When showing off a static model at a contest, the first thing a judge sees is the propeller on your model, so it had better be a knockout! Making what I call a “show propeller” is not difficult and it only takes a short time to carve out a masterpiece to install on your airplane.
The tools needed to make the propeller are usually in the shop (Photo 1). A band saw is also needed to cut out the outline of the propeller and a circular saw is used to cut the pieces of redwood and pine to make the propeller blank pieces.
If you are a modeler in need of a beautiful propeller, read on and let’s make one. I will describe how to make a 24-inch laminated propeller for use on a 1/4-scale Travel Air biplane.
Making the Blank
Go to the lumberyard and select two 6-foot pieces of 1 x 4-inch wood—one redwood and the other pine. Select the wood carefully and find lightweight, straight-grained wood without knots or other imperfections. Cut the stock into 2-foot lengths then, using the circular saw, rip the pieces into 3/16-inch strips.
If you have a belt sander, sand all of the wood pieces, but this step is not always necessary. Now, pick out your best pieces of wood—three pieces of redwood and four pieces of pine needed. The blank should be put together as shown in Photo 2, so that the pinewood is on the top and on the bottom of the stack.
Liberally coat the wood pieces with Titebond wood glue using a paintbrush. Clamp the blank with plenty of C-clamps, as shown in Photo 3. It is a good idea to clean off any excess glue that oozes from between the wood pieces as they are clamped. Let the blank dry for a couple of days to ensure a good bond.
Shaping the Propeller
After the blank has had sufficient time to dry, select the outline of the propeller for your airplane. This can usually be found on the plans. Another source is from the many three-views that are available.
Make a cardboard template as shown in Photo 4 and proceed to cut out the propeller from the blank. If you’ve done it correctly, it should look like Photo #5.
Now the Fun Begins
It is a great help if you have a commercial propeller to compare to the carving, although it is not entirely necessary. I start by carefully cutting away large pieces on the front face and the rear portions of the propeller. If you cut too deep, you have just ruined the propeller blank. It’s better to cut not enough than too much.
Referring back to Photo 1, the rotary rasp in the drill motor can quickly take off a lot of stock. The rotary rasp and my large, homemade sanding stick that has #40-grit sandpaper glued to it are my main shaping tools. When shaping the propeller you must constantly check the different locations on the blades for the correct pitch and angles. The closer you get to a finished propeller, the finer the sandpaper’s grit must be to prevent the blades from becoming scored.
Shaping the blades is time-consuming and tedious. Keep sanding and shaping the propeller until you are happy with the way it looks. The propeller should look like the one shown in Photo 6. Now it is time to finish it.
Finishing the Propeller
Shown in Photo 7 are the items needed to complete the project. After a final sanding of the propeller with #400-grit sandpaper, spray it with Rust-Oleum Varathane Crystal Clear Fast-Drying Polyurethane semigloss spray. Two coats will usually be sufficient.
To make the simulated “copper” leading edge on the propeller, cut a cardboard template, as shown in Photo 7, and mark this outline on the propeller with a fine-point marker pen. Do both the front and rear of the blades. Use a small brush to paint this area with Testors gold paint.
After the paint has dried, make a tool as shown with a wood dowel handle and put a 1/16-inch piece of tubing in it to make a tool to simulate the soldered screw holes along the blades. Grind the tubing on the end to make it sharp so it can be used for making round indentations approximately every 1/2 inch. Use a toothpick to fill the holes with silver paint. See Photo 8.
The next step is to cut out an aluminum disk for the propeller hub. Lay out eight equally spaced holes for the propeller nuts. Next, drill the eight holes in the propeller with a #35 drill, roughly 1/4 inch deep. Cut eight pieces of 1/2-inch 6-32 threaded rod and install these in the propeller hub so they protrude.
Drill a small hole in 6-32 nuts so that when they are put on the studs, a safety wire can be run through them, as shown in Photo 8.
As a final touch, I like to put the Hamilton Standard logo decal on each blade. See Photos 10 and 11.
One more thing—each time you curve a propeller, it gets easier!
Keep ’em flying!
