RWD M-Chassis, 1/12th inspired
#1
RWD M-Chassis, 1/12th inspired
To brighten up my local track in Dagmersellen (CH) with some self made stuff I decided to give the M-chassis class a go.
First Pan-M concept sketch and space allocation.
The differences to a Tamiya M08 are not overly crazy.
Yes, it's more of a pan car than a touring car. But hey, some mix and match should be allowed!
Basic Idea
- Compete with M-Class guys (much more experienced than me) with a home built chassis
- Keep the same tyres, motor top speed, wheel distances and bodies as all others
But capitalize on the fact that it's a home build
- Chassis should be simpler, lighter and more robust, but adaptable enough to tune to my driving style
The current working plan is:
- Buy Pan car chassis
- Adapt wheelbase, track width and ride height
- make new wheel adapters
- make new bumper and body mounts
- use sweep or rush rubber tyres and M chassis body
Anybody got thoughts or recommendations?
First Pan-M concept sketch and space allocation.
The differences to a Tamiya M08 are not overly crazy.
Yes, it's more of a pan car than a touring car. But hey, some mix and match should be allowed!
Basic Idea
- Compete with M-Class guys (much more experienced than me) with a home built chassis
- Keep the same tyres, motor top speed, wheel distances and bodies as all others
But capitalize on the fact that it's a home build
- Chassis should be simpler, lighter and more robust, but adaptable enough to tune to my driving style
The current working plan is:
- Buy Pan car chassis
- Adapt wheelbase, track width and ride height
- make new wheel adapters
- make new bumper and body mounts
- use sweep or rush rubber tyres and M chassis body
Anybody got thoughts or recommendations?
Last edited by h2e; 11-27-2022 at 10:30 PM.
#2
It'll be fun
To brighten up the local track with some self made stuff I decided to give the M-chassis class a go.
first Pan-M concept sketch and space allocation.
The idea is as follows:
- Buy Pan car chassis
- Adapt wheelbase, track width and ride height
- make new wheel hexes
- make new bumper and body mounts
- use sweep or rush rubber tyres and M chassis body
Anybody got thoughts or recommendations?
first Pan-M concept sketch and space allocation.
The idea is as follows:
- Buy Pan car chassis
- Adapt wheelbase, track width and ride height
- make new wheel hexes
- make new bumper and body mounts
- use sweep or rush rubber tyres and M chassis body
Anybody got thoughts or recommendations?
Have fun!
p.s. lowest possible roll centre is best
#3
Thanks for your remarks. Found the GT500 already. Looking for the Kawada... Thinking about using V-Link or single joint. Especially as I will move the ride height to 5mm (that's what the M guys have to run).
- Single joint has the advantage of simplicity and less play
- v-links give all freedom...
what to choose?
- Single joint has the advantage of simplicity and less play
- v-links give all freedom...
what to choose?
#5
As my body choices are all RWD with the MX-5 (Tamiya, 225mm), Seven20 (Bitty, 201mm) and Porsche 911 (Supastox, 201mm), I will try to have a chassis wheelbase between 200 and 225mm. And as it is an indoor fun thing, I hope that my bump capability will be good enough. For outdoor I will try and see in the future.
As for the TCR-M, I like that chassis for its versatility and corner design that allows for crazy servo, motor or battery positions. I don't particularly like the limited tuneability of that chassis. Or what levers do you think one has for tuning under- and oversteer in corner entry/exit? And to change gearing you need to buy an alu motor mount? What about the outdrives? They don't have blades or ball bearings, so wear will be worse after a few hits?
For the Pan-car chassis I see caster (initial steering, exit steering), pod damping (reaction in chicane), droop (off power behaviour), gear diff oil or spool. I see super durability for impacts, and virtually no drivetrain wear (if I protect the rear axle from impacts via carbon bumper plates).
Am I missing something, or can you speak of experience with the TCR-M that it is a more versatile chassis that one might think?
#8
Thanks for the tip. Looks like it's not made for 5mm ride height. The front wheelhub looks interesting and I might copy that. The T bar looks not adjustable though. Maybe it needs a bit more refinement.
