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Old 04-10-2009, 11:32 PM   #31
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Bobw, you're a master!!!!

Excellent job and way more excellent and valuable setup tool.

Especially if you think that the Losi is almost a neglected car, here in Italy.

Bust is a superb one.

It helps me a lot to understand why I like the car better when I've high diameter tyres (we race foam on asphalt).

Just a question, when you change the camber location, in terms of offsets, would be possible having also a graphic change?
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Old 04-11-2009, 05:41 AM   #32
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Hey BobW...

Took the losi for a run and tried some different rollcenter settings based on what I learned from your program and was able to improve the balance and come up with 2 settings that give great balance and different properties.

Thanx again.
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Old 04-11-2009, 06:07 AM   #33
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Giorgio, Not sure exactly what you mean. The graphics should update. When you change values on the Model page the graphic changes to display the new geometry. Also when you select different link positions on the setup page the graphic updates to show what you have selected. Can you clarify what you are suggesting?

Dragonfire, that's great, glad to hear it's helping.
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Old 04-11-2009, 07:57 AM   #34
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looks great now i need someone to do a model for the TC5 so i do not screw something up... :-)
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Old 04-11-2009, 08:38 AM   #35
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Send me your car and I'll build a model.

You can do it yourself though. Just click on new model button. Give the model a name and then load in one of the existing Losi models to provide a base to start from. Then you can change the values on the new model screen or save it as is and return to the model screen and change it there.

There have been 200+ downloads of the program so hopefully by now someone has built a model for something other than the Losi. If anybody would like to share the easiest way to do it right now is paste screen shots into word or adobe and then post them here.

Here is the procedure.

On the Model Page with the Front Radio Button selected press Alt-PrintScrn
Go to Word or Adobe and press Ctrl-V to paste the screen shot.

Click on HingePin Shim Button and press Ctrl-V
Go to Word or Adobe and press Ctrl-V to paste the screen shot.

Repeat this procedure for the Inner and Outer Camber Links and the rear suspension as well. When you are done you should have 8 screen shots in the file. Upload and post the file here.

.doc and .pdf examples attached.
Attached Files
File Type: doc ModelSharing.doc (173.0 KB, 367 views)
File Type: pdf ModelSharing.pdf (232.1 KB, 322 views)
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Old 04-11-2009, 12:11 PM   #36
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[QUOTE=BobW;5669584]Giorgio, Not sure exactly what you mean. The graphics should update. When you change values on the Model page the graphic changes to display the new geometry. Also when you select different link positions on the setup page the graphic updates to show what you have selected. Can you clarify what you are suggesting?
QUOTE]

BobW
Don't know if it's me or my XP, I saw graphic change if I change the camber value (say from -2 to -3).
What is not changing is the camber location.
For instance: the graphic show the rear upper link at 8B (losi code..), if I move inner Horoffset -3.6 (7), the graphic is always at 8B.

Even if I hit "redraw"

Also, by moving to 7 the system say that there is no change in the roll center

I that true or is just me?

Once again, thanks for the wonderful tool you've done!!!
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Old 04-11-2009, 02:50 PM   #37
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Giorgio,
Ok I think I understand what's happening. You are trying to change the position the camber link is connected to by changing the horizontal and vertical offset values using the Alternate Inner Position button. This won't work as you want.

If you want to see changes to the Rollcenter and Camber Gain you do this from The Setup page. On the setup page just click on the graphic inner camber pivot position you want and the link will change and the displayed Roll Centre and Camber Gain Value will change based on the new geometry.

The Model page is only for defining the Suspension Geometry. I know there is a roll centre number displayed on this page but it is only for the base model values that are displayed on the screen. When you click on the "Alternate Inner Positions" button what you are doing is just entering the values for the alternate positions on the shock tower. In the graphic display of the pop-up window the cross hair with the circle represents the location of the Base X2,Y2 point on the Model screen. The simple crosses represent the values that you have been entered in HorOffset and VertOffset table that is displayed.

So If you want to see the roll centre and camber gain values for a specific setup, do this from the Setup page not the Model page.

