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Old 10-16-2018, 12:34 PM
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Default All Wheel Steering for On-Road

I am competing in an event where the track is very small. It is only 4 feet wide and the whole track is quite compact with hairpin turns. I am new to RC, so I bought the cheapest 1/10th scale touring car I could find (The Trunigy TD10 V2), but even with the wheels locked out it has a 2.5 ft turning radius, which makes the hairpins really unforgiving (the center-line on these turns is a 2ft radius!). Two questions:
  1. Is there any on-road kit that comes with all-wheel steering standard? Or is there a kit that is easy to modify?
  2. Do you think this will make a noticeable difference in these tight turns?

Last edited by ThunderNeed; 10-16-2018 at 12:55 PM.
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Old 10-16-2018, 01:24 PM
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Try contacting wtcc i think he try 4ws on one of his car
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Old 10-16-2018, 01:30 PM
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No kits come with 4ws as standard. Touring cars that is. Several could be reasonably easily modified for it. Any kit that has a "dynamic rear toe" kit, or setup, could be modified.

Now.. lets talk about "how big of a problem" this is. What you're running in to, is that at slow speeds, your turning circle is defined by the speed at which you can swing the front of the car around the center of the rear wheels. This only holds true at the slowest of speeds. As your speed picks up, and tires start to act.. dynamically? Well as soon as they start generating real grip, they start sliding. Your cars center of rotation moves forward from between the rear wheels, and starts to approach the front wheels. The ultimate extension of this, is doing donuts.

So there are things you can do, to encourage chassis rotation. Stiffening up the rear diff will help. At least, that's where I'd start. So would loosening up the front (EG: putting a diff up front, instead of a spool..)

The TD10 v2 also has some shims in the suspension IIRC, so you can shorten up the wheelbase a little.
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Old 10-16-2018, 01:46 PM
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Originally Posted by Nerobro View Post
So there are things you can do, to encourage chassis rotation. Stiffening up the rear diff will help. At least, that's where I'd start. So would loosening up the front (EG: putting a diff up front, instead of a spool..)
Is "encouraging chassis rotation" the same thing as encouraging oversteer? I am kind of new to RC; not sure if these concepts are related.
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Old 10-16-2018, 01:49 PM
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I had a tiny track in my basement not long ago where the lap time might be 4-5 seconds (didn't have a lap timer). Lane width was small as well. I would race my Mini's and my TC down there. Like mentioned by Nerobro a lot of chassis tweaks can help get the car to rotate a lot more and do what you need. The biggest question off the bat, does the car have a front spool? If so put a gear diff in it. I ran my TA06 with a gear diff vs my Cousins T4 at the time with a spool and there was a huuuge difference as far as turning radius. I got the Spool to work by rotating the rear of the car pretty good..no set up change just driving style and using the brake.

Post a pic of the track?

Some things to consider maybe..

-Front gear diff
-Shorter wheel base
-Less front droop
-More rear droop
- +1mm or even 1.5mm bumpsteer shim
-Move the shocks more inboard on the rear
-Thinner shock fluid for less pack and more transition
-Less rear toe

probably some others for sure but off the top of my head..
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Old 10-16-2018, 01:51 PM
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Originally Posted by ThunderNeed View Post
Is "encouraging chassis rotation" the same thing as encouraging oversteer? I am kind of new to RC; not sure if these concepts are related.
Imo not exactly, when you have good rotation the car is still planted and good drive. If you have big oversteer or snap over steer that's a big un settling feeling while driving the car
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Old 10-16-2018, 02:00 PM
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I build a 4ws car some years ago. It was not easy to drive, but if got the timing right fast laptimes were possible. However tight lines are not the strength of a 4ws car like I built it, because rear will move to the outside when you start to steer. And that is a strange feeling and look. The only positive way to use a 4ws would be if the rear starts to steer later, maybe from the middle of the turn or a little bit earlier. But that would also be a little awkward...
So I think it is better to rely on 2ws and a car balance that forces the rear into a light drift.

