Near as I can tell it supposed to be mounted in place of the thrust washer. to put it another way you have to remove the thust washer, slide the unit on, then tighten the thing with the supplied adapter nut. The adapter nut is tapped with 1/4-28 threads for the engine and 2.5 mm threads for the spinner tip (the red part). If you look at the front face of the machined portion (the face just forward of the prop blades) you'll see two, small set screws along the circumference. They are not turned in all the way, they protrude up about a 1/16" and are only used to aligned the forward, red plastic part of the spinner. From that same picture you can see two 3/16" holes, just under those holes are two pan-head allen set screws holding the prop hubs on. The prop blade shafts (about 1/4" dia., I'm sure they're metric but I couldn't get my calipers on them) are supported using ball-bearings/ thrust bearings.

The prop has a 11.4 in diameter, the spinner appears to be exactly 2.5" in diameter. According to what little paperwork was included the pitch is adjustable from 0" to 11.5"


If anybody would like more pictures from a specific angle let me know, I'd be happy to put them here for you to see.

Bill