Alfa Model EDF 60/15 Mk.2 ducted fan is designed for the Speed 300/6V motor and/or for AC motors with similar performance characteristics ( MP Jet 25-25/26 Mk.2/Mk.3, MM 1215/12, Mega 16/7/4(3), Hacker B20 22S); the design velocity of flight is 15 m/s. The AC motors are better suited for the propulsion of the fan - their shaft is more solidly supported in the bearings and some are even dynamically balanced. Both these facts markedly influence the total performance of the fan; also their operational life is much longer than with the "Speed" type of the DC motor. The ducted fan can power models of the 500 grams maximum weight, whose wing area should be 12 to 15 dm2. The weight affects the flight performance of the ducted fan-propelled model much more than it does to a propeller-driven one, therefore it is advisable to save really every gram. The efficiency of the ducted fan is vitally dependent on both the accuracy of the assembly of the device itself, and on its correct installation into the model. Please devote therefore the maximum attention to the following information.