Well, means the diff is too small to motivate price. It’s not like it’s hard to do a simple test, hard to get all conditions comparable, yes, but if you want to show a 600$ difference then i think the improvement should be clear even in a simple test with some measurement spread.
Let’s say EfoilSolution is the first company daring to sell a toroidal version. The first one means “monopoly situation” with "monopoly prices (It’s no coincidence that prices have risen by a factor of 2.3 since June). When (if ?) the competition kicks in, prices will necessarily plumet unless IP rights are applied…
Toroidal props are not more complicated to cast than 3 blade ones.
Let’s imagine next November we have three competitors with a mean price of 180usd, what would you do ?
I would not stick a finger in it, or a toe (more likely to happen by accident)
Would you?
I would probably not buy it. I am not convinced that it is safer (finger getting into loops) and i doubt it will be more efficient, the smell of hype is too strong still.
We’ll know in a year, maybe.
Many (50% ?) riders decide to remove the shroud on fixed or rotating blades. Highly dangerous but take the chance though.
It’s only the perpendicular direction to axis of rotation which is safe with toroidals. The finger is ejected without cut.
You are right, it is not enough but still safer than standard propellers without shroud.
Corrected… 
EDIT: see the e-Surfer test just below, no prop guard with the standard prop and none with the toroidal either.
A first test of the EfoilSolution toro prop by E-surfer Germany (August 6th 2023)
Very sleek, probably CNC’ed in a single alu block. The long machine time explains the price.
As a first subjective impression, no data, “rides soft and easy” “too early to give a final impression” “rides much faster on remote with level 6 position than the standard LIFT prop”.
A final impression was supposed to be released a week after (circa August 15th)
Still in progress…
It will be interesting. The lift props are 6" pitch so if this is 7" it would feel faster at the same trigger position. They haven’t actually released what the pitch is so no one knows.
Rich “Lifters” probably won’t care and just purchase it anyway…
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So the company that’s selling the prop for $589 has supplied a prop to be tested and compared to known props AFTER they started selling.
The prop is NOT made of the same material as the one they are selling and MAY not even be the same shape exactly.
How is that a fair comparison test and what value does it have to any potential customer.
What’s the saying that P.T. Barnum is credited with……
There appears to be some discontinuity between the surface blends on the prop. I attached an image highlighting the apparent line. I wonder if it’s noticeable to the touch?
Seems crazy if this an artefact left over from the 3d modelling. Maybe where the prop is turned over or repositioned during milling?
They might end up painting it to hide any artefacts. I noticed some nicks and possible scratches. Would be nice if they posted a behind the scenes video of the manufacturing process.
It’s already been said but one (Sharrow, MIT) can patent a product whose benefits are barely convincing but has potential, let the tinkerers finish the development and then appropriate the advances by saying “we told you so”. Among the communities capable of guiding the development are efoilers and drone fans. The former feel the progress in their bodies through their legs, the latter through their hearing and their joysticks.
Here are the April 2023 advances made by the drone community: the donut shape - strong, cheap but a bit small.
Cutting both extremities of the donut is promising as it reduces the round tips whose net gain isn’t finally proven. It transforms a dual loop propeller into a four bladed one…
I might help with the behind the scenes process : They come here, take some design diyers have been working on, slightly tweak them and sell them.
Simple recipe.
Here is my prop for a flipsky 65161 motor, still working on epoxy coating and sanding mine for testing.
This design is around 58% efficiency cruising at 1500 watts, 16 MPH
Looks like a 2 blade version would be around 63%, I left it 3 blade because my board is very difficult to get up on plane and the loss in low speed trust may make it impossible on my setup.
Top speed I am shooting for higher than 25 MPH
https://www.printables.com/model/576544-toroidal-prop-for-efoil
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How do you measure the efficiency?
CFD, output power (linear speed and thrust) / input power (RPM and torque)
You done any correlation of the cfd model?
i’d wait until ridden before stating any efficiency figures.
I confirmed my CFD model using my old wageningen b series 3d printed prop model and this dataset https://deepblue.lib.umich.edu/bitstream/handle/2027.42/91702/Publication_No_237.pdf?sequence=1
Efficiency numbers from riding are a combination of motor efficiency and propeller efficiency, a test stand would be need to actually get propeller efficiency. Hence why people report kw/km here because it is combined efficiency not propeller.
All I am doing here is making the prop that I want for own setup, if it happens to help anybody else I am happy to share. But I am not here to argue with random people online about if my CFD numbers are 100% accurate. I am sure they are not. I am also sure it is not a perfectly optimized design. If I could do that I would own a prop design business.
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Sorry, and exactly. It’s just that 58% and 63% are very exact figures, i’d think both within the uncertainty of your calculation.
I just realized I forgot the tail cone for people that already downloaded the model. It is uploaded now.