R/C Tech Forums

R/C Tech Forums (https://www.rctech.net/forum/)
-   Electric On-Road (https://www.rctech.net/forum/electric-road-2/)
-   -   RWD, 4 Wheel Independent Susp. Onroad Cards - Why Not?, Why?, How? (https://www.rctech.net/forum/electric-road/979508-rwd-4-wheel-independent-susp-onroad-cards-why-not-why-how.html)

Hawk6 02-25-2017 01:14 PM

RWD, 4 Wheel Independent Susp. Onroad Cards - Why Not?, Why?, How?
 
The world of RC onroad cars is basically:
- 4wd independent suspension touring cars, or
- 2wd solid read axle pan cars, F1 cards
(Tamiya M chassis cars may be one of the few exceptions, they are 2wd and ind. susp.)

"Real" (full size) race cars are mostly 2wd + 4 wheel independent suspension:
- F1
- Indy
- LeMans
- sports car
- NASCAR
- etc.

Why the mismatch? Shouldn't there be more RC cars that are laid out similar to full size race cars?

I stumbled upon the Tamiya F103GT Nissan Launch car and thought it was pretty cool as far as body style. But, I just can't get excited about a 1/10 scale version of an exotic sports car where the 1/10 scale version is low tech solid axle, etc.

Shouldn't there be a RWD touring car chassis? Wouldn't that be cool for USVTA? Power slide around the corners in your '71 Cuda?

If I wanted to build one - other than not being able to race it in any recognized class - would it work? Could I just buy a touring car and take out the front wheel drive train?

Thoughts?

sgtlt 02-25-2017 01:40 PM

Should just be able to take out the front drive belt and front spool and axels, 4wd 1/10 off road buggys do it and they drive well just heavy compaired to a 2wd buggy

1spunspur 02-25-2017 03:12 PM

I've thought about this for many years. Even thought about combining off road suspension parts with on road parts. I couldn't come up with any thing to my liking and didn't have the tools to create a new chassis design.
Lately , I've been thinking of a TC4, gut the front tranny case & remove the front to rear shaft. And no, there is not a class for this but it would be fun to tool around with.

nicholasxuu 02-25-2017 03:13 PM

It would be expensive to design a competitive car for this never existed race class.

It would be hard to setup and hard to drive, 17.5t will feel like 600bhp touring car with no aerodynamic down-force. And, without a front-brake, a 600bhp touring car with only hand brake you can use.

And real race cars nowadays are also getting 4wd, top class in WEC (including lemans) is using 4wd hybrid cars.

*there are plenty of RWD drift cars matching your need though.

Hawk6 02-25-2017 03:33 PM

Thanks for the thoughts, all.

Here's a budget one:
Thunder Tiger TS2e Electric 2wd RTR Touring Car Review Big Squid RC ? News, Reviews, Videos, and More!


I guess my desire would be to have a race class with independent suspension all around and the ability to have cool prototype style bodies rather than racing 4 door sedan blobs (current touring car bodies).

http://www.bigsquidrc.com/wp-content...ring_car_9.jpg

Hawk6 02-25-2017 03:37 PM


Originally Posted by 1spunspur (Post 14849971)
I've thought about this for many years. Even thought about combining off road suspension parts with on road parts. I couldn't come up with any thing to my liking and didn't have the tools to create a new chassis design.
Lately , I've been thinking of a TC4, gut the front tranny case & remove the front to rear shaft. And no, there is not a class for this but it would be fun to tool around with.


Tamiya's website has their TA06 kit for $150. I'm thinking about buying one and doing what you said - remove front diff, dogbones, belts.

https://www.tamiyausa.com/images/pro...ry_TA06_01.jpg

Nice lay down shocks in front, so a sports car body should work on it.

sosidge 02-25-2017 03:54 PM


Originally Posted by Hawk6 (Post 14849990)
Tamiya's website has their TA06 kit for $150. I'm thinking about buying one and doing what you said - remove front diff, dogbones, belts.

https://www.tamiyausa.com/images/pro...ry_TA06_01.jpg

Nice lay down shocks in front, so a sports car body should work on it.

You'll find that a 4wd car handles very badly if you remove the front drivetrain.

If you want to get a rwd full suspension, rubber tyre car that actually handles, you've got quite a project ahead of you!

