Gear Servo fried?
 

Iinstalled my gear servo in my Corsairtonight (HItec HS 55) and after a few tests it quit working. (Ithink Ifried it) It has only 16oz of torque, and Idon't think that's enoughfor the robart air valve. An Iright?How much torque do I need in a 4.8 volt system. What's a good micro servo for this? Or do Ineed to use a full size servo? This in my first attempt at hooking a servo to an air valve. Photo of how I set it up is below...
Thanks!

RE: Gear Servo fried?
 

I've always used a std servo. But I imagine a 24oz or around there would work, maybe an HS81 or there abouts. I'm not up to date on the smaller servos. I DO think the micro would be too small for my comfort level. Just my opinion.
Edwin

RE: Gear Servo fried?
 

Well you know 16 oz of torque isn't enough. :( I'd just put a normal servo in it's place, something like an HS-425. You have the room and it certainly doesn't weight that much more. You need to make sure it doesn't bind fully retracted or extended. I'd use an adjustable arm or a servo saver.
John

RE: Gear Servo fried?
 

<div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; padding-top: 0px; padding-right: 0px; padding-bottom: 0px; padding-left: 0px; background-image: initial; background-attachment: initial; background-origin: initial; background-clip: initial; background-color: rgb(255, 255, 255); font-family: Arial; font-size: 12px; ">Of the dozen or so models with retracts I have setup, all have used micro servo's as you have used, mostly JR as I am not a fan of the HS55, had too many fail for no good reason.<div>
</div><div>But</div><div>
</div><div>I have fried a couple, but not from over work, but over travel.</div><div>
</div><div>Make sure your air valve is lubed, and use the shortest arm on the servo that will give sufficient travel, and all should be good.</div><div>
</div><div>
</div></div>

RE: Gear Servo fried?
 

Being fed by 4.8 volts, that servo can produce an output torque = 15.27 oz-in

A direct linkage connected to ~0.3" arm will see a lineal force of:

15.27 oz x 1 inch = Linear force x 0.3 inch

Then, Linear force = 15.27 oz x 1 inch / 0.3 inch = 52.3 oz = 3.2 lb

Hang that weight from your valve until you find out how much force it needs to operate.

Double that force value and do the math in reverse to find out the minimum torque needed at an arm lenght that provides the linear movement that the valve needs without binding the servo.

Then do the math to calculate the rated torque for one inch arm, which is how servos are specified.

I have learned here in RCU that any servo smaller than standard size suffers from vibration in planes with combustion engines.
Even for electric power, always isolate your servos from the plane structure.
The electronics inside the servos are delicate regardless the output torque.