R/C Tech Forums

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

Reply
 
Thread Tools Search this Thread
Old 04-03-2007, 11:26 PM   #1
Tech Master
 
Speedie's Avatar
 
Join Date: Feb 2003
Location: Wisconsin
Posts: 1,844
Default Roll Center Program?

Hi I am looking for a free roll center calculator for regular or rc cars. If you know of any please let me know thanks.
__________________
www.victoryhobbies.com Greenbay, Wisconsin
Speedie is offline   Reply With Quote
Old 04-04-2007, 12:06 AM   #2
Tech Elite
 
Brian McGreevy's Avatar
R/C Tech Charter Subscriber
 
Join Date: Jan 2003
Location: Illinois
Posts: 4,081
Trader Rating: 10 (100%+)
Send a message via AIM to Brian McGreevy Send a message via Yahoo to Brian McGreevy
Default

That'd be a rather hard thing to come by. Roll center depends on a minimum of 4 separate variables (inner and outer camber link and arm pin heights), and realistically as many as 6. Not only that, you'd have to know those heights before you plugged them into the said calculator.
__________________
USVTA Member #211

Support Formula SAE - get kids into engineering!
http://motorsports.illinois.edu/
Brian McGreevy is offline   Reply With Quote
Old 04-04-2007, 12:21 AM   #3
Tech Addict
 
DrOlds's Avatar
 
Join Date: Oct 2003
Location: Kansas City
Posts: 644
Trader Rating: 4 (100%+)
Default

They're out there-full size dirt oval racers use them all the time.Don't know if you're going to find one for free though.
DrOlds is offline   Reply With Quote
Old 04-04-2007, 02:13 AM   #4
Tech Elite
 
sosidge's Avatar
 
Join Date: Dec 2001
Location: Bristol, UK
Posts: 3,865
Default

I did once find one that had been done in a spreadsheet for RC cars. However as I recall one of the calculations was wrong so it needed a little correcting. Unfortunately I have now forgotten where I found it - but it may still be out there.
sosidge is offline   Reply With Quote
Old 04-04-2007, 05:28 AM   #5
Tech Adept
 
Join Date: Dec 2003
Posts: 159
Send a message via ICQ to elvo
Default

Didn't john Stanahan make that spreadsheet ?
elvo is offline   Reply With Quote
Old 04-04-2007, 10:04 AM   #6
Tech Addict
 
Join Date: Apr 2005
Location: north-west Indiana
Posts: 746
Trader Rating: 18 (100%+)
Default

I googled roll center calculator and came up with this.
roll center calculator
There are a lot of measurements you need for it though, I hope it works.
trilerian is online now   Reply With Quote
Old 04-04-2007, 12:19 PM   #7
Tech Fanatic
 
Join Date: Jun 2006
Posts: 872
Trader Rating: 35 (100%+)
Default

That one isn't free though :/ Are you just looking for a spreadsheet that shows you height or looking to get the thing actually plotted? I think I can get access to all the proper formulas to calculate it.
__________________
High Desert Raceplace, Grand Jct CO, Sanwa Exzes Plus Stick Radio, Spektrum,Thunderpower 230g, Modified Tri-Nut Novak GTB2, Ballistic 4.5t 550, 5.83lb SCTE Ten, Novak Sentry Brushless Dyno, Crossweight Setup Station, Junsi 20A power supply Icharger 20A Charger,TP610C, 22B, Novak Edge, Novak 13.5, SC10, Havoc Pro SC XDrive, Ballistic 17.5 Matthew Joseph Cordova
mattnin is offline   Reply With Quote
Old 04-04-2007, 04:03 PM   #8
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

Here is a link to a free roll center spreadsheet calculator that I wrote. You need Microsoft excel for it to work. The link goes to a post on the Pantoura Thread. Down lower in the post is a link to the free download. The post has an example of its use and a sample output. I had the wrong units on one of the outputs in the very first draft. This has long since been corrected.

http://www.rctech.net/forum/showthread.php?p=2981627&highlight=roll+center+cal culator#post2981627

John
John Stranahan is offline   Reply With Quote
Old 04-05-2007, 02:01 AM   #9
Tech Master
 
Speedie's Avatar
 
Join Date: Feb 2003
Location: Wisconsin
Posts: 1,844
Default

Thanks John Ill give that a try. At one time I had found a nice calculator that was free but I cannot find it or remember where I got it from. I can figure it out manually but just looking to save some time as I use roll centers alot racing dirt late models.
__________________
www.victoryhobbies.com Greenbay, Wisconsin
Speedie is offline   Reply With Quote
Old 04-05-2007, 02:48 AM   #10
Tech Elite
 
rcfoolz's Avatar
 
Join Date: Sep 2003
Posts: 3,327
Trader Rating: 22 (100%+)
Send a message via Yahoo to rcfoolz
Default

up till now, i didn't understand the reason behind the inner pivot point on the front of the car. now I understand why when I raise it up, steering goes away.
__________________
Am I going back racing?...Hmmm.. Not anytime soon... But soon enough.
rcfoolz is offline   Reply With Quote
Old 04-05-2007, 02:26 PM   #11
Tech Elite
 
Join Date: Aug 2002
Location: Houston, Texas
Posts: 3,777
Trader Rating: 27 (100%+)
Send a message via AIM to John Stranahan
Default

Here are some adjustments and their effect on roll center.

Inner upper pivot up - roll center down
Outer upper pivot up - roll center up
inner lower pivot down - roll center down

When using a standard front ball diff on an electric 4 wheel drive touring car I have found that lowering the roll center will give more traction to that end of the car.

When using a locked front diff on an electric 4-wheel drive touring car. Torque steer seems to be the predominant force driving the steering. In this case lowering the roll center in front will give less torque steer and as a result less steering traction. This assumes you are cornering with good power applied mid corner.

John
John Stranahan is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
Roll Center WisRacr1 Electric On-Road 35 01-07-2012 11:11 PM
Roll Center question TEM Electric On-Road 1 01-31-2006 11:19 PM
Roll Center Products jdesoto Nitro On-Road 0 10-28-2005 04:48 PM
Roll Center Software Oasis2001 Electric On-Road 2 09-27-2004 08:14 AM
Roll Center question ScottyP Australian Racing 48 02-08-2003 04:00 AM



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 07:40 PM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net