Hawk6 02-25-2017 04:06 PM


Originally Posted by sosidge (Post 14850005)
You'll find that a 4wd car handles very badly if you remove the front drivetrain.

If you want to get a rwd full suspension, rubber tyre car that actually handles, you've got quite a project ahead of you!

Why is that?
2wd = only rear wheels brake?

Or, weight distribution?

Or would need fatter tires in back to lay down the power (which would be OK).

All of the above? Something else?

Thanks.

ThePanda 02-26-2017 12:19 PM


Originally Posted by Hawk6 (Post 14850013)
Why is that?
2wd = only rear wheels brake?

Or, weight distribution?

Or would need fatter tires in back to lay down the power (which would be OK).

All of the above? Something else?

Thanks.

basically either tons of over or understeer, quite unpredictable, you have to be very careful on the brakes, and accelerate very moderately. they work with very mild brushless or brushed systems but anything fast doesn't really work.

fritzthecat 02-26-2017 12:40 PM

Drive an famiya m06 and you have an rwd car

Hawk6 02-26-2017 12:58 PM


Originally Posted by ThePanda (Post 14850833)
basically either tons of over or understeer, quite unpredictable, you have to be very careful on the brakes, and accelerate very moderately. they work with very mild brushless or brushed systems but anything fast doesn't really work.

Thanks for the info. So, sort of like a rwd Tamiya M series, or F103GT? Or, worse somehow?

Hawk6 02-26-2017 01:01 PM


Originally Posted by fritzthecat (Post 14850853)
Drive an famiya m06 and you have an rwd car

Does Tamiya have an M chassis body that looks similar to this?
http://www.mazdaraceway.com/sites/ma...ar-daytona.jpg

:D

Marcos.J 02-26-2017 01:01 PM

you also need to take in consideration the weight distribution of a real reace car and a scale car , not the same at all ,

i had a 1/8 on road nitro car years ago that broke a front belt and the car was very difficult to drive

fyrstormer 02-26-2017 01:04 PM

I've built a couple, with mid-rear and full-rear motor mounting positions, and they still handle like shit even with pro-compound tires. The basic fact of the matter is, touring car tires are too small to provide adequate acceleration and braking traction when only two of the tires are powered. Cornering is somewhat improved, which is why touring cars sometimes have optional one-way diffs for the front, so the front wheels can freewheel through easy corners while still providing traction for acceleration, but the tradeoff for using a one-way diff is that you get snap-oversteer if you use the brakes even slightly too hard. Combine the snap-oversteer of RWD braking with the endless wheelspin of RWD acceleration, and it becomes obvious that RWD touring cars are simply a waste of effort.

FWD, on the other hand, works brilliantly. While it still suffers from endless wheelspin on hard acceleration even if you use a cheap disposable brushed motor, the fact that the drive wheels are also the steerable wheels means that FWD touring cars corner like they're on rails. Furthermore, even though there are only two wheels providing braking, the fact that they're in the front means that the braking can be much stronger and more stable, with predictable understeer instead of snap-oversteer.

Here are a couple pictures of my first RWD touring car project:

http://i5.photobucket.com/albums/y18...l/IMG_0292.jpg

http://i5.photobucket.com/albums/y18...l/IMG_0288.jpg

Build thread here: http://www.rctech.net/forum/electric...a-rr-01-a.html

I eventually converted it back to 4WD, even though the motor is still in the rear, because it just handles better with four drive wheels. My other RWD touring car project has a mid-rear motor mount, and it's been mothballed because nothing I do seems to improve the snap-oversteer problem.

Hawk6 02-26-2017 01:48 PM

Thanks a bunch for the info. Very interesting.

I am looking at the Tamiya TA06, so maybe RWD, 4WBraking with a one way up front?

Maybe HPI 31mm wide rear tires would help?
https://images-na.ssl-images-amazon....SR238,320_.jpg

Plus, I am just thinking 17.5 or 21.5 or 25.5 motor.

It's fun to think about, at least. We'll see if I pursue it. Like you, I could always switch it back to 4wd.

Thanks again, I appreciate you taking the time to share your experience.


All times are GMT -7. It is currently 12:01 PM.

Powered By: vBulletin v3.9.3.4
Content © 2001-2011 RCTech.net