The Max Maker Build




So I connected my laptop and it almost got wrong. The test stand broke and the prop punctured my rain barrel. The “mast” was to weak and buckled. I need to use a stronger one. Luckily the laptop and the VESC stayed dry.

Anyway. I got the data below. This is at max throttle. Not enough probably. So now I am looking at my options. Scale the prop up or down?

Motor Current: 82A
Battery Current: 40A
ERPM: 16000 (can this be right?)
Thrust: 17-19 Kg

Erpm on load 16000
Erpm off load ? Just with prop in the air ( or without) be careful full rpm happens fast with current control

Batt at 40 motor at 80 , you are probably at 50% duty , 50% voltage , 1/2 rpm max , so downsize prop my guess , or add amp on motor

100kv 50v 7 poles (?) : 35000erpm …

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The VESC says 14 poles. So 16000/7 = 2300 RPM. Thats not quite enough. It spun in water only.

Since your Motor current limit is 82A, thats the reason for only 50% duty.
This means you max out torque of your motor at given amps limit.
Now you got some options:

  • higher current limit (so you get more torque out of the motor, will also heat the motor more, maybe kills it)
  • smaller Prop (will bring down the torque needed)
  • some sort of “gearbox” (will give more torque without adding strain on the motor)
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hi Max:
the .cad files can only be read. Could you pls send me the link in oder to be able to download? many tks in advance for you help !!

Max, are you still running that little out runner in a can from Alien power? I have had good luck this year running the 80100 in a can, but I have some mineral oil in the can with it to help keep it cool.

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Yes I am. I couldn’t even get it open. Its glued shut. What prop did you use? How much thrust did you get?

It’s glued with Sikaflex so its pretty hard to take apart. I have pulled mine apart and can take a look at which screw you can pull off and then pour oil into it.

@Jezza Thanks, but first I will try some more props. I might not use this motor after all.

@keby http://a360.co/2A9NB6A Does this work for you?

@Giga, the prop broke anyway, so I made a 10% smaller version. Will see how that goes. Maybe I get more thrust at the same amps.

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Regardless of the prop size, you need to try shed heat. Once the motor is running continuously for around 5 minutes it will have issues. There is absolutely no way for heat to escape from that motor. The one I tested got so hot that it bent the 3D printed mast clamp underwater and all the winding’s melted. I was lucky enough not to blow the ESC though.

I understand, but at this point I just want to get going once. Even just for 10 meters. I need to finish this video series and I would like to build a new board with everything I learned. One that is fully integrated and hollow. I am also hopeful to buy a direct drive that some people here have been testing as prototypes.

Today I installed the 120kV Flipsky motor. The VESC setup recommended 96A motor current. I limited it to 70A for now to be safe.

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I pushed mine up to 150A :rofl: :rofl: :rofl:

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Oh how cool is a video coming up soon?

What prop are you going to use?

I guess 70A will be much to less to get on the plane. I need about 110-130A motor current for lift of. Which Vesc are you going to use?

@Jezza: I am very worried about blowing up my VESC. I cannot sink much more money into this project. I need some success to continue and that is riding it.

@Felixfoiler: Depends how well the testing goes. I need the right prop and motor combination with enough thrust. Only then I can mount it onto my mast and actually try riding it on the water. At the moment I mounted this one: “Aluminium Propeller 7-1/4 x 5 for Yamaha 2 PS”.

@superlefax: I am using the VESC 6.0. 80A continuous, 120A bursts and I belive with bursts they mean 0.5 seconds, not 10. I cannot blow this thing up!

Ah I’m riding the 200A wavemaker vesc so can handle higher currents. Still need to get some vids and data for nick!

How are you mounting this prop onto this kind of shaft?

As long as you handle it correct (no water, no shortcircuits on logic), you cant break the VESC. The 120A are a thermal limit, as long as your cooling is good enough you can have 120A all day long.
Also the VESC will throttle down, as soon as you hit a thermal limit…

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Concerning trampa vesc , safety and max setting are pretty accurate I didn’t recorded at max 1A over the limit setting , but I understand and it is nice to see you back on the Efoil build
Temp and low voltage work nicely as well and reduce the power
The thing to remember is that you need speed for take off so rpm and the amp motor will go high at first for torque than go down when start fooling than go up again past 20-25km/h
Limiting to much the amp can get stuck in the area when you just don’t have enough speed to take off , so depending on your wing you will see if what is the best : 70A for 10-15sec or 90A for 5sec

The way I use vesc ( Ppm foc ) and feel free to correct me :
Motor / battery max setting
70A / 70A : not working spend to much time on surface
90A / 70A : better easier take off
130A / 60A : perfect , fun , nice kick at start
130A / 90A: to increase top speed

But I am using the 75/300 and FL motor … so the number will not be the same , it is just a exemple

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