Servos

[SnakEyez151]

Lookin at my Savage and I've come to the conclusion that my Airtronics 357 just isn't powerful enough for the wheels. I always assumed it was due to the old style servo saver, but readin over a bunch of posts, 125oz torque isn't enough for an MT. Would it be overkill for my XXX NT tho? I'm thinkin put that up front, and move the z590 to the throttle. Lookin at the specs on the two, thinkin it might be just right?
_________________________
Airtronics 94357
Torque: 125 oz/in
Speed: 0.07 sec
Dimensions: 1.54 x 0.79 x 1.47
Weight: 2.12 oz
Geartrain: metal/plastic
Motor: Coreless

JR Z590m (current steering servo)
Torque: 85 oz/in at 6V
Speed: .15 sec/60° at 6V
Dimensions (WxLxH): 1.55 x 0.73 x 1.46in
Weight: 1.6 oz
Gears: metal
Motor Type: 3-pole ferrite

 

[robmob]

The 357 would be perfect as a steering servo the XXX NT. It's a much lighter rig with puny tires compared to a MT. It will have plenty of torque to turn the wheels and is lightning quick. I put one on my sons electric pede and what a difference it made.

 

[olds97_lss]

I agree with robmob. 125oz would do well on a stadium. Typically you want higher speed on a stadium. So, if it's at least as fast as the 590, then you will get better holding power as well.

For a MT, you want 150+ oz of torque for steering. I also run 130+ for throttle/brake on MT's due to the excessive use of brakes for air control and for the weight of the vehicle. Using lighter duty servo's (I said duty...) for throttle/brake for me in the past just always ended with a burned up servo. I typically run a 645MG or futaba S3305. Neither are blistering fast, but they do have good enough torque to really grind my mammoth, savage and revo to a stop in almost any conditions.

I use the 645MG for steering as well, but for all three (especially the mammoth and savage), it just doesn't have enough torque to get the job done well.

I found another servo that is quite a bit faster and quite a bit more powerful for about $70. Another bonus is that it has o-rings to make it water resistant from the factory. The hitec 985MG. Tower doesn't list the 6v speed/torque, but on the side of the box, speed at 6v is .13sec for 60 degrees @ 172.20oz inch of torque. I installed one of these for steering in my mammoth, but I haven't driven it since (about 2 months ago) as the engine on it still needs more fuel run through it to finish breaking it in. I want to wait until it's warmer out. But, the servo swings the tires much faster and with much more authority than the 645MG it replaced. I'll probably get one for my revo and savage as well as funding allows.

 

[SnakEyez151]

*foot in mouth* well, i tore into my Savage and pulled out my servo - guess what I find? Its a 358.. not 357! Doh! Well, Atleast I get to do that single-servo mod to my Revo now! Ha I feel like a moron - I wonder where I got 357 from tho? I even pulled the plastic servo case out of the trash (Its been the keeper of my spare servo screws/shims/etc for the last year or so) and it reads right on the sticker "94358". LOL Well, that JR 590m is just going to have to do for a while...

This works out better. I'll drop in a new throttle servo and my extra reciever and be able to use my Revo and my XXX NT with my MX3. Atleast I know what servo to get for my XXX NT if I get around to racing it!