Clean Sweep Submarines

WIP 8: Designing Propellers

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.

VICTOR III tandem propeller

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.

VICTOR III scewed propeller

Tandem propeller assembly:

Single 7 bladed:

Based on the info provided in the article of following dimensions were determined for both propellers:

VICTOR III blade cross-sections

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.

Tandem propeller:

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.

VICTOR III tandem propeller

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.

VICTOR III tandem propeller

Second layer of primer applied. Yeah, she is a beauty if I may say so myself.

VICTOR III tandem propeller VICTOR III tandem propeller VICTOR III tandem propeller

Presented on the stern

VICTOR III tandem propeller VICTOR III tandem propeller

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.

VICTOR III scewed propeller

Cleaning the faces of the hub

VICTOR III scewed propeller

The first layer of primer I sand of compleatly, I'm left with primer that filled up the saddles.

VICTOR III scewed propeller VICTOR III scewed propeller

And ready she is

VICTOR III scewed propeller VICTOR III scewed propeller VICTOR III scewed propeller

Thks & Grtz,
Bart

Practical wisdom is the school of experience [Samuel Smiles]