SAW propeller for Hydro 2

[Ivan Kozyakov]

Hi guys!


I am preparing my Hydro-2 for the next season with 8s SAW setup (2000 Kv SSS, 240A Swordfish). In many SAW videos I have seen that they use three bladed propellers. What are the advantages of such a solution? How do they differ from standard semi-submersible ones?

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[Bande1]

they slip less

[NativePaul]

For a long time Octura's V series were the only props readily available with high pitch and lowish lift, and they are all 3 bladed.

[Bande1]

For a long time Octura's V series were the only props readily available with high pitch and lowish lift, and they are all 3 bladed.

as pitch increases, rake has to increase and/or blade area goes down. the prop has less bite on the water and thus 3 blades add blade area causing less slip. As rake increases lift decreases because the thrust cone becomes narrower.

this is what the prop dudes tell me, anyway.

[Ivan Kozyakov]

Does this make sense for all three blade propellers? Or only for special ones SAW with low lift? Can I buy an inexpensive 1.8 pitch prop from Aliexpress for the first tests?

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[Bande1]

you got to be careful because 2000kv is extremely high for 8s and youre very likely to destroy something. You really need to lower the RPM and raise the prop sizes. or get a TP competition motor rated for those RPM's. 1000-1400kv is much more appropriate outside the very specific high RPM motors that have extra kevlar around the magnets to turn that fast.

once you get that under control you need to use the prop calculator to find out where you need to be. you have to start off slower and monitor temps. thats absolutely critical to start slow.

[LibertyMKiii]

I am interested in trying 3 blades as well.
My logical conclusion is that having a blade in the water 33% more often per RPM will net a much higher load on the motor. It would be wise to start with a 2 blade and see where things are with temperatures and then move to a 3 blade.

Having a higher amperage draw will result in lower RPMs and in some cases this is why more blades = less top speed. The setup has to be optimized for 3 blades.

[Ivan Kozyakov]

you got to be careful because 2000kv is extremely high for 8s and youre very likely to destroy something. You really need to lower the RPM and raise the prop sizes. or get a TP competition motor rated for those RPM's. 1000-1400kv is much more appropriate outside the very specific high RPM motors that have extra kevlar around the magnets to turn that fast.

once you get that under control you need to use the prop calculator to find out where you need to be. you have to start off slower and monitor temps. thats absolutely critical to start slow.

Yes, I understand the risk, but I want to do this for the sake of experimentation before buying a new motor. Moreover, according to the calculator load RMP will be 49K, the maximum for this motor is 50K by manual. My current setup is 6s+46mm/1.8 pitch prop and the motor is a little warm.

[Speed2]

The abc 1820 22 45 2 blade. For saw runs you may get away with the 2000kv on 8s. You just have to make sure you have proper cooling. Also the 240amp swordfish is like not going to be good for a setup like this. The castle creation hydra is likely going to be the best esc for your goal. The hydra is an 8s capable esc that will handle well over 300amps for a saw setup.

[Veloctiykingsracing]

2000kv is absolutely fine for 8s SAW runs. As mentioned, go w a hydra, check your data. The Swordfish is much less forgiving. If the data suggests your amp load is within range for using the Swordfish, then use it.

[Bande1]

2000kv is absolutely fine for 8s SAW runs. As mentioned, go w a hydra, check your data. The Swordfish is much less forgiving. If the data suggests your amp load is within range for using the Swordfish, then use it.

you dont even know what size it is. the biggest SSS 2000kv is a 4092 rated for 23v max and 4200w peak, which is only 150A on 8s.

https://tflnorthamerica.com/wp-content/uploads/2020/07/TFL-SSS-Motor-Specification-List-2020-2.pdf

[Ivan Kozyakov]

you dont even know what size it is. the biggest SSS 2000kv is a 4092 rated for 23v max and 4200w peak, which is only 150A on 8s.

https://tflnorthamerica.com/wp-conte...ist-2020-2.pdf

4082 2000kv, 31v Max. And even 60K RMP Max

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[Veloctiykingsracing]

you dont even know what size it is. the biggest SSS 2000kv is a 4092 rated for 23v max and 4200w peak, which is only 150A on 8s.

https://tflnorthamerica.com/wp-conte...ist-2020-2.pdf

Again, it would be fine for an 8s SAW run. Do I have to buy one and prove it?

[Bande1]

you see that 3200w rating? 3200w / 28v = 114A

[Bande1]

Again, it would be fine for an 8s SAW run. Do I have to buy one and prove it?

yeah and do it with an 1820. be fun.