How rack and ratio ? Maybe cavitation and pla doesn’t work well …
my rake : 15
pitch: 180mm
diameter : 150mm
expanded area ratio : 0.65
after discussion with bruno from alien power, maybe lost of sync ?
expanded area ratio is too high ? ==> too much torque ?
Today I gave a shoot to the 142-216, printed in PC Max and reinforced with a thin fiberglass up to 1/3rd of blade span.
The SSS350 sound smooth at 12s, unfortunately my amp/voltmeter died this morning but more than 7 nautical miles at a MINIMUM speed of 16Kt and the batteries are at 3.8V per cell. I realized that below 17/18kt I foil unconfortably, my setup start to feel safe from 18 and above, cruising at 20-21kt is less demanding.
Unfortunately, the prop max out at 23Kt… less than I expected. Next trial will be 140-230 but I know that it won’t make me happy…too little blade surface to be effective.
I really want to dig into 2blade design…
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Just to be sure, you are running the SSS56114 360kv at 12S with a 4:1 reduction ratio, which gives you around 4000 rpm unloaded, right ?
Yes, that one. Actually is marked 350KV, I had the 360 before and this one has a slightly longer magnets on the rotor… Got it from Germany. Battery: 4x Multistar 16A 6s, serial parallel up to 32A 12s
new prop…
26kt reference on the right, the 140-230 on the left (requires some sanding). Too little blades, maybe ok for flat water low motor current request… I’ll try next time.
26kt reference on the right, the 140-230 on the left (requires some sanding). Too little blades, maybe ok for flat water low motor current request… I’ll try next time.
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Nice prop! How does the twin blade feel like?any vibration or tendency to “steer” to one side when foiling?
I played a lot with Caeses B prop generator but I never got what really I wanted to design…
Twin and 4blades are both something worth to play with.
Only the 2blade scares me (on second thought) because of typical shaft vibration hence sealing at risk.
I have no issues with this Prop. No Vibration. Runs very smooth and quite.
I guess, the FR prop is made with this tool. I played around a bit and i got one close to the original.
But dont know the exact Diameter/Pitch of the FR
I finalized a couple of prop on Caeses, 3 and 4 blades, the pitch as diameter ratio look like not real, comparing with the Javaprop ones but the blades are really nice.
Will try to print a 4 blade and let’s try.
I agree with the ratio stuff. I wish they just used the standard pitch concept of inches instead. It would make much more sense.
Ok guys, I played a bit with Caeses online prop generator and made the following :
135 mm diameter
6,67" Pitch (you don’t choose this parameter on the generator but you can calculate it with p/d ratio)
Prop is made for top speed of 35 knots (65 kmh) @ 6600 RPM (130kv motor at 14S).
Still not tested
Stl and Inventor files are available. I just don’t know how to upload them.
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thats not the same.
KV is no load. So full load 66RPM is more like 200KV (theoretically if you optimizie for max power it will be 260KV)
You are right, my mistake. I mean 6600 RPM under load, so kV depends on slip + voltage.
The pitch is way to high if you want to run it at 6000RPM, and I would suggest you design one for 4000RPM
As far as I know, prop design is really difficult, even with a good software. I guess we won’t know until I test it.
In the meantime, I made another one based on @MaB prop. This one is designed for 35knots @ 3730 RPM. I logged all values entered in the generator to be sure to be able to tweak them if needed. Prop is 140mm dia and 262mm pitch and looks really close to the high pitch one you can find on the first post. Also, front cap is reworked to avoid cavitation.
Will test it hopefully in the coming weeks.
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I played a little with Caeses… don’t ask me which pitch is that but it’s nice! PC-Max, epoxy fiberglassed, will try it and if worth share the file. If not…add it to the pile of junk props due to recycle.
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Nope. To be scrapped.
2blades have been abandoned (mostly) in marine applications for some reason. Performance is not even close to 3 blades, manoeuvrability also, annoying vibration which seems to set back the motor, it struggled to get up to full speed but at partial throttle also was not pushing hard, like with excessive pitch prop.
Unfortunately I’m running suicidal since one month, no switch no volt/ammeter no fuse… So I can only judge by the fact that I found many solder joint melted, almost lose! One motor cable with xt150, the parallel connector awg10 inside the battery box, almost gone.
At the end of the day, I can tell that Caeses app is cool and produces better profiled blades, but more fragile 3d printed so fiberglassing mandatory.
3 blades is the good tradeoff, I will try to crimp the most of the joints fron now on.
Back to prop, the 3 blade today took me to 24kt, and it’s gentle on the motor/esc
Would you try the design I posted above if I send you the 3D files ? I won’t be able to test it before I got my motor pod ready, hopefully next month.
I’m taking a break now because I need to redo some wiring and rework the board, but send me a .step or igs and I’ll see when ready again.