I feel I need to mod the shaft of the 100kv so that it can take the FR prop and a spline prop. That way I can test a full range of props on it. The FR prop will come out tops bet, but it’s still fun to try see if something else comes close.
The only motor I know has fried has been the guys that built a foil boat. Not sure how much current they pushed through it, but I know it was running at 10s which is not enough for this motor.
It is never the voltage that destroys a motor, it is the current.
Whether 6, 10 or 14s does not matter.
greetings Frank
Hey Jezza, I have been testing this prop on the grunty geared setup, I spun the rubber hub at 40% throttle during first pool test…
Spun it loose? …
almost loose, the only thing that prevented it flying off the shat was the stainless washer on the nut
Yes there is one efoil fried motor. Mentioned in my build
Btw I had some good ride with the 120kv today. Will share the logs compared to 100kv also there if anybody is interested
I dont think any of these motors are getting to their theoretical max rpms.
My 80kv reacher tech with FR prop gets me to 38kph on my 1650 wing. I cant keep the wing down after 38kph, so I know there is more speed to be had, even with the 80kv. I cant see the advantage of the 100kv or 120kv motors. I think the extra turn of copper on the 80kv is needed for me. 95kg.
What speeds are people getting from there 100 and 120kv motors?
I’m going for a speed run on my Old naish WS1 tomorrow, so I’ll post my results.
Wow, that is probably true. It seems the FR prop really is the one to beat so far.
What amps and voltage are you at when you are at 38kph?
Is that the Naish Jet wing?
I am trying to learn from you guys so I can get mine together and start riding under electric power.
What battery are you using?
With my 100kv and 120kv motor with FR six inch prop I always reach max rpm. First one is around 31 and latter one 37km/h max speed. I need to check my logs but this is roughly how it is. 12s battery. Which FR prop version do you have? Must be higher pitch if you run 12s
Im running a 14s14p battery. 6 inch FR prop. My cruising amps are about 35-40 from my calculations but not 100% sure. My cruising rpm is 2600rpm at 30kph. Im not 100% sure on my amps and rpm at 38kph. Too busy trying to keep the Naish jet 1650 in the water, to look at the remote. Throttle feels at about 80-85%.
@Ackermann Do you mean max throttle? What Prop rpm are you getting?
That’s not possible. That would mean you have a negative prop slip.
Even with a super efficient setup and a very low prop slip of 7% you should use 3500rpm to get to 30kph.
Do you not mean 3600rpm which would give you a prop slip of 8.3%?
I’ve hit 38kph on the 120kv with 12s and FR prop a few times. It seems to pretty much be close to the max speed I can get it with super fast and efficient foils.
I need to build my pack up to 14s at some stage and also modify the shaft of the 100kv to take the FR prop.
Agree, 120kv 12s 38km/h FR 6"
You will not have fun with 100kv on this. I have like 10logs on this setup. It’s max maybe 31.
Just going off the Maytech remote which I set on cruise control. and my average speed being 30 kph.
Defiantly not 3600 rpm, but yeah the numbers dont add up do they.
Ill get some better numbers tomorrow when Im out.
So from your logs you are getting 40 kph from 4000rpm at the prop with 45V. Would full rpm for a 120kv not be 5400? minus whatever loses come into play. Seems a bit far away from 4000rpm. How do you calculate getting full rpm. I might be missing something here.
The 40km/h is downstream, you should refer to the speed on the Donau Side arm which is more stable (starting at 17:46). Theoretically I should have around 5000rpm for 45V (0.95 duty) but instead I have 4300. Seems okay for me? I try to log max duty in air today to get a reference
In my 100kv speedruns there is a similar rpm behavior
To hit 30kph with the FR prop, the minimum rpm needed with absolutely no slip is 3300rpm. There’s no way you running with zero prop slip though, so mathematically you are most likely running between 3600-3900rpm to hit 30kph depending on which foil you are using.
We’ll never see full RPM under load with these motors as they just don’t have the toque to get there.
My 80kv gives me about 4400 with no load so maybe the extra copper wind will get me closer.
Looking at @Ackermann logs, the motor seems to saturate at about 125 motor amps at 95% duty. Where you saying the 100Kv acts the same way?
Anyway, will be interesting tomorrow when I pay attention to the numbers on the remote.