This Genius Propeller

Toroidal propellers are an innovative type of propeller that has a Taurus-shaped blade. The unique design of these blades resembles a donut, which is why they are often referred to as “donut-inspired blades”. However, these blades are much more impressive than they first appear. In fact, they have proven their ability to more than double the propeller efficiency when used on boats. This significantly increases speed and fuel economy. Additionally, these propellers can massively reduce the noise of both drones and boats, which is especially important as noise pollution can affect marine life and their ability to communicate and navigate.

The physical difference between a toroidal prop and a standard prop is obvious when you look at them. However, it is not immediately obvious why toroidal propellers have such huge benefits. By comparing the two types of propellers operating next to each other, it becomes a bit clearer. Firstly, there are far fewer bubbles, known as cavitation, coming off of the blade tips even though the blades are the same size and rotating at the same speed. This is because the toroidal prop generates less tip vortices which can cause noise, vibration, and reduce efficiency. This is believed to happen because the vortices that would develop at the tips are instead spread across the whole blade.

In addition, toroidal propellers bring in more surrounding fluid as they spin than standard props. As the die from further away is pulled into the blade, this gives a further increase in both efficiency and thrust. There are two main types of toroidal propellers: one from Sharrow, which has been focused on marine applications, and one from a research group at the Lincoln Laboratories within MIT, which has been focused on extremely quiet drones.

The benefits of faster, quieter, and more efficient ships cannot be overstated as they could decrease sailing time, reduce fuel consumption and emissions, and reduce noise pollution to marine life. This is especially important for large cargo ships, which are the backbone of global trade, traveling thousands of miles across the world's oceans to transport everything from electronics to food to raw materials. In terms of the boat's operation, it is said to increase handling from those that have tried it and it increases thrust in the reverse direction.

For drones, more efficient flight may enable new possibilities for air travel and reduce disturbances to people and animals nearby. The propeller gives incredible average fuel savings of around 20 percent, which is a significant benefit. However, the main drawback of the toroidal prop is that the complexity of the prop makes it more expensive to manufacture. Currently, they are made using CNC machines or by being 3D printed, which makes the Sharrow prop cost around five thousand dollars compared to five hundred dollars for a standard one. However, if the boat is cheaper to run due to its increased efficiency, it could earn this back over time. Furthermore, if toroidal propellers become more popular, the cost will come down due to economies of scale from mass manufacturing.

It is not yet fully clear how toroidal propellers will scale up to larger ships or aircraft as these generally use slower motor speeds. However, it is likely that some benefits could come from this. This is also just the tip of the iceberg, and there could be many more applications to come that we don't even know about yet, such as highly efficient hydro generators or quiet computer fans.

In conclusion, toroidal propellers are an innovative type of propeller with many benefits, including increased efficiency, reduced noise pollution, and decreased fuel consumption and emissions. While they are currently more expensive to manufacture than standard propellers, their potential cost savings and benefits make them a promising technology for the future of marine and air travel.