APC Slow-Fly Electric Series props offer high thrust at low RPM, and offer great value for your electric powered models. The Slow Fly Pusher Series are designed to be used in matched pairs with twin engine models, or for use on the new Quad-Rotor models that are becoming so popular. The center hole of the prop is designed to accept a reducing bushing to fit your propeller shaft. Included with the prop are 2 bushings to fit 3/16" and 6mm prop shafts.
According to the widely accepted Maximum RPM formula of 65,000/D for APC SF-Series props, the 10x4.7SF pusher prop should not be used over 6500 RPM.
What is the inner diameter of the propeller without bushings?
Question by: Evan Kaufman on Jul 18, 2016 1:09:00 PM
The hole in the center of an APC 10x4.7-SF prop, on the front side, is 1/4 inch (6.35mm). This is a non-precision hole that is drilled to remove the sprue left over from the injection molding process, and is not guaranteed to be perfectly centered on the prop hub.
The back side of the prop has a molded recess, which is precisely located in the center of the prop hub, and is designed to accept the centering rings that come with the prop. This recessed area is 8.0mm in diameter, and is 2.6mm deep.
The prop ships with two adapter rings, and both of them have an outside diameter of 8mm to fit into the recess on the back side of the prop. One of the adapter rings has an inside diameter of 3/16 or 0.188 inches. This is equal to 4.8mm, and if the prop is used on a motor with a 5mm threaded shaft, you will need to drill the center of this ring out to 5mm after it is glued into the back of the prop.
The other adapter ring has an inside diameter of 6.0mm (0.236 inches) and is designed for motors that have a 6mm threaded shaft.