Electric Hydrofoil/E-Foil

Hiorth · Jul 26, 2017

notafraidtotry said:
Hiorth said:

ropower86 said:

I am looking to purchase a Neugart Planetary GearBox. I know the ple 40 gearbox I need to choose but which gear ration do I need to get?

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We ordered the PLE 40-005 (5:1) ratio. Which will give us about 4000 rpm on the propeller (unloaded), and probably less (around 3-3500 in real life). Lower rpm with bigger prop gives higher effciancy, on the other side, too large prop may result in torque overload for gearbox/motor and may pull air more easily if it gets to close to the surface.

Pacifimeister used Parker 7:1 and it worked. The neugart PLE and the Parker pv40 gearbox is mechanically more or less the same so an ratio in that ballpark with correct prop should work.

Click to expand...

Can I ask where you ordered the PLE 40 from and how much you got it for? I have been looking in the UK but couldn't find an online distributor.

Thanks......

Just sent them an email directly from their webpage https://www.neugart.com/en/ and a guy from Norway (my country) contacted me by mail. Paid 200Euros +sale tax per piece, bought 2 pieces. Going to make more boards with improved design once we get the first setup up running.

Cheers.

Hiorth · Jul 26, 2017

ropower86 said:
Hiorth said:

ropower86 said:

I am looking to purchase a Neugart Planetary GearBox. I know the ple 40 gearbox I need to choose but which gear ration do I need to get?

Click to expand...

We ordered the PLE 40-005 (5:1) ratio. Which will give us about 4000 rpm on the propeller (unloaded), and probably less (around 3-3500 in real life). Lower rpm with bigger prop gives higher effciancy, on the other side, too large prop may result in torque overload for gearbox/motor and may pull air more easily if it gets to close to the surface.

Pacifimeister used Parker 7:1 and it worked. The neugart PLE and the Parker pv40 gearbox is mechanically more or less the same so an ratio in that ballpark with correct prop should work.

Click to expand...

There is a Neugart company 6 miles from me in Charlotte North Carolina. What do you think about the PLE 40-008, would that do the job too?

I would advice you to choose 5:1 gearing. The reason for this is the rated output torque that you can read in the PLE 40 spec (see below). The gears are ideal in size when gearing 4:1 and 5:1, and will probably last longer, as we will push them to their limit.

ropower86 · Jul 26, 2017

Hey guys, I found a site where you can calculate your motor efficiency. This is really important because we need numbers.

http://www.bavaria-direct.co.za/constants/

Note: Just scroll down to the bottom of the page.

ropower86 · Jul 26, 2017

staska said:
ropower86 said:

******* ATTENTION *******

This is a warning to all, DO NOT BUY GEARBOX THAT IS MADE IN CHINA! They are made out of low alloy and gears will break under load. That is why their gearbox is cheap and it will not work for our project.

Click to expand...

+100 same experience. You are not flying on it. But it make you hurt if broke at bad moment.

Yep. No cutting corners, it's like building an airplane.

Jezza · Jul 26, 2017

Hiorth said:
Jezza said:

I thought I'd throw in some progress pictures as I have almost completed the test parts phase and can then move into making the final parts.

View attachment 1

View attachment 2

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Nice! Looks real good with no edges onto the tube. Will you glue it in? Or use o rings and screws?

Initially I will use O-rings and screws. But if the water tests show any sign of leaking I will probably add glue.

notafraidtotry · Jul 26, 2017

Jezza said:
I thought I'd throw in some progress pictures as I have almost completed the test parts phase and can then move into making the final parts.

Looks very good. Can you share more details when you have time. Would you be happy to share the CAD/STL files too?

staska · Jul 27, 2017

Jezza said:
What exactly do you class as an industrial planetary gearbox and industrial brushless?

"Robust by design", calculated to work 24/7 for few years with some / regularly maintenance. For gearbox - it is calculated not to transfer static load, but for dynamic/inertial load - like going on full rpm, and stucking prop - all rotor inertia try to broke an gearbox. And few times in a row. Same for motor/controller. And measured and tested.

For esc - if motor is stuck fast enougth, di/dt (current) will rise faster than protection could detect it to close mosfet. Tried this by purpose on some cheap chineese esc - all blow up.

I tried to built an electric paramotor - You could do with quite cheap outrunners from turnigy - but if done propertly - it costs at least 10 times more. Got few quotas from industrial motor suppliers, and they was almost 8 times the price, and 2 times weight. And if you need a prop to run at normal rpm like in 2500-3500 range on 10 kw - it will have bigger than penny sized tooth-gear.

Hiorth · Jul 27, 2017

Jezza said:
Hiorth said:

Jezza said:

I thought I'd throw in some progress pictures as I have almost completed the test parts phase and can then move into making the final parts.

View attachment 1

View attachment 2

Click to expand...

Nice! Looks real good with no edges onto the tube. Will you glue it in? Or use o rings and screws?

Click to expand...

