This will be my second time I make a propeller, the first one was for my AKULA, there I used brass sheetmetal for the blades, now I wanted to add some body into it by designing the blades with actual airfoil shaped cross-sections.
David Merriman’s has written an excellent explanation of propeller making in a Subcommittee Report from some time ago, which I use as a reference.
I do not want to post a picture of the prop assembly without explaining what it takes to design a propeller. If you want the skip all this just scroll down, but in my opinion, this is part of the fun.
The specific VICTOR III I’m making here is equipped with a tandem propeller. The propeller assembly consist of 2 propellers, each has 4 blades, and turn in the same direction with the same revolutions, the aft propeller is rotated 45°, the complete propeller assembly has 8 blades.
Other submarines of the same class but with different hull numbers have the more known “high skewed 7 blade propeller”. I decided to make both.
Tandem propeller assembly:
Single 7 bladed:
Based on the info provided in the article of following dimensions were determined for both propellers:
Now that I had determined all this stuff, I could start making the propellers, fun isn’t it, I love it. Pictures below are the propellers at different stage’s of manufacturing.
All blade roots milled to fit the slot in the propeller hub(s). I numbered the blades to make sure they go into the right slot.
Blades were glued in the hub slots by means of thin CA, the root filled was accomplished by applying thick CA. I coated everything with a shot of primer, which was sanded down, touched up all remaining imperfections. The sanding paper is used to clean up the mating surfaces of the hubs. I also provided recesses and bosses for indexing the different parts of the tandem propeller.
Second layer of primer applied. Yeah, she is a beauty if I may say so myself.
Presented on the stern
Single 7 bladed propeller:
Bushings are a mechanic best friend. Made a 4mm bushing with an inner bore of 3mm that fits perfect in the bore of the hub.
Cleaning the faces of the hub
The first layer of primer I sand of compleatly, I'm left with primer that filled up the saddles.
And ready she is