[superlefax] real-world propeller comparison

[superlefax]

Hello folks,

my setup is now working for over one year now without any major problems. So that’s why I had plenty of time to test different propellers. Thanks to all of you guys modeling those props for us!!

The test setup is made of the following components:

SSS 56104 700kv / Neugart PLE40 8:1 / ESC FLIER 16S 320A / Takuma SUP Clone / custom made board / aluminium pod with axial sealings / 20Ah @12S Lipo

The most important values to compare the various propellers are:

-foiling speed [km/h]
-battery current [A]
-battery voltage [V]

The voltage of my 12S is between 44V-46V while foiling.

I can see the present current on my electronic box while riding. Simultaneously I use the app “Windsport Tracker” for Android which tells me the speed via voice on my mobile I have with me. So I just need to focus to ride 20, 25, 30 km/h and write down the Ampere.

Conclusion: The Hiorth propeller is my favourit for a 3D printed prop. The Flying Rodeo prop is now the one I’m using at the moment.

Cheers,

-superlefax

[Alexandre]

well done! thank you, by any chance you know your actual top speed with the FL propeller?

[Jezza]

It would be interesting to see if there is any difference in using PLA for the tunnelvision prop and cutting the rear flange off it. I’m pretty sure that flange adds to the drag.

[superlefax]

Not yet. I bought it just one week ago. I think I need to find it out in the name of science

[erwan]

thank you! it’s really interesting!
So the FR is a good propeller, even with a 1/8 gear ratio.
What do you mean for the 180mm, “could not handle the acceleration” with 180 it’s too much power?

the duct make a huge difference in consumption, raise 10 amp more in general.

[superlefax]

Well at lower revs (less throttle on your remote) it has more torque compared to prop with smaller diameter. That means that it was tough to handle the small throttle range on my old winning remote with this torque monster. But this can be solved by limiting the ESC to max. possible throttle position to e.g. 70-80%.

[Alexandre]

Diameter and area of the blade , my understanding :it gives more thrust for less motor torque so less amp but the full voltage : rpm cannot be apply ( see my post rpm drop …) at some point (rpm)trust needs rease too much torque and so amp (more power more amp less voltage …).
The Hiorth propeller can pull 2 boards i saw , so i think we can decrease a lot blade area, if we aim for 30km/h top speed , diameter around 135-140 pitch around 220-240mm and “smaller blades”
For the FL propeller i needed around 3000 rpm for 30km/h with a big wing takuma v100 on my setup , may be less drag and less amp be acheived with the RL board wing …

[superlefax]

How much amps are you drawing at the specific speeds?

[Alexandre]

I was around 115A on 8s with a 40mm 860kv and 6:1 , not the best setup for 30 and 80A for 25km/h

[waterfox]

Great comparison!
If you ever feel like testing one more: I designed my prop for the same motor and the same gearbox combination at 6S.

https://github.com/Waterfox/E_foil/blob/master/Propeller6_2_14kn4B.STL

[superlefax]

Hi Waterfox, Can you provide the STP file?

[waterfox]

Hey,
I’ll save and upload as soon as I’m back at my workstation on Monday. I think you should be able to pull the file out of my STEP thruster assembly here:

Waterfox/E_foil

R001-GEO_1 - Kitefoil Thruster Assy.STEP

[Alexandre]

I missed that , You have the 4 blades FL propeller , i use the 3 blades … Good trust to pull out and fly , the funy thing is when i stay ON the water ,full thorttle top speed is “low” ( no measured) but when i get on the wing , speed increases a lot … You can fly “fast” and with weight on the 3 blades propeller
I don’t known if the 4 blades has the same pitch… But the 3 blades is way enough for 30km/h which seems to be a good ratio fun/amp ( Time)

[tylerclark]

This post would be exponentially more helpful if it had links to the different 3d prints.

[superlefax]

Got it. Your design looks really impressive! Is your pod working?

[waterfox]

Thanks! Yeah it has been working reliably for about a year. There are some vids on the github site.

That prop is an H105 profile that should be at 3 to 4 degrees angle of attack at its design speed of 14 knots. This summer I was going to try going to 3 blades because i currently have more than enough torque / propulsion force.

[XSailor]

Nice forum, loads of information shared. I am only in planning stage but anyway collecting information. Just for comparison, found on Youtube a foiling tohatsu 5hp and here some data for that. Probably not ducted but anyway. The boat max speed 32 km/h with a 5hp= 3.73 KW. Pitch was 9. Max rpm for the engine is 5500 and gear 2.15/1 so prop speed is 2558 rpm. Considering theoretical speed(no slip) should be about 35 km/h the slip is very small, only about 8 %. So the standard outboard propeller should work fine in this speed and power range? Boat is heavier than a foiling board but also foil type is totally different so for sure not comparable. The result is still kind of surprising as understood from reading here that outboard propellers does not work “as is” so good on foils. Wonder what kind of torgue a 5hp 4 stroke outboard can produce, maybe more than the engines used here? Would be nice also to know how much a duct would reduce the tpend speed on the Tohatsu. Here a link to the video: https://www.youtube.com/watch?v=89ExF3xb-6g&t=3s

[superlefax]

I now have a comparison for the SUP Takuma Clone VS. RL-Foil

VS.

RESULTS

I’m really satisfied with the build quality and the overall consumption is about 20% less. That means 20% more ride time!
Max speed is 34 km/h. I really can recommend it!

Cheers

[Alexandre]

@superlefax: Did you use the “takuma” mast for RL wing ?

[superlefax]

Yes. I needed to bore a third hole in the RL fuselage to mount it properly.