EDF Unit Common Sizes
There are only a small number of the most popular sizes for Electric Ducted Fan Jets. The size of the fan to be used is best selected by the size and weight of the Jet. It’s quite simple, larger jets will require large fan units. Fan units range in size and are listed by the nominal size of the fan diameter. Fans are best selected by knowing the approximate RTF (Ready to Fly) weight of the plane.
56mm Ducted Fan – Best used in planes that weigh less than 1.75 pounds. Common motor diameter for this size of fan is 24mm.
70mm Ducted Fan – For planes ranging in weight from 2 to 5.5 pounds. Common motor diameter for this size of fan is 28mm.
90mm Ducted Fan – Best Used for planes ranging in weight from 4.5 to 10 pounds. Common motor diameter is 36mm.
120MM Ducted Fan – For planes ranging in weight greater than 8 pounds. Common motor diameter is 39mm or larger.
Most planes when purchased are setup to run only one size of fan. This further simplifies things as it would be best to select the recommended fan for fitment and power reasons.
EDF Blade Count
A typical electric ducted fan unit may contain anywhere from 5-13 blades. The number of blades would affect the running speed of the motor, and sound quality. A high pitched scream is very common with EDF units using a smaller number of blades. The smaller number of blades requires higher motor RPM’s. A larger number of blades up or over around 9 would require a motor spinning at lower RPM’s when compared with an EDF unit of a smaller number of blades. The higher amount of blades would also change the sound of the fan. It is common for higher number of blades in an edf unit to provide more of a scale type woosh sound. As electric ducted fan jets increase in popularity, more and more people are opting for the higher blade count units for that scale like sound.