R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Electric On-Road

Reply
 
Thread Tools Search this Thread
Old 06-30-2011, 12:29 PM   #16
Tech Adept
 
Join Date: Oct 2010
Posts: 210
Default

Quote:
Originally Posted by terry.sc View Post
That's a glitching servo issue. Unplug the servo from the receiver and the wheels shouldn't steer to the right when you blip the throttle.


The 'torque steer' effect can be seen on a belt drive car, pick it up and hold it in the air halfway along the chassis. When you blip the throttle the front end will lift and the rear end will drop. This torque effect on the chassis on a belt drive car helps push the rear wheels down under acceleration for more grip to put the power down. But with the motor in a shaft drive chassis this same motor torque will lift one side of the chassis while pushing down on the other, causing it to steer one way under acceleration and steer the other way when braking. As Daleburr pointed out, with the lighter armatures in brushless motors today the effect isn't as noticeable as it used to be.
nope, i tried 3 different servos of different brands, a different RX, different crystals, none did anything.
look at this car, its quite similar. Notice how the rear tires also move about a bit but the suspension geometry does not let them turn

http://www.youtube.com/watch?v=xynXQnJ3uCM
kb525 is offline   Reply With Quote
Old 07-03-2011, 06:42 AM   #17
Tech Addict
 
academygaz's Avatar
 
Join Date: Apr 2005
Location: UK
Posts: 718
Default

Quote:
Originally Posted by kb525 View Post
nope, i tried 3 different servos of different brands, a different RX, different crystals, none did anything.
look at this car, its quite similar. Notice how the rear tires also move about a bit but the suspension geometry does not let them turn

http://www.youtube.com/watch?v=xynXQnJ3uCM
Thats a shaft drive car with a broken rear differential, so its not applying power to all 4 wheels evenly.

And you DO have driveshafts to connect the wheels to the diff, one of yours has to be bent.

Trust me and all the other experienced guys on this thread, your issue has been explained at least twice by now as we've listed all the possible problems. Either you're not spotting the problems (because you think they are OK when they actually aren't), or one think not mentioned so far is unbalanced wheels (one being slightly heavier than others, even by half a gram).
__________________
Quote, Leodis, 2007: ''I've been shopping online for 9 years and the only charge I've ever had to dispute with my credit card company was from TiR. Congratulations TiR. Even porn sites are more ethical than your company!''

RC cars - I haz sum.
academygaz is offline   Reply With Quote
Old 07-03-2011, 04:48 PM   #18
Tech Regular
 
Join Date: Feb 2011
Posts: 311
Default

Wow gone for a couple of days sorry to start a war.My car will pull a little to one side at the start I read that the belts had a little give and that helps so i thought if u had a slipper it would do the same.
bosco72 is offline   Reply With Quote
Old 07-03-2011, 10:59 PM   #19
Tech Adept
 
Join Date: May 2006
Location: sunny Cancun, Mexico
Posts: 214
Trader Rating: 1 (100%+)
Default

that is steering slop there, not torque steer. All hpi sprint 2's have it.
Yo can get rid of it (mostly) by doing some minor mods to reduce play on some of the plastic parts fitting, head over to the official hpi sprint thread somewhere around here. it's a bit hard to explain without the pictures, but the info is there...
Rufus2000 is offline   Reply With Quote
Old 07-04-2011, 12:51 AM   #20
Tech Champion
 
Radio Active's Avatar
 
Join Date: Jun 2003
Location: Newcastle, Australia
Posts: 7,071
Trader Rating: 2 (100%+)
Default

The effect daleburr describes is real and well described. It is too small to notice most of the time in RC, especially in slower classes. Keep in mind better drivers are more sensitive to small handling 'features' so while the top guys might say they don't like shaft drive because of torque steer most of the rest of us won't notice it even when we are going quick.

