Originally Posted by losifanatic
The 250 is based on a 250 sized brushless motor, the 400 is based on a 400 sized brushless motor, the 450 has a 450 size motor, and a 500 has a 500 size motor.
They sized by there motor
The 1st 3 are correct 250, 400 and 450 were all originally based on motor size, however the 500, 550, 600 and 700 heli's are all based on blade size.
The mini Titan 325, is based on blade size which makes it the same size as a trex 450!!