The Brennan Torpedo

[Snargfargle]

https://en.wikipedia.org/wiki/Brennan_torpedo

The Admiral wants me to add some personal comments so here is the formula for the fluid dynamics of a propeller. The YouTube engineer used a lever model explanation because fluid dynamics adds unnecessary complexity to the basic explanation.

F = ρ * A * (V_e - V_0)

• F is the thrust
• ρ is the fluid density
• A is the propeller disk area
• V_e is the exit velocity of the fluid behind the propeller
• V_0 is the free stream velocity of the fluid approaching the propeller

You will notice that the engineer printed several propellers before he found one that worked. This is because it's easier to just use pre-designed propellers than to create a unique one based on propeller theory when prototyping a design concept.

https://en.wikipedia.org/wiki/Propeller_theory

To add to this complexity, the actual torpedo had two contra-rotating propellers and two propulsion cords, which added the ability to steer the torpedo. This was cutting edge mathematical modeling for the day -- remember that this was a torpedo designed in 1877!

 

Edited December 29, 2024 by Snargfargle