight and the idle current with the weight attached.

MKS 747: idle 28mA, idle w/ load 200mA, moving 675mA

Futaba BLS173SV: idle 26mA, idle w/ load 26mA or 300mA*, moving 960mA

Savox SV1261MG: idle 10mA, idle w/ load 310mA or 10mA*, moving 1,700mA

Promodler DS100DV; Idle 10mA, idle w/ load 531mA or 10mA*, moving 950mA

The Futaba would go to idle current with the load attached. The Savox and Promodler will too, but I had to play with the output signal. The MKS would not go to idle current with a load. This may be due to how the control algorithm is written between different brands.
It leads me to think the MKS will use more energy over time.

The Savox & MKS are rated at the same torque, but the Savox drew more current to move the same load.

I like the way the Futaba went to idle amps and quit buzzing with the load attached. I'm not sure they are strong enough for flaps on a 14lbs jet.
ĎYou sure like to complicate thingís...personally I just use install them....canít drain my battery every day so itís all good 😌 😂
Old 12-27-2020, 11:35 AM
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Doug Cronkhite
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Originally Posted by David Gladwin View Post

With the demise of JR,((a,though I have moved to Ditex 2612s and Futaba HPS A700 recently) I am looking for a new servo spec.for general use.
Demise of JR? What are you talking about, David? JR is very much alive and well.
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Old 12-27-2020, 02:43 PM
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Ad Clark
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JR makes GREAT SERVOS .
Old 12-27-2020, 04:28 PM
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Dansy
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Originally Posted by Ad Clark View Post
JR makes GREAT SERVOS .
ĎThe last one I got from JR USA crash my plane those were the MP series...just junk..

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