I think I need to work on a simple Users manual to help explain the operation.
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Old 04-11-2009, 02:54 PM   #38
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BobW,

I'm not sure how you visualize the need for 3D graphics. I've seen some simple 3D techniques applied in the free MS development tool XNA Studio:

http://www.microsoft.com/Express/GameDevelopment/

Also I'm studying the free Google Sketchup 7 as a tool to create Race Track Profiles. It can draw curves to scale for flat corners, link by straight lines, and produce a track map to study braking points and make elapsed time estimates.

Sketchup has a 3D engine that may or may not support an export of graphic files for use in other rendering tools.
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Old 04-11-2009, 03:07 PM   #39
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Quote:
Originally Posted by BobW View Post
Giorgio,
Ok I think I understand what's happening. You are trying to change the position the camber link is connected to by changing the horizontal and vertical offset values using the Alternate Inner Position button. This won't work as you want.

If you want to see changes to the Rollcenter and Camber Gain you do this from The Setup page. On the setup page just click on the graphic inner camber pivot position you want and the link will change and the displayed Roll Centre and Camber Gain Value will change based on the new geometry.

The Model page is only for defining the Suspension Geometry. I know there is a roll centre number displayed on this page but it is only for the base model values that are displayed on the screen. When you click on the "Alternate Inner Positions" button what you are doing is just entering the values for the alternate positions on the shock tower. In the graphic display of the pop-up window the cross hair with the circle represents the location of the Base X2,Y2 point on the Model screen. The simple crosses represent the values that you have been entered in HorOffset and VertOffset table that is displayed.

So If you want to see the roll centre and camber gain values for a specific setup, do this from the Setup page not the Model page.

I think I need to work on a simple Users manual to help explain the operation.


Bobw for president!!!!!!

Being a technician I choose the most complicated way and not the easiest...

This stuff is great!!!
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Old 04-11-2009, 06:53 PM   #40
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I have created a simple users manual that should help anyboby who is having problems. You can download it here.

http://www.mediafire.com/file/ylfxnr...UserManual.pdf
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Old 04-11-2009, 06:57 PM   #41
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Thanks for all the great feedback guys. Keep it coming.
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Old 04-12-2009, 11:26 PM   #42
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Quote:
Originally Posted by BobW View Post
Thanks for all the great feedback guys. Keep it coming.
Bob,

I must say that the program you wrote is bang on.. I say this because I compared camber gain that is calculated in the software to my actual car while having it sitting with a setup station. The results are almost the same. I imagine if a digital version of a setup station would read. I assume that the readings would be even closer.

The one question I think of, is where the centre of gravity point is. On average where would this be?
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Old 04-13-2009, 05:45 AM   #43
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Heh MaxRain, Hello to a fellow Canadian Eh!

I did my best to ensure that the program generates accurate results. The Roll Centre and CamberGain were both verified using a 2D CAD model so as long as the input geometry is accurate the results should be too.

As far a the CofG is concerned I have never measured it. If I had to guess though I would say between 15and 20mm up from the underside of the chassis. There are ways to measure it using balance points or the 4 wheel scale method posted earlier.
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Old 04-14-2009, 07:43 AM   #44
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BobW, I don't use the JR links on my Losi. I use ball studs instead. I'm guessing that I need to change the LKing measurement in the model page? What measuring points do I use? Center of the pin to the center of the ball stud?
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Old 04-14-2009, 01:18 PM   #45
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Quote:
Originally Posted by 4wheeldrift View Post
BobW, I don't use the JR links on my Losi. I use ball studs instead. I'm guessing that I need to change the LKing measurement in the model page? What measuring points do I use? Center of the pin to the center of the ball stud?
The last model in the drop down list is the JRXS R with the ball stud link. A word of caution though I haven't accurately measured these positions. They are approximate. If you want the number to be accurate then the Lking and LCambLnk values need to be measured. The Lking value is the most difficult to measure. It is the distance from the centre of the outer hinge pin to the centre of the ball stud. Obviously the LCambLnk value is the centre to centre distance between the camber link pivot points.

Hope this helps.
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