B-25 Mitchell 3-blade Propeller | STL Files for 3D Printing There are 6 .STL files in total, compressed into a .zip file.
These are the STL files I made to get a realistic looking display propeller for a B-25 Mitchell Bomber r/c model airplane. The propeller is about 1/12 scale and has a diameter of 13 inches. This propeller is for display purposes only, do not turn this propeller with an electric motor! This propeller's only purpose is to make the airplane look pretty, never to fly it.
The purple propeller blades for the model in the pictures were printed vertically, the black blades on the completed propeller were printed horizontally. STL files for printing the blades both horizontally and vertically are included. The blade is much stronger when printed horizontally because the "grain" or printing layers extend the entire length of the blade. However the leading and trailing edge detail is rougher. When the blade is printed vertically the shape and detail of the blade is wonderful, but just like a wood blade whose grain goes from leading edge to trailing edge the vertical print blade snaps easier.
For each individual propeller there are six basic parts, one hub dome, two parts for the hub and three parts for the blades. The hub needs three #2 x 1/2" socket head sheet metal screws to be assembled. The three propeller blade roots are captured inside of the assembled hub. The B-25 Mitchell Bomber requires two propellers.
The 3D printed parts will need processing after printing. I found 60 grit and 100 grit sandpaper or equivalent, plus a small metal file to be essential. It is also handy to have a set of small drills and a Dremel tool. Make sure all the parts fit properly before starting on the gluing or finishing.
Use Bondo Glazing Putty to fill and smooth parts. Mask off the propeller roots and the inside of the hub front before primer and painting. There are some good pictures of this process in the F6F Hellcat propeller ad.
Materials needed to complete each B-25 Mitchell Bomber Propeller: 3D printer with filament and a 7 x 7 inch print bed with 6.5 inches vertical or Z-axis capability (for vertical printed blade), (3) #2 x 1/2 inch socket head sheet metal screws, Bondo Glazing Putty, 60 grit and 100 grit sandpaper or equivalent, primer and paint.
This is an order for STL files to 3D print unlimited number of B-25 Mitchell Bomber 3-blade Propeller parts for your own personal use ONLY. Please don't give away or resell the files.