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Old 07-20-2009, 10:25 PM   #1531
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Originally Posted by CraigM View Post
I believe in order from most ackerman to least it goes

rear 12
rear 11
rear 10
rear 9
middle 12
middle 11
middle 10
middle 9
front 12
front 11
front 10
front 9

that's what I got from Josh's comment:
Better check that again M8.... I think thats backwards.
But then again I'm dyslexic.
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Old 07-21-2009, 04:15 AM   #1532
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Originally Posted by CraigM View Post
Maybe we are reading the sheet differently. To me it would logically go from highest RC setting to lowest, left to right:

high up, high down, mid up (FR), mid down (FF), low up, low down

These would be hinge pin positions, not the position of the mark on the eccentric inserts, so maybe that's the confusion. Anyway, I'm definitely running antidive
Craig,

Yes that is the height of the hingepins / suspension mounts in order on the setup sheet but FR is the rear of the front arm and FF is the front of the front arm. If your set up sheet is correct then you are running pro dive because the front of the front arm is lower the rear of the front arm.

Unless I'm mistaken, front kickup = anti dive.

I think we need Josh on here to sort out all of us school kids...
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Old 07-21-2009, 04:49 AM   #1533
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If the front edge of the front arm is higher than the rear that's anti dive.
If the rear edge of the front arm is higher Han the rear that's pro dive.

On the tamiya cars we used to run 0.5mm pro dive. It's smoothed the car out on entry to the corner.

I'm currantly testing with ackerman positions to see how close I can get the outside wheel lock compared to the inner, I measured it before while running insert 10 in middle position. Outer wheel lock was 24-25 deg and inner was only 16-17 degrees.
When I compared this to other cars, this is was the lowest outer wheel lock of the cars I've measured, with most coming in at about 22-23 (usually only a degree or two lower than inner lock.....

I'm aiming to get it as close as possible to reduce front tyre scrub that I'm getting at the moment.
I'll do some more testing and report back when I get some more quantative data to give rather than theory.

Luke
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Old 07-21-2009, 05:28 AM   #1534
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kickup = pro dive, I am running anti-dive

Luke, forward position with insert 9 will be the least angle between inner and outer wheel, I think the difference is a bit over 5 degrees with that setting.
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Old 07-21-2009, 05:53 AM   #1535
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Quote:
Originally Posted by Luke Hobson View Post
If the front edge of the front arm is higher than the rear that's anti dive.
If the rear edge of the front arm is higher Han the rear that's pro dive.
You have this the wrong way around - Craig M is right. What we would call "kickup" - leading edge of the arm higher than the trailing edge - is a pro-dive geometry.
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Old 07-21-2009, 06:06 AM   #1536
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lol just seen what I wrote lol, yes it's the other way around

From what I've just built up on the car it's 12 that gives least difference between the wheel angles..... The inner bottoms out on the castor block at full lock anyway so a 12 increases the outer angle.... A 9 limits the outer wheel lock the most
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Old 07-21-2009, 06:14 AM   #1537
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Originally Posted by sosidge View Post
You have this the wrong way around - Craig M is right. What we would call "kickup" - leading edge of the arm higher than the trailing edge - is a pro-dive geometry.
+1

But I think he got the Ackermen backwards.

I guess it all depends on where you are looking at the #"s, beginning or end.
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Old 07-21-2009, 06:25 AM   #1538
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+1

But I think he got the Ackermen backwards.

I guess it all depends on where you are looking at the #"s, beginning or end.
Ackermann - increased difference in angle between inner and outer wheels.

So the setting with the most ackermann is back-12. Least ackermann front-9.

That's how I would see it.
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Old 07-21-2009, 06:29 AM   #1539
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Ackermann - increased difference in angle between inner and outer wheels.

So the setting with the most ackermann is back-12. Least ackermann front-9.

That's how I would see it.
If you look at the numbers they change with respect to degree angle of input ..
Id have to look again ,, and again... lol. Initial would be more relevant as most of my kits never get to full lock. Even in the tight turns.