After reading about rc chassis dynamics I decided to allow for a v-link rear pod, because with the 5mm ride height I might mess up with the antisquat with just a normal ballcup/ballhead link.
Also it looks like I will have an issue with steering Ackermann... lets see how that can be solved.
After reading about rc chassis dynamics I decided to allow for a v-link rear pod, because with the 5mm ride height I might mess up with the antisquat with just a normal ballcup/ballhead link.
Also it looks like I will have an issue with steering Ackermann... lets see how that can be solved.
#9
Tech Champion
iTrader: (2)
Thanks for the tip. Looks like it's not made for 5mm ride height. The front wheelhub looks interesting and I might copy that. The T bar looks not adjustable though. Maybe it needs a bit more refinement.
After reading about rc chassis dynamics I decided to allow for a v-link rear pod, because with the 5mm ride height I might mess up with the antisquat with just a normal ballcup/ballhead link.
Also it looks like I will have an issue with steering Ackermann... lets see how that can be solved.
After reading about rc chassis dynamics I decided to allow for a v-link rear pod, because with the 5mm ride height I might mess up with the antisquat with just a normal ballcup/ballhead link.
Also it looks like I will have an issue with steering Ackermann... lets see how that can be solved.
http://www.kawadamodel.co.jp/manual_...anual_m333.pdf
#10
TCR-M is really a beast. I've tried to perform some modifications on the TCR, but TCR-M was already so agile out of the box, I had nothing to change: https://photos.app.goo.gl/cFFXQShSfGMBqA579
That said, I've tried the TCR in MR motor position instead of FF, and it is waaaaaaay slower...
That said, I've tried the TCR in MR motor position instead of FF, and it is waaaaaaay slower...
#11
Well the TCR-M may definitely be a plan B if my already purchased base car plus my mods show to be slow.
I want it rear mid motor as my Bodies will be rwd cars. Don't want to spoil it all too much this time...
The rear pod on pan cars seems to create way too much anti squat (typical >200%, my M-class prototype: 166%), so I am thinking of making a 3 link rear pod attachment like the "Pantoura" that can be found on rctech too, to create less anti squat.
typical anti squat geometry on pan cars (centre ball and two side links).
Where I am unsure is what front wheel suspension I should choose, and where the rollcenters should be lying. Many rollcenter decisions on pan cars seem to exist just to counteract other weird effects (foam tyres hooking suddenly etc.). As I will run M chassis rubbers the starting point may as well be completely different.
I want it rear mid motor as my Bodies will be rwd cars. Don't want to spoil it all too much this time...
The rear pod on pan cars seems to create way too much anti squat (typical >200%, my M-class prototype: 166%), so I am thinking of making a 3 link rear pod attachment like the "Pantoura" that can be found on rctech too, to create less anti squat.
typical anti squat geometry on pan cars (centre ball and two side links).
Where I am unsure is what front wheel suspension I should choose, and where the rollcenters should be lying. Many rollcenter decisions on pan cars seem to exist just to counteract other weird effects (foam tyres hooking suddenly etc.). As I will run M chassis rubbers the starting point may as well be completely different.
Last edited by h2e; 11-18-2022 at 01:30 PM.
#13
#14
No minimal weight? TCR-M will dominate that without even breathing lol.
17.5 with a TS50 and a 3800 LCG shorty lipo, you should be around 800g with a light body lol
17.5 with a TS50 and a 3800 LCG shorty lipo, you should be around 800g with a light body lol
#15
That's exactly what I am aiming at. but don't tell anyone.
Unfortunately it's going to cost dearly to mod a 1/12 car, as the front wheels need to fit a 12mm hex. So I will need to use 1/10th steering knuckles, and so a full blown front suspension. So weight wise I might go to 900g.
Unfortunately it's going to cost dearly to mod a 1/12 car, as the front wheels need to fit a 12mm hex. So I will need to use 1/10th steering knuckles, and so a full blown front suspension. So weight wise I might go to 900g.