- Kyosho RB6 - Roger Mills - Feedback - 20.09.2012 -

I built my car MM but built up a RM gearbox assembly at the same time so I could swap between the two quickly.
I tried mine in RM when I went to a soaking wet Kidderminster to see the difference just swapping layout made .... there were no setup changes other than correcting ride height (car is cleverly designed so you don't even need to get the camper gauge out!

Car was easier to drive in slick conditions in RM but once you got you driving adjusted was just about the same pace in MM. Can change between the two in 5 mins so long as you have the soldering iron warming as you pick up the driver.

All other running has been MM.

The shims were originally intended to adjust the hinge pin height when you reversed the front arm mount to change the kick up (and thus total castor) as doing so changes the hinge pin height at its center relative to the chassis.

So for hinge pin height

25deg +0.5 shim = 30deg +1mm shim
25deg + no shim = 30deg +0.5mm shim etc etc

Changing the hinge pin height relative to the chassis moves the roll center of that axle relative to the height of the mass acting on that axle ... same rules as always, further the roll center is from the height of the mass the more affect the mass will have (i.e. try to roll the car more as it moves).
A bit too complicated a topic to discuss in the time I have tonight but in essence if your happy with 25deg +1mm shim but want to try 30deg then you should bolt in both the shims to give 1.5mm and thus the same hinge pin height.

Remember that more castor gives you more through and out of a corner but less bite in ... less castor the opposite.
Now with the RB6 we have two potential castor adjustments, castor inserts which just affect castor, and the hinge pin block which affects both castor and kick-up at the same time (kick-up + castor insert = total castor).
Kick-up works a little like anti-squat but at the front of the car. By that I mean it affects the way the weight transfers around. In the case of kick-up if mainly affects 2 things;

1) the way in which weight transfers forward under breaking (more kick up = more weight transferred forward)
2) the way in which the front of a car goes over sharp bumps / rides up ramp faces (more kick-up allows the impact to be absorbed by the suspension more but results in a loss of ride height ... on steep ramps this means the front of the chassis may bottom unsettling the car ... less kick-up would mean less absorbed by the suspension, less ride height change but in extreme cases the front of the car could be thrown up and the front wheels become unloaded)

With the RB6 having both kick-up and castor inserts you can see the potential for tuning castor and kick-up independently for example;

25 deg kick-up + 4deg castor insert = 29deg total castor
30 deg kick-up + 0deg castor insert = 30deg total castor

These would feel fairly similar to drive so long as the track was flat and didn't have any big breaking zones but different if bumpy/big jumps and big stops.

I would suggest, to start with at least, that you play with the kick-up and castor inserts separately.

I built my car with 30deg + 0deg but might well find that 25deg + 4deg might suit my driving style better ... time will tell.

"slip angle" or anti-squat on the rear. What they are actually saying is the options are; a) 1mm shim - rear hinge pin block - bulkhead = minimum anti-squat
b) rear hinge pin block - 1mm shim - bulkhead = maximum anti-squat
c) 0.5 shim -hinge block -0.5 shim - bulkhead = medium anti-squat

Based on experience with Scorpion I have built my RB6 with option b) and added a 1mm shim under the RF2 forward hinge pin block to gain even more anti-squat.

Remember that the rear anti-squat adjustment potentially affects the hinge pin height in the same way as we discussed with the kick-up plate ... the correct way to make a 1mm change to anti-squat is to move 0.5 from under one block to above the other / remove it.