Some electric RC car advice

[Mark A]

What happens if you don't cut the comm?, does it slow it down?, as i have noticed my car goes slower after a few runs with a motor.

You seem to know what your talking about, would you say a 19t chameleon 2 will be a lot faster than a Tamiya Super Stock Motor Type RZ 23 turn @27,500 rpm?.

What do you mean by "gear it close"?.

Thanks


Mark

 

[Berger]

When i say the gearing being close i mean your not massively over or undergearing it.

If you overgear it, the acceleration will be pretty slow but you will have increased top end, but it will tend to bog down a bit at slower speeds and overheat the motor.

If the motor is undergeared, it will be screaming its head off at max RPM as it will have bags of acceleration but run out of steam pretty quick, this will also cause it to heat up a lot.

At first the comm is a nice shiny copper colour, as you use it, it will become blackened and wear down at an exponential rate due to the brushes wearing it while running, causing a very slight loss in performance each run. Excessive wear can start to cause interference and will also lead to premature death of your motor in some cases, so you need to keep it looked after!

 

[Mark A]

Thanks for the help Berger. So its a case of trying different gears untill your motor doesn't get red hot?. Ive got 3 spur gears and quite a few pinion gears so it'll take a while trying them all.

Could i not just clean the comm with brasso every now and again?.

Id value your opinion on weather i should get a 19t to replace my 23t RZ.

Mark

 

[Berger]

If your happy with how it runs now i wouldnt swap, but if you change from a 23T to a 19T you will gain some acceleration and top speed, at the expense of runtime.

The cameleon 2 isnt a bad motor, its been around for a while now but can run a little hotter than some! Ive not tried the komodo dragon myself as its not a legal motor to run in most race series due to its makeup (few minor internal differences) but i believe it gives more power through the whole range as well as running a little cooler.

You will want to use a pinion gear a tooth or two smaller than what you currently use with your 23T motor, cant give an exact figure as some motors produce more torque or rpm than others so are geared differently, but thats a general rule.

Over 5 minutes i gear my motors so that they top out about 3/4 of the distance down the main straight, and after 5 minutes i can put my thumb on them for around 3 seconds before it starts to burn

As for cleaning the comm with brasso, the main problem is that as it wears it becomes out of round, with each "segment" wearing down on the trailing edge, so the comm is cut not only to give some fresh clean metal, but to ensure it is perfectly round again hence a lathe is needed.

 

[Mark A]

Thanks Burger, you've been a great help .