I live on the third floor, and have a balcony overlooking the gardens.

I want two Remote Controlled cars that I can race on the concrete/short grass below

Both of the same sort preferably

But everything seems to be helicoptors these days...

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If you want to control from the balcony, then range might be an issue. a decent transmitter might have a reliable 100M range, in idea conditions. But, if you're thinking about a car from a toy store, I wouldn't bet on it.

Electric will have limited battery life, and power. especially on grass. Without a battery-destroying fast-charger, you'll spend hours recharging for less than 15 minutes of driving, probably.
IC is where it's at. You get power, speed, and highly flammable fuel. You probably won't be allowed to legally store the fuel anywhere (nitromethane and methanol), and the noise of the cars will probably piss off your neighbours.

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Im not too fussed about batterly life, ill only use them for a short time before i get bored

But yes, Range does seem to be the biggest problem, looking at about 20m range. And R/C cars dont seem to be popular round here

I'm tempted by the Battling Helicoptors, but I dont think they will survive too many 10m falls to concrete...

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you wanna have rc cars 20 m on the concrete below, let me know when so i can stick them in the motor

You'll never catch them, remember your Wii Fit score?

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Those pico copters are great fun in the office, but wouldn't fly one outdoors.
They can take quite a beating though, mostly foam plastic.

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