Razor Rotor blades rip up Bloons on contact, including Lead and Frozen Bloons.
~ BTD6 description
Razor Rotors is the third upgrade on the first path for the Heli Pilot. It allows the Heli Pilot's blades to hit bloons on contact, popping them. It can also pop Lead Bloons and Frozen Bloons. Razor Rotors have TBA pierce per cycle in BTD5, and 10 pierce per cycle in BTD6. It costs $1485 on Easy, $1750 on Medium, $1890 on Hard, and $2100 on Impoppable in BTD5 and BTD6.
Razor Rotors is best used when not in Pursuit Mode. Instead, it is better off to micromanage the Heli Pilot by manually flying the Heli Pilot over the target bloons, especially Lead Bloons.
Especially in the case of BTDB Mobile (but also in BMC Mobile and BTD5 Mobile), the Razor Rotors attacks usually misses bloons while the Heli Pilot is on Pursuit Mode, because the Heli Pilot generally flies beside the track.
In BTD6, Pursuit Mode is not nearly as negative when paired with Razor Rotors. The Heli Pilot on Pursuit Mode will now only follow just in front of the bloons.