R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 01-27-2012, 10:38 AM   #16
Tech Elite
 
Jochim_18's Avatar
 
Join Date: Mar 2005
Location: CALI
Posts: 2,372
Trader Rating: 10 (100%+)
Default

Calibration on your scale is possibly off..
__________________
Localrcracing.com - Your premiere source of Radio controlled Racing in central California.

Visaliahobbies.com * SkyRC * casterracingparts.com
Jochim_18 is offline   Reply With Quote
Old 01-27-2012, 10:38 AM   #17
Tech Regular
 
Conrad's Avatar
 
Join Date: Jun 2005
Location: Scotland
Posts: 473
Trader Rating: 3 (100%+)
Default

I remove tweak in the same way Skiddins and have never had any problems. Remember the corner weights are linked diagonally on the car. So if you have something really heavy on the left rear (passengers side as we drive on the correct side of the road :P) usually the motor then the right front should be heavy as well. So adding half a turn on the left rear shock will increase the corner weight on the left rear and the right front.

I know it's a bit drastic but to eliminate the weight distribution caused by the electronics, you could strip the car back to just a rolling chassis and measure the weights. You would have a good base setting/point of reference then.
__________________
Swith Racing [www.swithracing.co.uk]
Conrad is offline   Reply With Quote
Old 01-27-2012, 11:11 AM   #18
Tech Master
 
Join Date: Jun 2011
Location: Northeast GA
Posts: 1,685
Default

Quote:
Originally Posted by Conrad View Post
I remove tweak in the same way Skiddins and have never had any problems. Remember the corner weights are linked diagonally on the car. So if you have something really heavy on the left rear (passengers side as we drive on the correct side of the road :P) usually the motor then the right front should be heavy as well. So adding half a turn on the left rear shock will increase the corner weight on the left rear and the right front.

I know it's a bit drastic but to eliminate the weight distribution caused by the electronics, you could strip the car back to just a rolling chassis and measure the weights. You would have a good base setting/point of reference then.
Remember he is around 100 g different from left to right. You cannot adjust out that much pressure with the shocks and maintain a consistent ride height unless the ride height and shocks are that far off to begin with. The procedure you describe is perfect to fine tune the balance of the car for optimum handling though.
__________________
3Racing Sakura XI 17.5 TC
Formula Rabbit (FGX conversion) 21.5
STRC LCG 2WD Slash 17.5
Serpent S120 13.5
6376vette is offline   Reply With Quote
Old 01-27-2012, 12:00 PM   #19
Tech Adept
 
jpk4ud's Avatar
 
Join Date: Aug 2011
Location: Ohio
Posts: 220
Trader Rating: 5 (100%+)
Default

I think four of these on a set up board might work well.

http://www.gramscales.com/product_in...roducts_id=822
__________________
Losi SCTE
Losi 22SCT
Slash 2wd
TC5 set up for USGT
The Hobby Shop in Dayton, Ohio

Last edited by jpk4ud; 01-27-2012 at 12:25 PM.
jpk4ud is offline   Reply With Quote
Old 01-27-2012, 12:49 PM   #20
Tech Elite
 
rmdhawaii's Avatar
 
Join Date: Feb 2006
Posts: 3,804
Trader Rating: 4 (100%+)
Default

Quote:
Originally Posted by jpk4ud View Post
I think four of these on a set up board might work well.

http://www.gramscales.com/product_in...roducts_id=822
... and a round bubble level.
__________________
Nitro Knowledge Base: http://nitrokb.netne.net
My YouTube Channel: http://www.youtube.com/nitrokb -> Lots of on-road nitro & eletric action + some off-road as well
My Flickr Photostream: http://www.flickr.com/photos/nitrokb/
Kyosho V-ONE RRR WC (x2) \ XRAY T2'007 \ Also owned: XRAY NT1 & Mugen MTX-4
rmdhawaii is offline   Reply With Quote
Old 01-27-2012, 12:57 PM   #21
Tech Adept
 
jpk4ud's Avatar
 
Join Date: Aug 2011
Location: Ohio
Posts: 220
Trader Rating: 5 (100%+)
Default

Quote:
Originally Posted by rmdhawaii View Post
... and a round bubble level.
Yes and there is a nice phone app for that.
__________________
Losi SCTE
Losi 22SCT
Slash 2wd
TC5 set up for USGT
The Hobby Shop in Dayton, Ohio
jpk4ud is offline   Reply With Quote
Old 01-27-2012, 01:45 PM   #22
Tech Elite
 