That is the old thread: https://www.rctech.net/forum/electri...2-tc6-4ws.html
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Old 10-16-2018, 02:01 PM
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DaSilva,

Regarding the front diff, the stock setup is a spool. They don't sell a front diff for this model, so I assume i just buy a back diff and install it up front.

Regarding the course, they actually re-make it every time we race by laying tape down on a concrete or carpet floor depending on where we are meeting. Much of the course is pretty relaxed, but there must be at least one hairpin. The event is diyrobocars.com, these cars are using cameras + software to drive with no human input. Search YouTube for "OpenMV head-to-head race at DIY Robocars meetup" to see a video of one of the tracks from a few months ago. I would post a direct link but it says my account is too new.
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Old 10-16-2018, 02:09 PM
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I see I see.... The diff from the rear usually doesn't work on the front (I may be wrong here but Im 90% sure most TC models are not inter changeable from front to rear vice versa) The front Diff is single handedly one of the biggest changes you can make on a tight course I feel. Tweak the rest of the car to the best of abilities and see what happens
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Old 10-16-2018, 10:13 PM
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Originally Posted by ThunderNeed View Post
I am competing in an event where the track is very small. It is only 4 feet wide and the whole track is quite compact with hairpin turns. I am new to RC, so I bought the cheapest 1/10th scale touring car I could find (The Trunigy TD10 V2), but even with the wheels locked out it has a 2.5 ft turning radius, which makes the hairpins really unforgiving (the center-line on these turns is a 2ft radius!). Two questions:
  1. Is there any on-road kit that comes with all-wheel steering standard? Or is there a kit that is easy to modify?
  2. Do you think this will make a noticeable difference in these tight turns?
How are the other drivers taking the turns? Are they all driving non-conventional touring cars?

FYI - XRay diffs fit both front and rear with no changes, and I suspect your Turnigy is a clone of XRay
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Old 10-16-2018, 10:22 PM
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I found the video.














After watching the video, I’ve got a question. Are you driving or is this some kind of A.I challenge. Might help with suggestions.
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Old 10-16-2018, 11:38 PM
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Originally Posted by belewis01 View Post
How are the other drivers taking the turns? Are they all driving non-conventional touring cars?

FYI - XRay diffs fit both front and rear with no changes, and I suspect your Turnigy is a clone of XRay
The turnigy is a Sakura. The spool and diffs are exchangable.

Until the latest generation of cars, most diffs and spools have been universal. My TT02, TT01, TC4, Sakura XI, Turnigy TD10, TA07, among others... have symetrical diffs/spools.
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Old 10-16-2018, 11:49 PM
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Originally Posted by ThunderNeed View Post
Is "encouraging chassis rotation" the same thing as encouraging oversteer? I am kind of new to RC; not sure if these concepts are related.
At the extreme, yes, it is. "Oversteer" is what happens when things get out of control.
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Old 10-17-2018, 09:47 AM
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learn to crack the rear end loose using the throttle in a turn. brake entering and at the apex give it power the rear will cut loose for RWD.
you can also stiffen the rear suspension and soften the front to increase steering.
use harder compound rear tires again to increase front steering.
set the front tires to Toe-out to give more initial steering.
reduce rear toe-in to encourage the rear to get loose or use rear toe out, you will loose straight line stability.
etc...
you don't need 4ws for onroad.

if this is one of those robot competitions then you want a very short wheel base chassis.
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Old 10-18-2018, 09:10 AM
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@Billy Kelly
Yes this is an autonomous racing challenge. The main challenge is making software/AI that is any good. Right now the best techniques use something called "behavioral cloning". The way it works is that the human drives 10-20 laps as best they can while the computer records everything (the commands the human sent, the images the car-mounted camera took). After those training laps an artificial intelligence algorithm is used to analyize those 20 laps and tries to copy the driving style of the human. Then the car drives controlling itself, usually much worse than the human.

@Tamiyadan
Do you have any suggestions for a SWB rc car? Googling does not provide many results. The Sakura Ultmate has a front track width of 163mm and a wheelbase of 257mm. If I were to make a bunch of custom parts I might be able to get the wheelbase down to 247mm, but thats a lot of work.
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Last edited by ThunderNeed; 10-18-2018 at 09:24 AM.
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