Recent content by Victor R

Thanks to discussions on the forum, ideas emerged on how to simplify the drive, reduce its size, and at the same time improve its maneuverability. First, I need to get rid of the fin rotation mechanism and replace it with a stepper motor, as @Horton HCCI suggested. But the stepper motor should...

I'd like a drive that achieves the same goal, but it won't be as elegant as the Voith Schneider Propeller. Voith Schneider can instantly change thrust from one direction to any other. With the Cardan Gear, the thrust direction will change sequentially, like an Azipod—to move, for example, from...

I have no doubt that everything could be done completely differently, for example, using linear electric motors. But that would be a completely different story :rolleyes:. LinX Linear Motor Demonstration:

Yes, you understood and drew everything correctly. It is possible to combine a leading heave Tusi couple mechanism and a slave pitch Cardan gear mechanism. I wouldn't want to place a servo motor on a moving part, increasing inertia. Furthermore, the servo motor might not provide the required...

This was a test of attentiveness ;). The leading edges of all blades in a Voith Schneider Propeller always point in the direction of rotor rotation. In a trochoidal propulsor, the leading edge of each blade points against the flow, as in flapping foil propulsion. Cycloidal Rotor in Motion |...

Yes, of course they were, here's one of the articles: The effect of chordwise flexibility on the thrust and efficiency of a flapping foil. The article provides the following conclusions: Chordwise flexibility in flapping foils, if properly selected, is shown experimentally to improve efficiency...

I currently have one model. It uses a fin with a hard, replaceable shell with a NASA-0018 profile, 3D printed from ABS plastic. The fin measures 400x120x22 mm, an area comparable to a rowing oar blade.

A tricky question that can cool creative ardor o_O. One can only assume that in a design with a reciprocating fin motion, less energy is wasted on unproductive water swirling than in a design with a circular fin motion or a rotating propeller. On the other hand, it's clear that the...

I think a better comparison would be the ABB Dynafin trochoidal propulsor, which has several fins, each driven by an individual electric motor, but all moving in sync: https://irso.info/wp-content/uploads/2-11-Viherialehto-S-ABB_DynafinTM.pdf

Yes, a balanced drive requires two fins operating synchronously in antiphase. This significantly complicates the drive mechanics. But with an electric drive, it's simpler to use two separate single-fin drives and synchronize their operation not mechanically, but through an electronic control...

I drew a diagram explaining the change in thrust direction from 0 to 180 degrees towards one side; towards the other, the picture should be mirrored. How the plane of fin oscillation rotates at the same angle as the central gear of the Cardan mechanism is rotated, I think it will be clearer...

You're absolutely right! One such detail is the need to adjust the optimal fin angle of attack on the fly depending on the boat's speed. To achieve this, it is not enough to simply regulate the speed of the electric motor. You also need to adjust the fin's angle to the flow direction while it...

Hi Horton HCCI, thanks for your question. I have nothing against guides, but they are not used in this mechanism for an important reason. In the mechanism, as I already mentioned, the direction of thrust is changed by rotating "that invisible rectangle that traces the fin's movement" at a...

To change the direction of a propeller's thrust, it must be placed in a rotating chassis to create an azipod. A fin propulsor has the ability to change thrust direction built right into its functionality. To change the direction of thrust within small limits for steering, it is sufficient to...

There are many theoretical studies; here's one review: Flapping Foil-Based Propulsion and Power Generation: A Comprehensive Review Practical implementations are fewer, such as the O-foil: O-foil promotion I'm not looking to outperform the propeller, I'm just trying to test the drive idea...