I have a PhD in Physics.
__________________
Reigning NSW 4WD Group 20 Champion
Member: Maitland Radio Car Club (http://www.morcc.com.au)
twitter: @dvcotton
Australian 12th Scale hastag: #EP12AU
Radio Active is online now   Reply With Quote
Old 07-04-2011, 12:56 AM   #21
Tech Champion
 
Radio Active's Avatar
 
Join Date: Jun 2003
Location: Newcastle, Australia
Posts: 7,071
Trader Rating: 2 (100%+)
Default

Oh, and no, the slipper won't help with torque steer. It will make the car more driveable though. And yes, a slipper clutch is banned for sanctioned TC racing in most places.

Quote:
Originally Posted by IFMAR Electric Track Rulebook
4.6.3 The fixed single ratio transmission may not include a mechanical device/ s between the drive motor output and the gearbox input for the purpose of controlling torque (e.g. ‘slipper’ clutch/fluid clutch).
__________________
Reigning NSW 4WD Group 20 Champion
Member: Maitland Radio Car Club (http://www.morcc.com.au)
twitter: @dvcotton
Australian 12th Scale hastag: #EP12AU
Radio Active is online now   Reply With Quote
Old 07-04-2011, 08:37 AM   #22
Tech Regular
 
Join Date: Feb 2011
Posts: 311
Default

I have the exceed madspeed the chassis is nice but the electronics sucked So i put a brushless in. i have just a little play in the arms i was going to buy associateds spacers to adj. them.Also i was going to buy the tamiya hitorq servo saver will that work.
Attached Thumbnails
shaft drive idea-madspeed-hooked-001.jpg   shaft drive idea-madspeed-hooked-002.jpg  
bosco72 is offline   Reply With Quote
Old 07-04-2011, 09:45 AM   #23
Tech Adept
 
Join Date: Oct 2010
Posts: 210
Default

Quote:
Originally Posted by academygaz View Post
Thats a shaft drive car with a broken rear differential, so its not applying power to all 4 wheels evenly.

And you DO have driveshafts to connect the wheels to the diff, one of yours has to be bent.

Trust me and all the other experienced guys on this thread, your issue has been explained at least twice by now as we've listed all the possible problems. Either you're not spotting the problems (because you think they are OK when they actually aren't), or one think not mentioned so far is unbalanced wheels (one being slightly heavier than others, even by half a gram).
Ta05 is belt no?
kb525 is offline   Reply With Quote
Old 07-04-2011, 09:46 AM   #24
Tech Adept
 
Join Date: Oct 2010
Posts: 210
Default

Quote:
Originally Posted by Rufus2000 View Post
that is steering slop there, not torque steer. All hpi sprint 2's have it.
Yo can get rid of it (mostly) by doing some minor mods to reduce play on some of the plastic parts fitting, head over to the official hpi sprint thread somewhere around here. it's a bit hard to explain without the pictures, but the info is there...
I was sure it had to be something like that. But the effect is the same as torque steer.
kb525 is offline   Reply With Quote
Old 07-04-2011, 01:38 PM   #25
Tech Addict
 
Join Date: Nov 2009
Location: Denmark
Posts: 562
Default

Quote:
Originally Posted by kb525 View Post
Ta05 is belt no?
He doesn't say that it isn't. But even a belt-driven car has driveshafts - from the diffs to the wheel. How would you transfer the power to the wheel without them?
__________________
Niklas Hansen
Team TCHobby / Team Upgrade-RC
Tamiya TRF417 / Speed Passion GT2.0 / Speed Passion V3 motors.
Nilks is offline   Reply With Quote
Old 07-04-2011, 07:23 PM   #26
Tech Champion
 
