The short answer is here is to re-direct your dogs attention away from the RC car. How is the down stay command???
I would work that command until it is rock solid for a good 30minutes without the dog breaking with heavy distractions, (people, balls being thrown around, noise makers, etc). Once that is accomplished, I would start with the RC car way down the street but still visible to the dog, and work the commands. Then SLOWLY bring the car closer and wait for the dog to break and when it does correct him (with a buckle type collar if feasible) and put him back. Bottom line is get the dog to pay attention to you rather than the distractions. If your dog shows fear in other situations build confidence by working those OB commands in public (I like to use my local Petsmart) and maybe have other stimuli around when you practice. When your dog pays more attention to you than the distractions, you win...
Or you could just give a nice big prime rib while playing with your car....;f
Don't be too harsh on the corrections and be very heavy on the praise and his confidence will come around...;c
Did you pet your dog today?
Proud owner of Black rifles and Assault Canines !!!