Servos
 

Going to order the radio tonight (JR XS3 Pro) and had some servo questions. From what I've read it looks like its a digital system, that being said (if correct), whats the benefit of running a digital servo. I know transmission time is supposed to be reduced but is it really noticeable? Most of the digital servos seem to lack torque and speed. What I mean is the torquey servos (120+) seem to have transit times in the .13-16 sec area. I would prefer a servo around .10 (even less). I have found a couple but the torque is around 105-110, is that "good enough" or should I not bother with a digital? I'm looking at the JR Z8800S (105oz/.08sec). Its high torque brother is 188/.15sec.

Also, are the digital servos of other manufacturers completely compatible with other systems? Would an Airtronics digital servo work at 100% connected to a JR receiver?

RE: Servos
 

If you want the specs then you have to pay for them. But yes faster transition times can be told by the experienced hand. No pun intended. I mean that a faster servo even by 0.05 secs can mean the diference between a tight turn and a long loop.

RE: Servos
 

yes it will work fine. i run a futaba s9451 its .10 and fast and torque is 120oz .i just bought a airtronics 94360Z & this thing has 200oz of torque and at .07 sec thats damm great. and it has a heat sink head. just watch ebay they have some right now pretty cheap.

RE: Servos
 

Not quite what I was getting at Alex, I can feel the difference between the spec'd speeds on servo, what I was curious about was two servos with the same ratings, one being digital and the not. Digital doesnt effect the specs on the servo, but the rate of transmission from input on the radio to action on the servo is supposed to be increased.

I have no problems paying for speed, there is nothing worse than a slow whimpy servo.

Main question, is 105 good enough or should I look for more? I've found a few nice Airtronics servos as well (758 for instance), not affraid to pay for it. Both servos are priced about the same.

RE: Servos
 

Was pretty sure the 360 only had 125oz torque as well.

RE: Servos
 

ooops sorry here is the specs for the airtronics
Weight: 2.12 oz
Dimensions: 1.54 x 0.79 x 1.47
Volts@: 4.8 / 6.0
Torque: 100 / 125
Speed: 0.09 / 0.07
Motor: Coreless
Gear: M (Metal)
Bearing: 2

RE: Servos
 

The real advantage of digital is centering; ie.. transit time is measured at 60* of rotation under load, this means how fast the servo will rotate from full travel.
Digital servos will return to center faster and more accurately than non digital.
Torque is a different story...while 110-120 oz will steer your buggy fine, more torque (commonly found in faster servos)will result in less stress on the servo to do its job, thus the expensive servo will last longer under normal use.

RE: Servos
 

Digital servos were originally developed to me more precise than an analog servo for large scale pattern planes where precision is a must. Digital does not make a servo stronger or faster, that's still a function of the drive motor and gearing. The actual difference between a digital and analog servo is the number of times it updates positioning input in a given amount of time. The digital does it about 100 times faster than does an analog. This keeps the servo from "wandering" off it's desired position between updates.

As for your radio being digital, all that means is adjustments are made via electronic pushbuttons with the results displayed on a screen rather than using dash pots with a graduated scale on the face of the transmitter. You are still sending the same signal as any conventional surface transmitter so you have nothing to gain by using digital servos with your "digital" transmitter.

That said, the only thing using digitals in an off road buggy does is force to be extra careful with your EPA's. If you set a digital servo EPA just a tiny bit past the physical limit of the linkage you have it attached to, you risk burning it out due to the extremely high refresh rate. Digitals are also big power hogs so you will also need to use a larger capacity receiver pack to compensate. For my money the Airtronics 94357 for throttle and 94358 for steering is the ideal combination for an 8th competition buggy. They are plenty fast and strong to do the job and they are like an anvil, almost indestructible.

RE: Servos
 

Thats exactly what I was after FHM, thanks :D I thought the transmitter had to be "digital" (not in the display sense) too though. A digital servo will work with any radio?

Anyways, I ended up getting the XS3 Pro and an Airtronics 358. I'll use the 358 for steering duty and the Z590 (think thats what the radio comes with) for throttle duties (85oz/.15sec), should be a good match for braking.