Skiddins's Avatar
 
Join Date: Feb 2006
Location: Windsor, UK
Posts: 4,761
Default

Having fiddled around with top deck screws etc I've managed to get it to around 40-50g difference left to right at each end, which is still better than it was. Next up will be attaching the wheel's and shocks
__________________
Xray T4'18, T4'14 (Wet Car)
Xray X12 2018
Xray X1'16
wlrc.co.uk (West London Racing Centre)
RCDisco.co.uk
Skiddins is offline   Reply With Quote
Old 01-27-2012, 03:54 PM   #23
Tech Elite
 
2-Bad's Avatar
 
Join Date: Jan 2003
Location: Australia
Posts: 2,725
Trader Rating: 24 (100%+)
Default

Use setup wheels for accuracy.
Normal wheel & tyres can be different weights, the plastic wheel maybe twisted, etc...
__________________
Yokomo * G Force * Sanwa * SMC * ProSpec
2-Bad is offline   Reply With Quote
Old 01-27-2012, 04:21 PM   #24
Tech Master
 
Magnet Top's Avatar
 
Join Date: Dec 2008
Location: Seattle
Posts: 1,965
Trader Rating: 4 (100%+)
Default

Hey Skiddins,
Maybe you tried this already... but something that is overlooked is that the shock tower can rotate slightly while tightening the 4 screws that hold the shock tower to the "upper clamps". Xray doesn't use countersunk holes so there is more chance for "shock tower tweak" or so I call it. It is also important which side the screws are on ( depending on which chassis it is ). On the Xray T2 and 3 the screws are on the back of the rear shock tower, and front of the front shock tower. So when tightening the screws it twists the two towers in opposite directions ( clock wise and counter clock wise ) ... compounding this diagonal "tweak". And of course, in a wreck, the shock tower could shift too... so I make sure they are tight once I get it right by using opposing force on each tower while tightening. Hope this helps solve it for you.

Cheers,

Jake D.

Last edited by Magnet Top; 01-27-2012 at 04:39 PM.
Magnet Top is offline   Reply With Quote
Old 01-28-2012, 05:17 AM   #25
Tech Fanatic
 
Join Date: Aug 2008
Location: Medina, Ohio
Posts: 761
Default

Quote:
Originally Posted by Skiddins View Post
I understand what your saying but the Integy system uses one scale and three 'stands', and you have to move the scales from corner to corner etc.
I tried it om different surfaces etc to make sure and it was always withina few grammes.

That rules out the scale calibration as you noted. If the tires are on the car try set up wheels or just bare rims. If you still see the differences then the chassis is tweaked as many are stating. Try the twisting as several have suggested.
__________________
www.norcarracing.com
NORCAR @ The Gate
old_dude is online now   Reply With Quote
Old 01-28-2012, 05:54 AM   #26
Tech Adept
 
2themax's Avatar
 
Join Date: Jul 2009
Posts: 198
Trader Rating: 7 (100%+)
Default My scales

This is the setup I use to corner weight the car, the scales cost me about $8 each delivered on ebay.

Max
Attached Thumbnails
Uneven TC Corner Weight-setupscales.jpg  
__________________
Can some let me know the address of the sheep station we are racing for?
2themax is offline   Reply With Quote
Old 01-28-2012, 09:32 AM   #27
Tech Elite
 
sosidge's Avatar
 
Join Date: Dec 2001
Location: Bristol, UK
Posts: 3,865
Default

Corner weighting on RC cars is an imperfect science - I've played with it many times, and it will throw up completely random results at times.

Likely reasons? Domestic-quality scales, chassis flex, and the free play in components - perhaps.

