Propeller design .

This is a aerodynamic correct design, it isn´t a beautyfull propeller for 3D rendering, the objetive of this work is CNC machining a 80 inch diameter wooden propeller.

The start point of current propeller design is in my page: Designing, Drawing a classical (and for ever) wood propeller.

We going to modelate a propeller from only 3 cross sections, you can make more precise shape control with more cross sections. We going to use the Autocad propeller drawings from previous page. We only use 3 propeller sections, this sections have been streched to fit to correct chord/thickness dimensions and rotate to get correct pitch distribution along blade.

Starting with SolidWorks.

First, create 3 planes parallel to "front plane" with the create plane tool , in my design the first plan is 20% of prop radius, second is 70% and third is 100% (tip). You have to select front plane then click and specify "equidistance" from front-plane.

Next, select first plane and open a sketch , then, copy first airfoil (20% radius) from autocad and paste in solidworks sketch.
then, you have to coincide the gravity center to origin (there are a tool for get G.C. in Tools menu - Section properties).

Repeat with all sections.

Using Cover tool the airfoil secctions are transform into solid.

Next, Duplicate the first sketch to a "front-plane" and size it to 5 times the original size. Then use another time Cover tool to make blade root.

Cutting root blade to definitive shape.

Next, we draw a cut matrix based in Autocad propeller top view.

Repeat the same operation with lateral plane. This operation give the definitive shape of the blade.

The part is finished with a circular matrix operation . We have a beautiful propeller.