Go Back  R/C Tech Forums > General Forums > Rookie Zone
Steering Issues on Tamiya XV-01 >

Steering Issues on Tamiya XV-01

Like Tree2Likes

Steering Issues on Tamiya XV-01

Old 05-29-2020, 02:11 AM
  #16  
Tech Champion
iTrader: (1)
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 6,113
Trader Rating: 1 (100%+)
Default

I've been using Spektrum receivers with Hitec servos (even the Hitec HS-7955TG "ultra torque" servo) on 6 volts or less for years without any problems. Never used Savox so I can't comment, but I've heard mixed reviews. Never heard anyone complain about Hitec servos.
fyrstormer is offline  
Old 05-29-2020, 05:36 AM
  #17  
Tech Elite
 
the rc guy's Avatar
 
Join Date: Aug 2016
Location: Detroit
Posts: 2,404
Default

I also run Hitec servos... and just recently has my servo act strange .would not hold a turn,would jump right or left at its whim(whenever)..I was running a castle esc with a 13.5 motor,,took a ubec to solve the issue. I went thru everything I could think of...
the rc guy is offline  
Old 05-29-2020, 10:44 AM
  #18  
Tech Elite
iTrader: (9)
 
IndyRC_Racer's Avatar
 
Join Date: Jul 2006
Location: Indianapolis
Posts: 2,028
Trader Rating: 9 (100%+)
Default

Originally Posted by sleeperx View Post
I swapped the servo with another one (a Savox SC-1252MG) and still did the exact same thing. After more testing, I find that if I hold the steering just slightly left off center, it drives straight. As soon as I let go of the wheel, it'll start turning. Now, I'm really beginning to think I need to set something up on the Spektrum. I watched a bunch of videos on Youtube, but found nothing. And I can't find much reading material.

To me, brown out means it cuts out power? But, there's no issue with power.
SLEEPERX started this thread. Please re-read their most recent post (I have quoted it above). Based on their own response/observations, I would guess that they need to Adjust the steering subtrim on their transmitter (They are using a Spektrum DX5c).

The issue could also be related to the stock Tamiya servo saver. I have found that if you over-tighten the screw that holds the servo saver to the servo AND you are using a high torque servo, the plastic U shaped "spring" in the servo saver may have problems returning the servo saver back to center. In other words, the servo saver can get "stuck" slightly off-center which results in the steering not returning back to neutral. This may result in the car randomly steering to the right or left depending on which position the servo saver gets stuck in. While the stock servo saver should work under normal circumstances, it is worth upgrading it to the Tamiya High Torque Servo Saver as suggested previously.

It is common in this hobby to purchase many things second hand or used. Thankfully most manufacturers offer manuals to download for free. Here are a few links that might help...

Tamiya USA manual download page.
https://www.tamiya.com/english/rc/manuals.htm

Spektrum DX5C manual in .pdf format (from Horizon Hobby)
https://www.horizonhobby.com/pdf/SPM5100-Manual-EN.pdf

I hope this information helps.
IndyRC_Racer is offline  
Old 05-29-2020, 02:04 PM
  #19  
Tech Champion
iTrader: (1)
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 6,113
Trader Rating: 1 (100%+)
Default

Originally Posted by the rc guy View Post
I also run Hitec servos... and just recently has my servo act strange .would not hold a turn,would jump right or left at its whim(whenever)..I was running a castle esc with a 13.5 motor,,took a ubec to solve the issue. I went thru everything I could think of...
Maybe there's a marginally-bad pin connection, or a cracked wire, that is causing the servo to receive less power than it should, and the Castle BEC is able to shove the required amperage through the bad connection.

