Propulsion System - Motors, Gears, etc


#508

Yeah, that is guaranteed to break! For general consumers you want to make a product super simple and robust!


#509

I think one person has ordered it, but there are no test results at this stage.


#510

OK thanks
jezza why do you think it’s gonna break?


#511

I was talking about the jet system with the automatic cover.

The motor from Reacher tech, I think that might work well if the specs are correct.


#512

Looks like this board uses a similar engine to Reacher Tech’s? Look at the shaft.


#513

So you’ve noticed something familiar here : :thinking:

Reacher-Tech%20quest


#514

Iam not sure :sweat_smile:Screenshot_20190508_220958


#515

Fliteboard were using a geared setup. Whether they’ve changed that or not I don’t know. They had the setup on their website.


#516

Your right I saw the picture looks like they use gears


#517

Hello Boys i need to know if i need a reduction on this boy :


#518

It would probably cope without…
Basically you need a direct drive in the 70130 region with 130kv. Capable of 60v and 5kw.
Lift use a motor in the 130kv region (I have measured)


#519

130kv at 60v means 7800rpm this would be in the water around 7000rpm is this not to much¿


#520

I don’t think it’s too much. Under load you won’t hit that RPM and once it’s on the foil it will behave quite differently to a prop on a boat as there’s way less resistance. I am going to hook the motor up to another ES at some stage to pull more data off it with a data logger.


#521

@Onhill.
The motor will have the 7800 rpm under load theres no rpm drop. if you loose that much rpm your esc would be grilled in 2 seconds :wink:


#522

No it won’t! Try running a brushless motor cutting aluminium on a milling machine and you will see just how much RPM drop you can have without blowing an ESC.
7800 RPM would assume 100% efficiency which is definitely not the case. There will be voltage sag, heat losses, inefficiencies from the prop.
If you don’t believe me simple try a drone motor with and without the prop.
Often with load a motor will be running between 50-75% efficiency


#523

I’m pretty sure that this one is the magic inrunner we are looking for. I asked them some questions and it turned out that they already sell this motor to commercial Efoil companys (That’s what he said).


#524

So the only question would be what kv we need :slight_smile:


#525

Yes but on a cnc you will have an ecu that’s measuring the back emf an. That means it can handle an rpm drop und just cheng es the motor speed. The escs we are using won’t do that. So they will give out a field that is not chaning depending on the self inducted field of the motor.
Pls someone correct me if I’m wrong :slight_smile:


#526

On my CNC I’m running a 500kv RC motor with a 60A yep ESC. It runs better than the old motor that came with the CNC.


#527

You are wrong, all common RC ESCs will measure the rotation and commute accordingly. Vesc and other ESCs meant for the use of BLDC in electric vehicles like bicycles and cars will additionally limit the phase current.