MantisWorx's Avatar
 
Join Date: Jun 2010
Posts: 5,918
Trader Rating: 28 (97%+)
Default

i kinda have to agree with that, im my offroad buggy with a 4.5t jumping triples the car remains flat even at full throttle, if shaft drive effect tq steer the car would try and turn sideways or do something funky in the air. 99% of off road cars are shaft drive, with soft suspensions and insane tq (4pole motors) you would have to think TQ steer would be more obvious in off road. if i hold my buggy in my hand and floor it it goes up and down just like my belt TC. not saying that TQ steer doesnt exist but i always thought it came from unequal shaft lengths as stated before. its just funny how belt drive ruled, then shaft and now back to belt. maybe the laws of physics are changing! i dont think power has much to do with it, back in the day there were still 10t single motors that put out pretty good although they only lasted about 3 minutes on a battery
MantisWorx is offline   Reply With Quote
Old 07-05-2011, 02:25 AM   #27
Tech Addict
 
Join Date: Nov 2009
Location: Denmark
Posts: 562
Default

My theory is that the center-diff will remove / hide "TQ steer", and because of that buggies are not affected.
__________________
Niklas Hansen
Team TCHobby / Team Upgrade-RC
Tamiya TRF417 / Speed Passion GT2.0 / Speed Passion V3 motors.
Nilks is offline   Reply With Quote
Old 07-05-2011, 07:14 AM   #28
Tech Champion
 
MantisWorx's Avatar
 
Join Date: Jun 2010
Posts: 5,918
Trader Rating: 28 (97%+)
Default

Quote:
Originally Posted by Nilks View Post
My theory is that the center-diff will remove / hide "TQ steer", and because of that buggies are not affected.
true BUT 10th scale buggies do not have center difs!! i just think it is one of those myths.
MantisWorx is offline   Reply With Quote
Old 07-06-2011, 08:21 AM   #29
Tech Master
 
heretic's Avatar
 
Join Date: Aug 2006
Location: europe
Posts: 1,105
Default

Wrong. torque steer is very real even in that case, only your tires are so much more heavy, possibly unbalanced, centrifugating etc, that it hides the torque steer from the motor.

Again, the armature of a BL motor is so much more lighter than a brushed one, that the effect is barely noticable for us mere mortals.

Bertrandv87 : I believe the tc3 ( and the tc4, someone correct me if needed) have some degree of asymmetry to help fight torque steer.

I.e more rear toe-in toe on on one side, or more caster on one side on the 2* and 4* items. Something you would have noticed if you used a setup station.

I had the opportunity to handle one of the very first protos of the HPI pro4, shamelessly copied from the TC3 . You just wouldn't believe how many asymmetries you could find. More rear droop on one side, more rear toe in on one side, more caster on one side... That 's how you got a shaft car to work apparently.
__________________
I love wedge bodies. I love dish wheels.
heretic is offline   Reply With Quote
Old 07-06-2011, 08:27 AM   #30
Tech Master
 
heretic's Avatar
 
Join Date: Aug 2006
Location: europe
Posts: 1,105
Default

Quote:
Originally Posted by IndyRC_Racer View Post
In response to the original post, there is a way to put a slipper on a shaft drive car. A company call RC Product Designs has an offroad conversion for the TC3. The offer a slipper assembly for that car. For more information, check out their website (http://www.rcproductdesigns.com/)
good idea but you'd still have to refabricate a shorter center shaft.

Slippers on TCs are a stillborn idea, only found on the first RS4, I can't even think of another one.

Hell I have the v2 of the TC3O, without a slipper and the car is really good even on loose dirt. Throttle control !
__________________
I love wedge bodies. I love dish wheels.
heretic is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Best Shaft drive touring now ioxqq Electric On-Road 53 01-05-2010 06:28 AM
Shaft Drive TC Yub, yub, cmdr! Electric On-Road 133 04-15-2007 11:22 AM
Prototype Xray 007 Shaft Drive Barry White Electric On-Road 38 03-11-2007 07:08 AM
Shaft Drive or Belt Drive? dino.tw Nitro On-Road 109 05-25-2004 11:04 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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



All times are GMT -7. It is currently 02:24 PM.


We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net