this is the blog entry for the powered launch dolly.

Starting from a toy RC car, I modified it into a motorized dolly.

the dolly is self powered , running from its own 3S LiPo battery , with a 20A brushed ESC, FrSky receiver.
There are two brushed motors wired in parallel, with gearing. Each motor drives one rear wheel. .
Aileron and rudder are mixed for the steering servo channel , so that dolly pilots may steer with the right and left sticks.
The Throttle is on the left stick.

here is the video of the first day launching the PZ Radian at the Bayside RC Club.

Motorized Dolly launch - Movie (0 min 29 sec)