RC12E With Brushless?

[jvulich]

I have a pair of RC12E cars that my dad raced from 1979 to 1981. They were modifed, tweaked and upgraded as he kept them competitive for the local race circuit. I'm in the process of cleaning them up after all of these years of storage and I'm thinking about swapping in a brushless motor, a modern radio and a lipo battery into one of the cars that no longer works. Has anybody done this? Keep in mind that I'll be making a new radio tray and original parts will be kept should I choose to change it back.

[RC10resto]

Do you have a track to run them on?
If not, you may want to hold off and try one with a brushed motor and a standard battery. These cars are very light and quick and "almost" undriveable in stock form on the street.

[Coelacanth]

That could probably be done but that chassis would present several design challenges. The two-deck design might not permit a 1S LiPo battery to fit between them. A 1S LiPo requires a special ESC that can work with a low-voltage battery, as most ESCs have too high of a low-voltage cutoff function and thus won't even work unless they detect at least 5 volts minimum. Physically mounting the ESC, a tiny modern receiver & servo is the easy part. Depending on the brushless motor, most modern motor cans are somewhat longer than brushless ones; they'll probably fit in the pod but will off-center the weight and you'll need to counterbalance it to avoid chassis tweak.

I did all that with an RC12L3 chassis, which is probably easier to do, but still required a good deal of modding and re-engineering to make modern electronics and even a small 1S LiPo fit where 5 or 6 cells are meant to fit instead. You can check it out here and weigh your options (pun not intended); it might not be worth the cost and effort.

http://www.rc10talk.com/viewtopic.php?f=37&t=35541

[jvulich]

I do have access to a couple of tracks at a local hobby shop to run it at. A couple of guys that I work with are building drift cars with a brushless and 2s 7.4 volt lipo batteries that look no bigger than the closed bell 540 Reedy modified and the sanyo battery pack that are currently in it.

[Coelacanth]

2S LiPo is a lot of power for a 1/12 pan car. They're basically like a 7-cell 8.4V battery when charged up, not like a 7.4V 6-cell battery from back in the day. Just sayin'.

[Phin]

Even with modern power an RC12E isn't going to be a competitive car so I say don't bother and just stick with a brushed system. You can still use lipo's for the longer run times but you'll need a low voltage cutoff unit for your old ESC or buy a dirt cheap modern brushed esc that's already set-up for lipo.

[jvulich]

I'm not trying to build a competitive car, just something that to have fun with and get that WTF factor when I pop the body off at the track. Phin, this car currently does not have an esc, it has a resistor that only works at full speed.

[Coelacanth]

I didn't build mine to be racing/competitive either, just to perform well enough as a fun driver. But on 2S LiPo power, the thing would be impossible to drive controllably, at least with a 17.5T motor (and my racing skillz/lack thereof). Some people suggested in my thread to go with a 380-size motor instead, to cut down on the speed with 2S LiPo. If you insist on going with a 2-cell LiPo, you might look into that possibility.

[Phin]

I'm not trying to build a competitive car, just something that to have fun with and get that WTF factor when I pop the body off at the track. Phin, this car currently does not have an esc, it has a resistor that only works at full speed.

Cheap Chinese brushed ESC, that will operate on both nimh and lipo, can be found on eBay for around $10 US.


There's a few issues I think you're going to have with a brushless in a 12e.... first being pod space. Modern cars have wider pods and longer motor plates than the 12e did. While the width of the 12e pod might be okay, the short motor plate is going to make gearing a brushless motor a problem. Brushless 1/12 pan cars run a large pinion and a small spur and the 12e might not have the space to mount the motor far enough from the axle for those kinds of gears.

Related to gearing, the next issue is the fixed rear axle height on the 12e. Modern 12th cars run very short diameter tires to adjust rollout. A shorter tire requires a lowered rear axle to maintain ride height and again you can't do that on a 12e.

Last, but not least, the whole 12e's chassis design is the polar opposite of how modern 1/12 pan car chassis are designed.

Modern electronics, batteries, and motors are lighter and more powerful so new chassis are made heavier and stiffer to help increase traction and put the power to the carpet. The 12e's suspension is mostly chassis flex and it's built super light because the other components were heavy, the motors weren't as fast, and the batteries didn't last as long.


So, basically, while you can probably fit a brushless system in a 12e, and run the car with it, the 12e is not going to get all the power out of the modern gear or be significantly faster than a cheaper brushed motor.

[jvulich]

For this particular car I'm deciding to stay with a brushed setup. I've got an extra E pan with a sprung 12L front end on it that I might try going brushless on in the near future.

[jvulich]

I ended up removing the complete original RC12E radio plate and making a new one out of white styrene. I also removed the Reedy Modified motor that's been in it since 1980 and put it away as well. I installed a new metal gear servo, 13 turn modifed brushed motor, and a 320 amp brushed esc. At this point I'm waiting for my 3300 mah lipo battery to show up so I can finalize the placement of the esc.