Wide right arm side oval

[tommykart]

Here is my attempt at a dirt oval racer, although it may take a while to complete but this is what i have started.
Rc10 arms on the left and B3 on the right. T3 tranny mounted on a slant to lower the CG of the motor. B3 drive arms both sides. Custom mounting blocks to lower ride height to about 1/2", projected. Tires are for mock up only, will run calibers on 2.2 rims, what most are running, since the track is loose and dusty.
still have to flip the drive to the other side and make the delrin parts and aluminum shock towers, all the links, bracing etc .
The wheel base is 11 1/4' and with at rear is approximately 9 3/4' with b4 rims 10 1/4' with the b2 rims


Questions
is 3/32" 6061 aluminum thick enough for shock towers?
Are the stock steering rack dimensions good enough to mock up a bearing steering rack from?

[Charlie don't surf]

It's going to be tighter than a drum on entry, and looser than a goose on exit. Here's a short version of why
1) unequal center line, roll centers and dive centers are going to cause crazy weight transfer points and unequal transfer rates, positions and speeds.
2) unequal shock damping rates and spring rates and leverage effects, most oval cats manipulate this with equal leverage points, and through damping and spring differences.
3) battery pack is "loading" the traction points for understeer on entry and exit corners.

Minor geometry changes like the reduction of a suspension arm length by 1/8" has a huge handling effect on DO, those differences would be impossible (imo) to balance even slightly.

[tommykart]

Yes I believe you are right with loading the FR side too much the way the battery sits now, it is a tight fit, and the biggest obsticale, but i don't want to make the wheel base any longer, do I

What i have been reading on here is that with a stock buggy 1) softer springs on load points helps roll and traction 2) unloaded points have stiffer springs to keep tire contact and help with weight transfer

I'll finish a partial mock up and try to scale it and see what kind of numbers I get
If it doesn't work out i'll probably make an off-set mid motor

[cautrell05]

A Shorty lipo pack would work good there.

Nick

[tommykart]

well it turned out to be an interesting project, but there are other factors that needed to be over come as well. with the different make parts there was wheel base length on each side that was slightly different, making what Charlie said very relevant. I did reorganize the battery, servo, and mock esc to better distribute the weight better but over all i think that it would be too hard to tune for minor adjustments.

So for the next project; would a short arm, rc10, or long arm ,B3, be a better direction for an offset chassis??

[SoAzRC]

I've tried the offset route a couple times and did not gain any appreciable advantage on times or handling. I have found that a symmetrical set-up has worked best for me with tuning, LR to RF spring adjust and pre-load, below-roll-center weight addition on LR, differing oils, etc. I do prefer to use a mid-motor though to avoid the teeter-totter effect (rear motor lift to front wheels). I do attempt to drop the chassis as much as possible to keep the maximum weight below-roll-center as possible. Weight transfer is the key. This has just been my experience, but it could be a factor on different lengths and types of tracks.

[RC10th]

I built a short/long arm offset chassis car using DS on one side B3 on the other probably 10 odd years ago. The car came out great but I never ran it. Always wondered how well it would have worked, but according to the info here not very well. I love projects like this as the RC10 was an easy car to modify and make parts for, unlike todays cars.

Look foward to seeing your next project.