For who try/have tried direct drive with outrunner


#384

You are right about the gearbox consuming a bit of the power. The Neugart PLE40 5:1 runs about 97% efficiency from memory. I dont think you understand how a 5:1 gearbox multiplies torque. It takes the 25000 RPM at 2Nm from the motor and turns it into 5000 RPM at 10Nm, minus your 3% power loss. Obviously there are other things going on to effect RPM and torque to the prop, but in a nutshell, that is what the gearbox is doing.


#385

As michion said, a gearbox basically lets you trade RPM for torque and vice versa. A 2:1 gearbox should give you twice the torque with half speed, a 1:2 gearbox doubles the speed and halves the torque. Thats the reason you can go really fast in 7th gear in a car but struggle to accelerate. First gear is the other way around. Lower gears in a car are reducers, higher gears multiply the motor RPM.


#386

Hi WNT,
Any update on your high efficiency propeller ?

Many thanks,
Al


#387

If you can spend the amps, the geared motor seems to be more powerful, but tell me, why do you cool gearings?
With direct drive concept, the motor bearings are used directly, in the way they were designed. The force comes from the magnets inside the rotor. They translate directly into the propeller thrust. I should have patented some aspects of this, instead i gave it to everyone. :wink:
If i count it right, the direct drive has 3 deep groove ball bearings, how many has the geared one? And how many seals? I would suggest one for the direct drive as well. Although the sealed ball bearings are holding strong with standard grease. And a thight 3D printed cap for the circlip bearing.


#388

Hi WNT did you ever manage to get this done? thanks


#389

Yes, I can pull 3500W for a maximum of 1 minute. After that, the Vesc starts limiting the current.

Regarding plastic props, they are pretty stiff. It bends a bit but doesn’t break. Same for 3D printed PLA props.
I don’t know if using an aluminium one makes a huge difference though.

I have read here that you managed to go up to 16km/h using 2200W battery. Any Idea on how much Amps were pulled by the motor at that speed ?
Eventhough I managed to pull 3500W, it seems that your setup is way more effective than mine ! At 3500W, I’m only cruising at 10kph for now !


#390

Not only will you find slippage in the prop due to bending, but you will also lose power due to oscillation in the bending. In a long-term application, aluminum is the way to go.


#391

@Flo, i am PowerGlider being on vacation and i cannot use my usual account , can you please send me a private message, i need some support regarding your fantastic program espap you gave me some time ago. I got huge amount of data now, but struggle to analyse it.
Thanks a lot!


#392

I read through a couple of threads now and I’m still wondering if anyone has ever successfully “foiled” with the 6384N @PowerGlider motor ? Power Glider, you’ve only used it to propel your surfboard, but not actually on a foil or am i mistaken?
I’m about to order a pair of 6384N Motors, but just want to make sure it’s actually possible to foil with these. Otherwise I’d order a spare 80100 just so I have a motor that I can foil with for sure.
Also, if anyone has ever foiled with that motor, did you change any bearings ? Or how long do the stock ones last (approx.)?
I was planing to do a 6384N Powerglider - ARC200 direct drive setup, Prop: Not sure yet
I’d be thankful for any info


#393

Hi, foiled with both, the 63 may not suit if you weight more than 75kg

For the 80 the bearing got rusted instantly, needed replacement


#394

My stock bearings lasted about 15 hours of use in saltwater and were still going with no signs of corrosion/rust. I soaked the entire motor in corrosion x every 3 to 4 runs. I swapped them out to try sealed bearings which I am currently using.


#395

Did you use any other waterproofing technique or did you simply soaked the motor in corrosionX?


#396

I would just soak the entire motor in corrosionx for about 10 minutes and then pull it out and let it drip dry and reuse the corrosion X


#397

I cannot guarantee that you can you foil with this motor, although i think that 30kg stand still thrust at around 2.5kW are enough for a lot of fun.
You should use a stainless steel 10mm rod. This implies you demount the existing one. I use a simple gas torch to heat the aluminium part while i cool the magnets with wet cloth from the inside. You need a lot of power to make it heat up quickly, so the bell does not get so hot. First unscrew the set screw and than you can use a parallel vice with protective jaws to support the bell and drive out the rod with a hammer and an M8 screw e.g. . It works best while it is still hot, but do not be afraid, normally it is not so tough.
Round and polish the end shaft of the stainless rod.
You need a lathe to cut a groove for the circlip. I cut this around 2 mm distance from the end only. Be careful not to hammer on this side after cutting, because it will deform the groove for the circlip so it cannot be held safely anymore. I lost a motor with prop by this way. Use a parallel vice to mount the rod in the aluminium part. Use a set screw to secure it. If you want to be able to unmount the rod later, please do not forget to make a flat area on the rod where the set screw can dig in. Otherwise you damage the surface of the rod making it impossible to unmount it without damage to the fitting.

By the way, there is a new motor in stock, i already bought it, the 63100 140Kv. Actually it has 132Kv. It has even higher power and with higher current also more torque. I did not test it yet despite the no load RPM. There are also some drawbacks: It has no holes which can be used as water outlets, and no threaded holes to mount a prop so it has to be machined first. I am in loose contact with the manufacturer.

Bearings: I use Stainless Steel bearings ZZ. 3 pieces you need.
I use universal grease to fill the tunnel between the bearings by one third or so.
Now comes the trick: You need a cap to protect the circlip side from water ingress. You can 3DP it. Glue it to the hub. This circlip bearing will never see any saltwater.
You can also try ceramic or hybrid bearings. As i am not able to reach the bearings after final mounting i prefer ZZ over open ones.
After driving in salt water i flush it with fresh water and after a week driving in the mediteranien sea i put it in a sink with fresh water for a day and turn the motor sometimes. After drying i use some WD40 or caramba or whatever to maintain the surfaces.
You should use stainless screw to mount the prop but i have found no way to prevent corrosion when screwed in aluminium, maybe i try copper paste the next time.
Soaking the motor in corrosion-x is not safe, the windings are not secured against vibration, the iron is not protected well and environment is polluted. I prefer epoxy to make it maintainance free. Read my often linked thread to learn more about epoxying: Direct drive outrunner with direct water cooling.


#398

Fantastic explanation! Many thanks @PowerGlider for your effort.

Are you in touch with alien to propose 63100 disassembled? As it was in case if 100kv?


#399

Thanks everyone for your replies.
I guess I’ll try the 6384N PowerGlider Outrunner then. I thought about buying the APS 63100 as well, but it’s currently out of stock, not even on backorder, so I don’t know if and when it’ll be available again. I assume you don’t have any info on that, do you @PowerGlider ?
Other than that, thanks again for the detailed explanation, much appreciated. And yes, I’ve seen and read your instructions on how to epoxy the magnets, coils, etc… I will probably proceed just like you explained.
For the circlip, something like this will do right? https://www.maedler.de/Article/61741000
You use the circlip to prevent the bell+shaft+prop from flying off when you’re “braking” or off the throttle right? So it’ll just take the axial load backwards (opposite to the thrust to propel you forward).
APS offered me to custom-make a shaft, not sure how much that would cost me. I also have a lathe available, so I could just manufacture one on my own too.
The APS 80100 needs a 12mm shaft right? Did you guys build a custom shaft that goes from 12mm diameter inside the motor to 10mm to fit the propeller ?