Initially I will use O-rings and screws. But if the water tests show any sign of leaking I will probably add glue.

I suppose thr joint closest to the mast will be most crucial.

Great, we will go for somethink like this on the next itteration, Already ordered sls 3d prints. Thinking about getting everything machined in aluminium later on with a polished finish. Will have to change the design alot tho.

Jezza · Jul 27, 2017

notafraidtotry said:
Jezza said:

I thought I'd throw in some progress pictures as I have almost completed the test parts phase and can then move into making the final parts.

Click to expand...

Looks very good. Can you share more details when you have time. Would you be happy to share the CAD/STL files too?

I wont share prints until I am happy with the design. I think it makes sense to test and know it works first and it will also save others money.

Hiorth said:
Jezza said:

Hiorth said:

Jezza said:

I suppose thr joint closest to the mast will be most crucial.

Great, we will go for somethink like this on the next itteration, Already ordered sls 3d prints. Thinking about getting everything machined in aluminium later on with a polished finish. Will have to change the design alot tho.

Click to expand...

Click to expand...

Click to expand...

I will most definitely be machining the spacer between the motor and gearbox out of aluminium. It will also help transfer heat to the outer casing and make the whole unit a heat sink. I should have my O-rings today or tomorrow so will be able to test how well the unit seals.

Hiorth · Jul 27, 2017

I will also share 3d files, but I agree with jezza. Would like to test everything first.

Will machine aluminium motor/gearbox mount as well. I have a small cnc router that handles aluminium, so will do it on monday

. Will also machine an aluminium rib that goes around the gearbox to heatsink it directly to the outer alu-tube.

notafraidtotry · Jul 27, 2017

Hiorth said:
I will also share 3d files, but I agree with jezza. Would like to test everything first.

Will machine aluminium motor/gearbox mount as well. I have a small cnc router that handles aluminium, so will do it on monday . Will also machine an aluminium rib that goes around the gearbox to heatsink it directly to the outer alu-tube.

Great. I am collecting the carbon fibre cloth and resin this Saturday so hoping to start laminating the 3D Printed foil next week.

staska · Jul 27, 2017

Did any one have good drawing for slow/stable/easy foil ? I do have access to big cnc router, could cut them from plywood and laminate. Found some calculations for hydrofoil boats, but not for boards..

dirkdiggler · Jul 27, 2017

I'd love to see that work on the slingshot foil mast. I've got the wakesurf foil from slingshot myself. Seems like a good way to get out a DIY kit, so people could clamp the motor/prop to the mast. Kind of like how the eskateboard movement got going.

I'm going to try a ghetto foil design hopefully this weekend and see how things work. I'll post if I get any worthwhile results.

Did any one have good drawing for slow/stable/easy foil ? I do have access to big cnc router, could cut them from plywood and laminate. Found some calculations for hydrofoil boats, but not for boards..

Amazing to me how wood is no longer used much in at least the prototyping stage. Here's a video from 6 years ago with a homemade wood foil. Seems to work well enough. Cheesy video, but you get the idea. I've heard about Clearwater foils, but no direct experience with them. $1500 foils seems a bit much for what you are actually paying for.
[youtube]pWNvY_8krWg[/youtube]

staska · Jul 27, 2017

I was loking into this https://crazyfoil.com/product/crazy-foil-2017-ex-002/ plain, rectangular foil with speed data important for us. Also - have seen an plywood kit somethere..

Jezza · Jul 28, 2017

staska said:
Did any one have good drawing for slow/stable/easy foil ? I do have access to big cnc router, could cut them from plywood and laminate. Found some calculations for hydrofoil boats, but not for boards..

Here is a pretty complete write-up: https://www.seabreeze.com.au/News/Kitesurfing/How-to-make-your-own-Hydrofoil_8649403.aspx
You could always increase the size of the front wing to give more lift at a slower speed.

And if you really want to save a lot of time, use an old skateboard deck: https://www.seabreeze.com.au/forums/Kitesurfing/General/DIY-hydrofoil-with-rubbish-and-an-angle-grinder?page=1

fechter · Jul 28, 2017

After watching the video, it seems there's a pretty steep learning curve to riding one of those things.

Carbon fiber would probably be the best material for the foil. Keeping the cross sections thin will minimize drag. Even aluminum might not be bad.

aethyr · Jul 28, 2017

Just following this thread, as I'm interested in building one. I built an electric kick scooter that is loads of fun on land, and now its on to water

A few questions. I see that there is discussion of using a gearbox - is that to keep RPM at target or mostly due to sync issues? Is sync basically an issue of insufficient starting torque or something else? I couldn't find whether you guys are having sync issues running sensored or sensorless. I had sync issues when starting from stopped on my scooter when running sensorless and with gearing/motor kv optimized for speed rather than torque. When I switched to a much larger motor and ran sensored, I was able to start from stopped with ease.

So I guess my question is, why not simply rewind the motor at a much lower kv, say 50kv or so and increase voltage? If you have a 200kv motor, rewound to 50kv, you've essentially gone 4:1 with no loss in energy from the gears.