I see what you are saying ... But initial is less in some cases by not much ...
The endpoints are definitely greater so I can see where you are coming from.
That is not always the case on the track.. make subtle changes at the wheel at the input angle you are looking for and not just by the overall degree difference.
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Old 07-21-2009, 06:41 AM   #1540
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Originally Posted by John St.Amant View Post
If you look at the numbers they change with respect to degree angle of input ..
Id have to look again ,, and again... lol. Initial would be more relevant as most of my kits never get to full lock. Even in the tight turns.
Intriguingly the measurements are very linear considering that you are changing both the position on the chassis and the width of the linkages. The order of the settings is identical on 5, 15, 20 and 25 degrees lock, and there is only one sequence change on the 10 degree chart.
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Old 07-21-2009, 07:13 AM   #1541
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Intriguingly the measurements are very linear considering that you are changing both the position on the chassis and the width of the linkages. The order of the settings is identical on 5, 15, 20 and 25 degrees lock, and there is only one sequence change on the 10 degree chart.
Yeah .. thats what I meant ..
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Old 07-21-2009, 07:47 AM   #1542
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Wow... I'm starting to think I shouldn't have put all these adjustments in the car..lol.. Everyone seems confussed.

Ackerman:

21mm (short) Bell Crank w/ #12 Insert is the most ackerman you can run. This means there is a large difference between inside/outside wheel angles when turning.


24mm (long) Bell Crank w/ #9 Insert is the least ackerman you can run. This means there is a smaller difference between the inside/outside wheel angles when turning.

Endpoints:

Usually 25 degrees is the max endpoint setting for most tracks - Anymore than this you will scrub the front tires in excess. I think I posted that the castor block stop is at 30 degrees as we need that extra 5 degrees for some of those really tight indoor carpet tracks just to turn around in the lanes. If you use a .5mm shim between the castor block and steering block (at the stop) then this will get you 25 degrees.

RC:

On the set-up sheet - H = High and L = Low. If you run FF at "M" and FR at "H" then this is anti-dive. If you run FF at "H" and FR at "M" then this is kick-up.
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Old 07-21-2009, 08:22 AM   #1543
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Originally Posted by Josh Cyrul View Post
Wow... I'm starting to think I shouldn't have put all these adjustments in the car..lol.. Everyone seems confussed.
I think people are confused because it's something they haven't had to work with to the degree they do with the Photon and we're climbing the learning curve. Once we've gotten there, it will become old hat and we'll move on to be confused by something else

Now I see how I read the chart wrong! The number along the top of the chart is the degree the inside wheel was from straight, and the number in the chart is what the outside wheel (which is closer to straight) will be turning.
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Old 07-21-2009, 08:31 AM   #1544
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Quote:
Originally Posted by Josh Cyrul View Post
Ackerman:

21mm (short) Bell Crank w/ #12 Insert is the most ackerman you can run. This means there is a large difference between inside/outside wheel angles when turning.


24mm (long) Bell Crank w/ #9 Insert is the least ackerman you can run. This means there is a smaller difference between the inside/outside wheel angles when turning.

Endpoints:

Usually 25 degrees is the max endpoint setting for most tracks - Anymore than this you will scrub the front tires in excess. I think I posted that the castor block stop is at 30 degrees as we need that extra 5 degrees for some of those really tight indoor carpet tracks just to turn around in the lanes. If you use a .5mm shim between the castor block and steering block (at the stop) then this will get you 25 degrees.

.

Finally some clarity! Only one question left just to make sure the horse is dead...

Which of those two settings should provide the most aggressive steering?
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Old 07-21-2009, 08:51 AM   #1545
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Finally some clarity! Only one question left just to make sure the horse is dead...

Which of those two settings should provide the most aggressive steering?
That adjustment makes a difference on where you want the steering to work.
If that makes any sense.. Look back a few posts and read about where Josh tells where center feel and end are different. Too much scrub and overheating tires...
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