Using the scales to determine Front/Rear and Left/Right weight balance is reliable. Using them to determine corner weights is not. I tweak the car manually if I feel there is a problem.
sosidge is offline   Reply With Quote
Old 01-28-2012, 02:34 PM   #28
Tech Fanatic
 
Join Date: Aug 2008
Location: Stockport, UK
Posts: 982
Default

Quote:
Originally Posted by Skiddins View Post
The four strips were nut and bolted together when the 3rd hole (used for mounting) was drilled so all the stripes are as close to identical as you can get.

Skiddins
That doesn't mean they are anywhere near identical in length. Unless the holes are a tight fit on a 3mm pin, and you can guarantee the second hole is drilled absolutely perpendicular, you would have to be extremely lucky to get them all exactly the same length. The amount of play of the screws in the first hole will guarantee they are all slightly different lengths, and any play at all in the links when fitting to the chassis will guarantee even more chance of being out. Due to the positioning of the linkages on the arms, any slight difference will then be amplified at the wheel end - if the link mounts to the centre of the wishbone then 0.1mm link difference will translate to 0.2mm difference at the axle. Whichever corner is slightly lower that corner and the opposite corner will be the ones that give the highest weight reading.

Then assuming all of your home made links are exactly the same length, down to tiny fractions of a mm, and the whole chassis/top deck/suspension mounts/shock mounts are all perfectly flat and square, you would still have to make sure you have exactly the same amount of play in axle bearings, uprights, wishbone pivots, etc. to actually get an accurate reading.

Simple way to prove the difference in numbers is down to tweak and not the actual corner weights, put your car as it is on the scale and measure the corner weights. Now wrap a few turns of tape around one of the axles and try it again. You will notice the taped axle and its opposite corner will be 'heavier' while the others will be lighter. If the scale was only measuring the actual corner weight the difference would be the corner with the tape would be a few grams heavier. As you are using fixed links there is no way for the slight tweak to be taken up by the springs.

It is virtually impossible to have an absolutely tweak free chassis and suspension, you dial it out with the shock length, droop screws and spring collars.

If you want to deal with car balance a simple tweak board is a much easier and quicker way of sorting corner weighting than a set of scales.
terry.sc is offline   Reply With Quote
Old 01-28-2012, 07:06 PM   #29
Tech Adept
 
2themax's Avatar
 
Join Date: Jul 2009
Posts: 198
Trader Rating: 7 (100%+)
Default scales

I use my scales to check firstly for tweak, then for front/rear & left/right bias. I have little concern for the actual weight on each wheel, only how it compares with the other scales on the board. As we use a very low racing weight here (1350), I use them to move things on the car to balance it. As a side note, one thing it has shown me is how little impact it takes to tweak the car, and how much it needs to be out to affect the handling. It comes down to one thing for me, you can never have too much information.


Max
__________________
Can some let me know the address of the sheep station we are racing for?
2themax is offline   Reply With Quote
Old 02-03-2012, 01:08 AM   #30
Tech Rookie
 
Join Date: Oct 2011
Posts: 11
Default

Quote:
Originally Posted by DS Motorsport View Post
The most important thing is to make sure the scales are absolutely level.
With our small cars a standard spirit level isn't accurate enough. You want either a digital one with a 0,0x read out or a analog one with a sensitivity of 0,05mm/m.

Personally I prefer the analog 0,05mm/m spirit level, we also use these in professional motorsports.
This is my first post here guys so forgive me (and correct me) if I do something wrong.

DS Motorsport is correct, and don't forget to compensate for variances in SCALE PLUNGER travel (due to the different corner loads). Often times, I find it necessary to shim between tweak board and bottom of scales to get the car back level.
I want to help stress again the point DS Motorsport is making..........THE CAR must be PERFECTLY level (as your referrence) or everything else you do including (but not limited to) caster, camber, and toe settings will be in error.

AGAIN - GET IT LEVEL EVERY TIME!
blacky2kgt is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Duratrax Vendetta TC duneland Micro and Mini Scales 604 01-09-2011 08:59 PM
Weight Balancing With Scale Paul_TC4 Electric On-Road 26 10-23-2004 12:47 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 03:48 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