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What the newest cheap servo hotness?

I've been thinking about my earlier comment about high-pressure grease. It was mostly made in jest, but I'm thinking that could be a thing. Similar problems result if you use the wrong grease in an automotive axle/bearing or oil in a diff/transmission.

I'd recommend people with 46kg JX's clean the stock goo off any try some good synthetic H-P or moly grease (not lithium grease).


durok said:
Generally speaking, titanium is a harder metal than aluminum and is nearly as hard as heat-treated alloy steels.
Click to expand...

I hate to really nitpick but too many people repeat this incorrect info. It bugs me to death.

Titanium is only good when it comes to weight or reactivity. It can be about as strong as steel but lighter, 5% weaker & 45% lighter for typical alloys. If the size of the part is unrestricted, aluminum/magnesium/beryllium can all be lighter & stronger. For a gear where dimensions will be the same & high-performance alloys of both are used, the steel will ALWAYS be stronger - and more ductile, shock resistant, wear resistant, harder, etc. Even so, Inconel makes them ALL look silly. But I digress.


holycaveman said:
Our servos are advertised "dynamic" torque. Not static torque from a fish scale. As was pointed out in the video. I am very surprised they were that high on pure static. Definitely something to be excited about.
Click to expand...

Do you mind explaining this "dynamic" torque, because my BS meter appears to be pegged. Your webpage literally says "Stall Torque (11.1v): 527oz". Stall torque is defined literally as "the torque produced by a mechanical device whose output rotational speed is zero". In the vid at 12v it shows 484.9oz using the outside hole on that arm (1" from shaft centerline) at 90 degrees when it stalls, or 8% short.

For reference, the same test jig recorded 550oz/in for the Turnigy 959v1 at 5.7v & 498oz/in for the v2 while the G13 needed 15.8v to hit 566.7oz/in. The Achilles heel of the cheap servos seem to be the gears, so I really hope to never hear of a G13 gear failure - or at the very least zero-hassle repairs of any gear probs.
 
Last edited:
Hydrocarbon92 said:
I've been thinking about my earlier comment about high-pressure grease. It was mostly made in jest, but I'm thinking that could be a thing. Similar problems result if you use the wrong grease in an automotive axle/bearing or oil in a diff/transmission.

I'd recommend people with 46kg JX's clean the stock goo off any try some good synthetic H-P or moly grease (not lithium grease).




I hate to really nitpick but too many people repeat this incorrect info. It bugs me to death.

Titanium is only good when it comes to weight or reactivity. It can be about as strong as steel but lighter, 5% weaker & 45% lighter for typical alloys. If the size of the part is unrestricted, aluminum/magnesium/beryllium can all be lighter & stronger. For a gear where dimensions will be the same & high-performance alloys of both are used, the steel will ALWAYS be stronger - and more ductile, shock resistant, wear resistant, harder, etc. Even so, Inconel makes them ALL look silly. But I digress.




Do you mind explaining this "dynamic" torque, because my BS meter appears to be pegged. Your webpage literally says "Stall Torque (11.1v): 527oz". Stall torque is defined literally as "the torque produced by a mechanical device whose output rotational speed is zero". In the vid at 12v it shows 484.9oz using the outside hole on that arm (1" from shaft centerline) at 90 degrees when it stalls, or 8% short.

For reference, the same test jig recorded 550oz/in for the Turnigy 959v1 at 5.7v & 498oz/in for the v2 while the G13 needed 15.8v to hit 566.7oz/in. The Achilles heel of the cheap servos seem to be the gears, so I really hope to never hear of a G13 gear failure - or at the very least zero-hassle repairs of any gear probs.
Click to expand...


This times 100. Much more detailed statement explaining what I meant by the servo under performing.
 
Hydrocarbon92 said:
I've been thinking about my earlier comment about high-pressure grease. It was mostly made in jest, but I'm thinking that could be a thing. Similar problems result if you use the wrong grease in an automotive axle/bearing or oil in a diff/transmission.

I'd recommend people with 46kg JX's clean the stock goo off any try some good synthetic H-P or moly grease (not lithium grease).




I hate to really nitpick but too many people repeat this incorrect info. It bugs me to death.

Titanium is only good when it comes to weight or reactivity. It can be about as strong as steel but lighter, 5% weaker & 45% lighter for typical alloys. If the size of the part is unrestricted, aluminum/magnesium/beryllium can all be lighter & stronger. For a gear where dimensions will be the same & high-performance alloys of both are used, the steel will ALWAYS be stronger - and more ductile, shock resistant, wear resistant, harder, etc. Even so, Inconel makes them ALL look silly. But I digress.




Do you mind explaining this "dynamic" torque, because my BS meter appears to be pegged. Your webpage literally says "Stall Torque (11.1v): 527oz". Stall torque is defined literally as "the torque produced by a mechanical device whose output rotational speed is zero". In the vid at 12v it shows 484.9oz using the outside hole on that arm (1" from shaft centerline) at 90 degrees when it stalls, or 8% short.

For reference, the same test jig recorded 550oz/in for the Turnigy 959v1 at 5.7v & 498oz/in for the v2 while the G13 needed 15.8v to hit 566.7oz/in. The Achilles heel of the cheap servos seem to be the gears, so I really hope to never hear of a G13 gear failure - or at the very least zero-hassle repairs of any gear probs.
Click to expand...

Dynamic torque is measured with a digital device that clamps to the top of the servo. It is very accurate and is often used on rotational loads. It calculates the peak torque with speed that the servo produces.