Anyway, based on the OP's most recent post, it really sounds like the servo trim is off-center. Or possibly the servo horn was knocked off-center by an impact and needs to be repositioned.
fyrstormer is offline  
Old 05-29-2020, 08:04 PM
  #20  
Tech Rookie
Thread Starter
 
Join Date: Jun 2019
Posts: 8
Default

I've made a video of it. As you can see the first go at it, it turns left. When I reverse, it comes back straight. Then I hit the little trim button once and it seems to stop the sharp turns. And I guess the drift is something I have to straighten out. But, it's the initial turn that is weird. Unless I hit the trim button once, it does the turn.

youtu.be/Op_zd1FfFJE
sleeperx is offline  
Old 05-29-2020, 09:00 PM
  #21  
Tech Elite
 
Sir 51D3WAYS's Avatar
 
Join Date: Jun 2011
Location: Stuck in urban hell
Posts: 3,150
Default

Based on that video, I suggest you apply a little trim to the right.

Then see what happens. Post up a second vid.
Sir 51D3WAYS is offline  
Old 05-29-2020, 10:48 PM
  #22  
Tech Champion
iTrader: (1)
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 6,113
Trader Rating: 1 (100%+)
Default

Okay, so you actually have two problems. The slight pull to the left is a simple alignment or trim issue (depending on whether you want to correct it by adjusting the turnbuckles on the car or the settings on the controller). The sharp turn to the left is very strange, but since you say it stops happening after you adjust the trim even a tiny bit, that means there is something physically wrong with your controller. I think you need to make another video of the same problem happening repeatedly in a larger space than your balcony, and then return the controller for repairs along with a link to the video showing the problem.
fyrstormer is offline  
Old 05-30-2020, 07:54 AM
  #23  
Tech Addict
iTrader: (8)
 
Join Date: Nov 2011
Posts: 505
Trader Rating: 8 (100%+)
Default

Originally Posted by fyrstormer View Post
You definitely do not need a 10 amp BEC to power the servo in a rally car. Those things are complete overkill for all RCs, even rock crawlers
Agreed for the rally car... but there are high torque crawler servos out there that will pull 4-5A under full load, and plenty of crawlers with multiple servos out there or run dual steering servos, winch, lights etc... not hard to add up to needing a 10A BEC for a crawler.

To me the issue in the video does look like a physical problem with the steering (could be horn too tight, or too loose, something binding).I suspect a physical problem rather than something with the radio. The sharp turn could be the servo finally pushing past whatever it is binding on, or a loose horn flopping into that position under load. Does the steering sound crunchy when you turn it? It could even be a stripped internal gear on the servo.
mushroomed is offline  
Old 05-31-2020, 10:00 PM
  #24  
Tech Champion
iTrader: (1)
 
fyrstormer's Avatar
 
Join Date: Mar 2014
Location: Maryland, Near DC, USA
Posts: 6,113
Trader Rating: 1 (100%+)
Default

Again, servos do not pull amperage. (nor do any other electrical devices.) They accept and try to use whatever amperage the battery can shove through them, and that depends on their electrical resistance.

Dual steering servos use less power than single steering servos, because the dual servos are under less strain and waste less energy as heat. The only exception to this is if the single servo is incapable of steering the wheels at all, in which case the dual servos appear to use more power, but they still use less power than a stronger single servo would require to do the same work.

LEDs use a few milliamps each. Certainly newer LEDs can handle having multiple amps pushed through them, but RC lights lack the massive heatsinking required to run LEDs at those power levels, so RC lights are limited to 0.05 - 0.1A per LED at most.

Transmission servos also use a few milliamps each, unless the shift linkage is binding, but obviously that problem is solved by fixing the shift linkage, not by shoving more power through the transmission servo.

Mostly, crawler guys have a similar mindset to the guys who used to build all-metal T-Maxxes -- they believe their RC requirements are more extreme than everyone else. It's super-easy to sell excessive equipment to crawler guys.
fyrstormer is offline  
Old 05-31-2020, 10:46 PM
  #25  
Tech Addict
iTrader: (8)
 
Join Date: Nov 2011
Posts: 505
Trader Rating: 8 (100%+)
Default

Originally Posted by fyrstormer View Post
. It's super-easy to sell excessive equipment to crawler guys.
Not sure about the rest of it, but can agree to this!
fyrstormer likes this.
mushroomed is offline  

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
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 On
Pingbacks are On
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.