Go Back  RCU Forums > RC Airplanes > Kit Building
 Gear Servo fried? >

Gear Servo fried?

Community
Search
Notices
Kit Building If you're building a kit and have questions or want to discuss kit building post it here.

Gear Servo fried?

Thread Tools
 
Search this Thread
 
Old 10-09-2010 | 10:24 PM
  #1  
Thread Starter
Senior Member
My Feedback: (1)
 
Joined: Jul 2010
Posts: 185
Likes: 0
Received 0 Likes on 0 Posts
From: Draper, UT
Default 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!
Attached Thumbnails Click image for larger version

Name:	Mk25606.jpg
Views:	28
Size:	54.3 KB
ID:	1513627  
Old 10-09-2010 | 10:32 PM
  #2  
My Feedback: (2)
 
Joined: Feb 2002
Posts: 6,204
Likes: 0
Received 1 Like on 1 Post
From: Leander, TX
Default 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
Old 10-09-2010 | 10:34 PM
  #3  
JNorton's Avatar
My Feedback: (2)
 
Joined: Jan 2002
Posts: 4,338
Received 3 Likes on 3 Posts
From: Coopersville, MI
Default 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
Old 10-10-2010 | 02:20 AM
  #4  
mboland's Avatar
 
Joined: Jul 2007
Posts: 559
Received 0 Likes on 0 Posts
From: BouldercombeQueensland, AUSTRALIA
Default 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>
Old 10-10-2010 | 10:03 AM
  #5  
Lnewqban's Avatar
 
Joined: Apr 2007
Posts: 4,057
Received 0 Likes on 0 Posts
From: South Florida
Default 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.

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are On



Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.