The difference between our servo and the others is that ours runs very cool. You can come to a stall 20 times and hold it running 4s and the servos do not get hot. Unlike many others. The hotter the servo gets the more power it looses. Ours stay consistent.

As far as " Achilles heel of the cheep servos". you must believe all servos are cheap with that statement. Because anyone who has any substantial experience using servos knows that no gear set in indestructible.
We are very confident with the way our servos are designed. And our customers back that up.
 
So when you say "dynamic torque", you mean the amount of torque the servo can transmit while the motor/gears/hub are rotating? I guess that's good to know, but why would it be different from the amount of torque the servo can transmit when stalled? The servo is powered by an electric motor, so the torque should be the same regardless of whether the motor is able to rotate or not.
 
That seems to spit in the face of the fact that motors have optimal operating temperatures, because it isn’t as simple as cool == better...
 
fyrstormer said:
So when you say "dynamic torque", you mean the amount of torque the servo can transmit while the motor/gears/hub are rotating? I guess that's good to know, but why would it be different from the amount of torque the servo can transmit when stalled? The servo is powered by an electric motor, so the torque should be the same regardless of whether the motor is able to rotate or not.
Click to expand...

A dynamic torque measurement involves an acceleration factor. Which usually will read slightly higher than a static torque measurement of the same servo. A lot of manufacturers use dynamic torque ratings. Tekin and Protek being two of them.
 
Last edited:
holycaveman said:
Dynamic torque is measured with a digital device that clamps to the top of the servo. It is very accurate and is often used on rotational loads. It calculates the peak torque with speed that the servo produces.
Click to expand...

This article seems to explain it, but it's flat-out stating that dynamic torque is different from static torque. The best description they use is measuring a multi-cyl IC engine at the crankshaft vs measuring at the wheels. Static torque is the average torque seen at the wheels while dynamic is the peak for each combustion event, usually called peak instantaneous torque. A Honda 2.4L will actually have a higher instantaneous torque than a Ferrari 3.6L v8, but we know which has more HP. Just recently SAE engine ratings have changed to reflect what's actually happening. In the 60's they used SAE Gross, which was with no accessories, no water pump, no flywheel - which lead to "gross" differences.

https://www.eetimes.com/document.asp?doc_id=1273988

In any case, your website only lists stall torque. It's also pointless to tell us dynamic torque but not stall torque when every other MFG does the opposite. Imagine if Ford measured how much force it takes to rip off the trailer hitch, then listed that as "tow rating".

I understand everything can break, but for 3-4 times the price I'd expect 3-4x less broken gears or replacements that are 3-4x cheaper. $18 for a gearset is 1/3 the price of an entire JX servo.
 
2mtech said:
Bummer...looks like the Promodelers are on b/o for awhile. Just because I decided to get one. :roll:
Click to expand...

I spoke with him a couple weeks ago, 3rd week of july is when they are getting a shipment of 470s in.
 
Hydrocarbon92 said:
This article seems to explain it, but it's flat-out stating that dynamic torque is different from static torque. The best description they use is measuring a multi-cyl IC engine at the crankshaft vs measuring at the wheels. Static torque is the average torque seen at the wheels while dynamic is the peak for each combustion event, usually called peak instantaneous torque. A Honda 2.4L will actually have a higher instantaneous torque than a Ferrari 3.6L v8, but we know which has more HP. Just recently SAE engine ratings have changed to reflect what's actually happening. In the 60's they used SAE Gross, which was with no accessories, no water pump, no flywheel - which lead to "gross" differences.

https://www.eetimes.com/document.asp?doc_id=1273988

In any case, your website only lists stall torque. It's also pointless to tell us dynamic torque but not stall torque when every other MFG does the opposite. Imagine if Ford measured how much force it takes to rip off the trailer hitch, then listed that as "tow rating".

I understand everything can break, but for 3-4 times the price I'd expect 3-4x less broken gears or replacements that are 3-4x cheaper. $18 for a gearset is 1/3 the price of an entire JX servo.
Click to expand...

Guys who run our servos will never run a turnigy. Our guys want support as well as a quality product. They want a compamy that if they have any issue they know they will get it taken care of in a couple of days not month's or in case of the cheap ones.........never. Those cheap servos are not even in the same ballpark. Our servos have the reputation of being one of the strongest servos on the market. And we stand behind them.
 
I understand your concern as far as static vs stall. And they way our website read could be a bit confusing. Regardless its one of the strongest on the market. And the way its designed it will keep pulling the max torque at a stall without failure.

All the best.
 
I ordered a ds3218 for $12.75 shipped from ebay this evening. That 15% off coupon was enough for me to stray from my equally cheap go-to mg958, mostly because it will be here in a few days, instead of a few weeks as when shipped from China. This will be replacing a Traxxas 2075 on a Slash with 2.2 Ripsaws, so more than doubling the torque, and a few hundredths of a second faster will both be appreciated.
 
TheLetterJ said:
I ordered a ds3218 for $12.75 shipped from ebay this evening. That 15% off coupon was enough for me to stray from my equally cheap go-to mg958, mostly because it will be here in a few days, instead of a few weeks as when shipped from China. This will be replacing a Traxxas 2075 on a Slash with 2.2 Ripsaws, so more than doubling the torque, and a few hundredths of a second faster will both be appreciated.
Click to expand...

You have a 2075 that hasnt burnt itself out yet? Lucky dog! Every 2075 ive had blew its fuse during normal 2s SCT use. 4 for 4.
 
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