The Ringmaster can't handle the Drone Diesel, it is 10 1/2oz. Now, ok it will only need 1 3/4 oz of fuel, but a PAW 15 diesel will pull it just fine and it is only 4 1/2oz. The Drone needs a ship like the CHIEF as it uses an 11x10 prop and is one rpm (~5800), the ships of the time for Drone's were too small at roughly 40" spans. It pulls a Guided Whistle (52" span) at 4.8 lap time on 60' C to C lines. It is tough to fit all the ignitions stuff on a Ringmaster even if you can get a light engine, still needs to carry an extra 3oz for coil, switch, ignition module and battery. Again, ignition ships tend to be larger to handle the extra weight.
Best, DennisT