Motorized Watercraft on a Hyperdimensional Planet

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Discussion Overview

The discussion revolves around the mechanics of motorized watercraft operating in a hypothetical 4D environment. Participants explore the implications of propeller design and orientation in four dimensions, considering both theoretical and practical aspects of propulsion in this context.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant suggests that in 4D, a propeller could rotate in the ana-right plane, allowing for operation in shallower water.
  • Another participant expresses that the axis of rotation for a 3D propeller must align with the desired direction of movement, questioning the effectiveness of a propeller oriented along the 4th dimension.
  • A different viewpoint indicates that in 4D, a freely rotating body does not have a unique axis of rotation, complicating the concept of thrust direction.
  • Concerns are raised about the stability of thrust direction in 4D, with a suggestion that ducted propellers might be necessary.
  • One participant proposes that propeller blades can be shaped to direct thrust in specific directions within the forward-up plane.
  • Several participants inquire about the dimensionality of the ship and propeller, confirming that they are considered to be 4D objects.
  • References for further reading on the topic are shared among participants.

Areas of Agreement / Disagreement

Participants generally agree that the discussion pertains to 4D mechanics, but there are competing views on the specifics of propeller orientation and functionality in this context. The discussion remains unresolved regarding the optimal design and operational principles of propellers in 4D.

Contextual Notes

Participants express uncertainty about the implications of propeller design in 4D, particularly regarding the stability and effectiveness of thrust direction. The discussion highlights the complexity of defining propeller mechanics in a higher-dimensional space.

Who May Find This Useful

This discussion may be of interest to those exploring theoretical physics, higher-dimensional mechanics, and the design of propulsion systems in unconventional environments.

Hornbein
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Consider a ship with a propeller. A propeller has to be perpendicular to the way you want the ship to move. It has to be perpendicular to the forward direction. In 3D that means that the propeller rotates in the right-up plane.

In 4D we have other choices. The ana-right plane is also perpendicular to the forward direction. The propeller could rotate in that plane. That means a horizontal propeller. Such a ship would be able to operate in shallower water, so it seems like the clear choice.

(In 4D the dimensions are up, forward, right, and ana. Only up is vertical, all others are horizontal. So the right-ana plane is horizontal.)
 
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My limited understanding: For a 3D ship, the axis of rotation of the propeller has to point in the direction you want to go. If you simply rotate the propeller so the axis of rotation is along the 4th dimension then you'll just apply a torque to the ship and rotate it, just like rotating the propeller so it points to the right instead of forward.
 
In 4D the "axis of rotation" concept applies only in special cases. A freely rotating body has no axis of rotation, instead it has two planes of rotation. In the case of a drive shaft for a propeller you fashion and constrain it so that it has only one possible plane of rotation. But then it doesn't have a unique axis. There is a whole plane of directions in which you have prevented it from rotating.

4D propellers confused me for a long time. The thrust has to go in a direction perpendicular to the plane of rotation, but there are a full 360 degrees of perpendicular directions. Which one? Is it stable? I thought it would be necessary to use ducted propellers. Then someone came along and pointed out it was possible to shape the blades of the propeller to push the water in one particular direction. Oh.

In this case, the propeller can be shaped so that the thrust goes any direction or directions in the forward-up plane. Forward only is the direction you want.
 
Is the ship and propeller 3D or 4D?
 
Drakkith said:
Is the ship and propeller 3D or 4D?
We are in the 4D Universe so every object is 4D.
 
Last edited:
Hornbein said:
We are in the 4D Universe so every object is 4D.
Ah, my mistake. Got any good references for this topic?
 

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