Driving Realistically

[Herr Dr. Professor]

I am a fortunate fellow whose retirement income is modest, but supports hobby addictions. So now I have too many AVFs and soft targets (viewtopic.php?f=33&t=30720&p=299937#p299937) to even start swapping out motors and/or gearboxes. Yet every one of them runs faster than I would prefer. In fact, my Schnauzer thinks the RC Tamiya Kubelwagen is a mouse!
I have always wondered if one could solder in the leads from the control board to the motors some kind of resistor to slow motors. There must be some reason that idea would not work. What is it?

[abramsky]

The reason why nobody does that is that on motors larger than the 130 type this may require resistors of adequate wattage to withstand the current and heat dissipation. It is enough that at a voltage of 8.4V current flow to motors with an intensity of 10A. That's 84W (watts) in total. Resistors that can withstand this amount of power are large and require radiators because they generate a lot of heat
See what such a resistor could look like:

It is quite large and requires mounting on a metal housing to better dissipate heat.

In addition, the voltage drop across the resistors will unnecessarily burden the battery (it will shorten the time to play with the model).
It is much easier to use an engine with the appropriate RPM and torque.

[Will01Capri]

No need to use resistors for slowing motors, plus its boot efficient.
Most controllers these days have programmable settings so you can reduce limits or change throttle curves. Also no reason full throttle position needs to be used if the appropriate gearing and torque motors are used.
I use a many different industrial spec geared motors in all my models, but even still come into difficulty with gearing so sometimes make simple 2gear gearboxes. I also tend to try and spec a battery and motor setup much larger than is needed so I can tune the controllers so even if I reduce throttle to 50% for example it still has enough torque to slowly pull away
I think the motor I use in the Kubelwagen is far bigger than it needs to be, but it gives a good balance of speed and slow control, so realistic driving can be achieved

[Jimster]

Exactly how my Kubel is controlled. Very drivable and most enjoyably engineered,Will and Catherine!
I consider this a great example of why everyone should get a good programmable radio right now with OpenTx installed. That would solve almost all control problems. If I could go back in time two years I would tell myself that exact thing.
I will now step down from my soapbox.

[Herr Dr. Professor]

Hmm... Hot resistors: just what I suspected... ( I once knew her.) Thanks, abramsky, for the great explanation with URL!

Jimster, about six years ago, I had a good transmitter, Turnigy I think, but got all confused and sold it to a fellow who had long experience with RC car racing. Still, I will reconsider. If one of you wizards were nearby we would have a post-Covid club (there will be a post-Covid world, right?). Then I could sponge knowledge and skill off of you.

Ahem: In part my problem is too many hobbies: besides RC Tanks, etc., there are farm toys, O Gauge railroading, 1/48 airplanes, 1/35 AFVs and etc., 1/18 AFVs, aircraft, books about all of the above... Doncha feel sorry for me?

[Estnische]

Nope! I’ve also got a motorbike, bass guitar and slot cars, and I still work. Seems like I can’t do all of them properly.

[Jay-Em]

Which gear box for the Igarashi?

Short answer : Any.

Longer : Whichever is the nicest..

I use them in every ‘old tank’ gearbox, plùs in my Kyosho blizzard. Oh, and in a Thunder Tiger 1/12 crawler.