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Old 09-29-2016, 03:30 PM
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All Metal Gear Servos for Giant Scale

Hi All,

The purpose of my post is to learn Pro's / Con's of all metal geared Servos for 35-40% aircraft,

Backdrop: I fly an Aeroworks 150CC YAK with a DA170 on pipes and all Servos on control surfaces are the JR 8711HV's which were advertised as "metal Gears".
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I am running 3 servos per wing. The Aeroworks manual specified metal gear servos. Last weekend the right wing outboard servo appeared stripped, and after inspection at home it turns out it was. The gear that stripped is JR part: JRPSGB4 and it turns out the Ring portion of this Ring/Pinion gear is not metal, but looks to be karbonite. It engages the motor drive pinion gear. This karbonite ring gear was stripped. The rest of the gears are metal. The plane has never been crashed or abused.

I read on ServoCity's website that metal gears wear quicker than nylon or karbonite gears, and result in some play. However this karbonite gear seems to be the weak link and perhaps is designed to be so. I am disappointed though because I felt I was complying with the Aeroworks spec when using these servos that JR advertised as all metal gears.

Now I am considering replacing these with truly All Metal Gear servos and wonder what others experience has been with all metal gear servos.

I am considering using PDRS420v4 servos from audacitymodels.com They truly are all metal gears, and the motor is brushless.
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My specific interest is in other's experience with All Metal Geared servos.

Thanks
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Old 09-29-2016, 03:41 PM
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We have tried many many different brands and makes of servos searching for the best on the market. The problem you discribe is exactly what we experienced as well with the same servo. We now settled with a brand which truly uses all metal gears and are extremely happy!! ...by far the best we have ever used
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Old 09-29-2016, 03:49 PM
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Quote:
Originally Posted by jdracing3 View Post
We have tried many many different brands and makes of servos searching for the best on the market. The problem you discribe is exactly what we experienced as well with the same servo. We now settled with a brand which truly uses all metal gears and are extremely happy!! ...by far the best we have ever used
What Brand, and manufacturer Part #, Please?
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Old 09-29-2016, 04:14 PM
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Old 09-29-2016, 05:34 PM
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love the pro modeler servos! they are my go to now!
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Old 09-29-2016, 08:19 PM
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Savox 1270, Savox 2270, Savox 2290

All are what you describe...All metal

Brian
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Old 09-29-2016, 08:55 PM
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Savox and MKS are what i use.. Even HiTec 7955's on HV are a good choice.. Every JR i ever ended up with had play in it and jittered like crazy at idle... If im gonna pay 150 bux for a servo it should have all metal gears!! My go to servo is the MKS 777's.. Over 500 oz. of torque uses a futaba spline and is pretty fast @0.11 on 7.4 unregulated.. And im pretty sure the gears are helical cut so they are really smooth and quite.. For just over a $100 a piece i like em.. Hope this helps..
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Old 09-29-2016, 09:08 PM
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Quote:
Originally Posted by SMOKINMAC View Post
What Brand, and manufacturer Part #, Please?
Here's a link. You can pick what best fits your requirements

http://www.mksservosusa.com/
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Old 09-29-2016, 10:21 PM
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Standard practise in most manufactures to have the first gear as karbonite, sacrificial gear in the case of hitting the ground etc… MKS, Futaba, Hitec all good choices.

From back in 2012 Geetarjoe wrote “MK means "metal/Karbonite" if im not mistaken. its a karbonite main gear with a metal pinion. works well as the first gear doesnt have a lot of stress on it. the output gear has the most torsional load, with the load on the rest going down exponentially. the gear mesh eats up a lot of stress and does a lot to distribute the load over a large area. the karbonite gear allows for a sacrificial gear that can be easily replaced and is inexpensive compared to a motor or an output gear.
the location of the Karbonite gear in first position doesnt sacrifice load carrying capability.”

and from Futaba USA

All metal gear" servos will have some type of nylon or or composite first gear. The first gear needs to be something other than metal to prevent radio interference. If all of the gears were exactly the same, severe radio glitching could be a problem.
Also having one nylon gear presents less points of failure, guaranteeing that the metal gears do not strip.

This is true of not only Futaba, but if you will check out other servos, you will see that almost all RC suppliers of servos, offer a nylon 1st gear in their metal gear servos.

You might also want to check out some RC forums for information on servo performance, as this will help you understand more of the basics of RC.

