You can use the state system and stuff to make it fire projectiles/raycasts down when you aren't using it, until it hits a brick with a "fire" emitter (Fire A, Fire B, Jeep Fire, Player Jet) and then set on fire.
I could make a version of this using the Stick model from RTB (or if someone provides a replacement). It wouldn't create much lag - it would use raycasts and states like my Gravity Gun which only "lags behind" if lots of people are in the server and almost never creates a LAG sign.