RE: GP Viper + TT .46pro
The GP Viper with the TT .46 Pro will probably be in about the 120 to 125 mph range. Put a 9X7 or 9X8 APC prop on it and you'll have a fun and fast sport plane. It will be faster than the Skyraider. You might want to experiment some with the APC pylon props--8.75 and 8.8 inches in diameter with various pitches from light to heavy.
Good luck and have fun!