Sincerely,
Krysta
Product Development & Support Specialist
Futaba Service Center USA
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Old 09-30-2016, 04:58 AM
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Quote:
Originally Posted by SMOKINMAC View Post
Hi All,

The purpose of my post is to learn Pro's / Con's of all metal geared Servos for 35-40% aircraft,

Backdrop: I fly an Aeroworks 150CC YAK with a DA170 on pipes and all Servos on control surfaces are the JR 8711HV's which were advertised as "metal Gears".
Attachment 970314 Attachment 970315
I am running 3 servos per wing. The Aeroworks manual specified metal gear servos. Last weekend the right wing outboard servo appeared stripped, and after inspection at home it turns out it was. The gear that stripped is JR part: JRPSGB4 and it turns out the Ring portion of this Ring/Pinion gear is not metal, but looks to be karbonite. It engages the motor drive pinion gear. This karbonite ring gear was stripped. The rest of the gears are metal. The plane has never been crashed or abused.

I read on ServoCity's website that metal gears wear quicker than nylon or karbonite gears, and result in some play. However this karbonite gear seems to be the weak link and perhaps is designed to be so. I am disappointed though because I felt I was complying with the Aeroworks spec when using these servos that JR advertised as all metal gears.

Now I am considering replacing these with truly All Metal Gear servos and wonder what others experience has been with all metal gear servos.

I am considering using PDRS420v4 servos from audacitymodels.com They truly are all metal gears, and the motor is brushless.
Attachment 970313

My specific interest is in other's experience with All Metal Geared servos.

Thanks
These are also made in America... by a small business man... nothing like helping out the little guy... people are scared of them... I was too at first for $79 for 420ox in of torque... after my first set, I was hooked... John Beech is the owner the phone number listed on www.audacitymodels.com is his cell number... the best customer service I have ever dealt with! He is a stand up guy!
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Old 09-30-2016, 06:18 AM
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Quote:
Originally Posted by Carruthers43 View Post
These are also made in America... by a small business man... nothing like helping out the little guy... people are scared of them... I was too at first for $79 for 420ox in of torque... after my first set, I was hooked... John Beech is the owner the phone number listed on www.audacitymodels.com is his cell number... the best customer service I have ever dealt with! He is a stand up guy!
I am so glad to see this. This country is losing out on so much now days since businesses basically have no choice but to go abroad. Someone needs to change this and bring business back. Businesses are so strapped by government bog that cannot hardly breath.

Sorry for the rant, back to the servo discussion

BTW, I run Savox and Hitec and no issues. I do like the thought of getting some promodelers to help them be more successful here in the USA.
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Old 09-30-2016, 07:41 AM
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In my experience, most servo torque claims are optimistic (to be polite). The Savox 2270, 2231, and Futaba BLS-157's are very close to the advertised claims. However, neither of them have any customer service, so when they get old and sloppy (especially the Savox 2231) you basically toss them.
Some Hitec servos are pretty close to advertised specs, especially the smaller torque models like the 5665 and 5685, but the 7954/7955 are not very close to the claims. However, Hitec has excellent CS and most of the time they repair it or replace them at no cost.
I have no data on the MKS personally, but a friend has tested them and they were close to the claims, but I have no idea what their repair/CS is.
And in regards to steel versus titanium gears, the only advantage to Ti is it is lighter. Ti galls, and it not really a good choice for gears or any sliding surface.
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Old 09-30-2016, 09:41 AM
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To All who have replied, I just wanted to jump back in and say thank you.
Some of this information is very informative, again thanks.
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Old 09-30-2016, 09:52 AM
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Quote:
Originally Posted by rcflip View Post
Standard practise in most manufactures to have the first gear as karbonite, sacrificial gear in the case of hitting the ground etc… MKS, Futaba, Hitec all good choices.




and from Futaba USA

All metal gear" servos will have some type of nylon or or composite first gear. The first gear needs to be something other than metal to prevent radio interference. If all of the gears were exactly the same, severe radio glitching could be a problem.
Also having one nylon gear presents less points of failure, guaranteeing that the metal gears do not strip.

This is true of not only Futaba, but if you will check out other servos, you will see that almost all RC suppliers of servos, offer a nylon 1st gear in their metal gear servos.

I can see the logic in the nylon or karbonite first gear, but I too experienced stripping of that gear on a set of Ti-geared Hyperion mini servos. They had very good torque specs(130oz) for a mini, so I tried them in a 60" EF plane. Stripped the rudder servo in less than 10 flights; was quite disappointed, as the cheap Spektrum minis I'd been using had never done that. Not sure if the "sacrificial" gear is a good idea or not...
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Old 09-30-2016, 10:09 AM
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Quote:
Originally Posted by wyo69cowboy View Post
I can see the logic in the nylon or karbonite first gear, but I too experienced stripping of that gear on a set of Ti-geared Hyperion mini servos. They had very good torque specs(130oz) for a mini, so I tried them in a 60" EF plane. Stripped the rudder servo in less than 10 flights; was quite disappointed, as the cheap Spektrum minis I'd been using had never done that. Not sure if the "sacrificial" gear is a good idea or not...


Just a heads-up, MOST of the MKS servo line uses full metal gears.


http://www.mksservosusa.com/home.php...ction=0&page=1
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