My plan is to use a sensored alien tp100, which is supposedly rated at 12kw continuous, at 72kv and then use one of his 300A EV escs and a 20s20p battery pack. The tp100 is a 100mm motor, so that's pretty wide, but I think it will be worth it for the substantial increase in torque/power?

dirty_d · Jul 28, 2017

I guess this is a good first step. I think I'll worry about learning how to ride behind a boat before I start thinking too hard of about the electric propulsion.

parabellum · Jul 28, 2017

aethyr said:
Is sync basically an issue of insufficient starting torque or something else? I couldn't find whether you guys are having sync issues running sensored or sensorless. I had sync issues when starting from stopped on my scooter when running sensorless and with gearing/motor kv optimized for speed rather than torque. When I switched to a much larger motor and ran sensored, I was able to start from stopped with ease.

It is result of using crappy hobby ESCs and motors, go sensor type, e-bike controller and real motors with needed thermal mass and continuous performance, that will work stone hard a day log without sweat at 2-3lbs "penalty". I am already little disappointed of some things discussed here, it is similar to discussions of 2010-2015 on ES, gearboxes, ESCs, hobby motors, ets. End result always was, stay out of all that kids stuff.

Gege2000 · Jul 28, 2017

aethyr said:
Just following this thread, as I'm interested in building one. I built an electric kick scooter that is loads of fun on land, and now its on to water

A few questions. I see that there is discussion of using a gearbox - is that to keep RPM at target or mostly due to sync issues? Is sync basically an issue of insufficient starting torque or something else? I couldn't find whether you guys are having sync issues running sensored or sensorless. I had sync issues when starting from stopped on my scooter when running sensorless and with gearing/motor kv optimized for speed rather than torque. When I switched to a much larger motor and ran sensored, I was able to start from stopped with ease.

So I guess my question is, why not simply rewind the motor at a much lower kv, say 50kv or so and increase voltage? If you have a 200kv motor, rewound to 50kv, you've essentially gone 4:1 with no loss in energy from the gears.

My plan is to use a sensored alien tp100, which is supposedly rated at 12kw continuous, at 72kv and then use one of his 300A EV escs and a 20s20p battery pack. The tp100 is a 100mm motor, so that's pretty wide, but I think it will be worth it for the substantial increase in torque/power?

It seems like it's a problem of torque efficiency at low kV and a problem of weight and size. With a direct drive, the motor will be too big and too heavy for the good torque and rpm.

parabellum · Jul 28, 2017

LFP said once, invest the weight of gearbox in active materials of the motor, go right topology and go DD, it is more efficient and more thermal mass to take overshoots. By now, there is no perfect motor to get what is needed for this task, but also no cheap controller to correct motor deficiencies. Again, gearbox is just a cheap short-cut to adjust possibilities to needs, paying with efficiencies. Maybe Miles could design the perfect motor for this task, so we stop seeing comments and mentions about gearboxes.

aethyr · Jul 29, 2017

parabellum said:
aethyr said:

Is sync basically an issue of insufficient starting torque or something else? I couldn't find whether you guys are having sync issues running sensored or sensorless. I had sync issues when starting from stopped on my scooter when running sensorless and with gearing/motor kv optimized for speed rather than torque. When I switched to a much larger motor and ran sensored, I was able to start from stopped with ease.

Click to expand...

It is result of using crappy hobby ESCs and motors, go sensor type, e-bike controller and real motors with needed thermal mass and continuous performance, that will work stone hard a day log without sweat at 2-3lbs "penalty". I am already little disappointed of some things discussed here, it is similar to discussions of 2010-2015 on ES, gearboxes, ESCs, hobby motors, ets. End result always was, stay out of all that kids stuff.

What you're saying is simply to not use an underpowered motor and esc. I think that's a given. But you're not providing any information as to WHY some experienced cogging issues.

I don't think "real" motors have to simply be large motors to handle high, sustained current. They can also use more advanced magnets that can handle higher heat - this gets you a smaller motor, like an astro motor, which, incidentally has been used in e-bike applications. And that smaller profile is especially important in an e-foil/surfboard where a much larger motor is impractical because of increased drag.

aethyr · Jul 29, 2017

Gege2000 said:
aethyr said:

Just following this thread, as I'm interested in building one. I built an electric kick scooter that is loads of fun on land, and now its on to water

A few questions. I see that there is discussion of using a gearbox - is that to keep RPM at target or mostly due to sync issues? Is sync basically an issue of insufficient starting torque or something else? I couldn't find whether you guys are having sync issues running sensored or sensorless. I had sync issues when starting from stopped on my scooter when running sensorless and with gearing/motor kv optimized for speed rather than torque. When I switched to a much larger motor and ran sensored, I was able to start from stopped with ease.

So I guess my question is, why not simply rewind the motor at a much lower kv, say 50kv or so and increase voltage? If you have a 200kv motor, rewound to 50kv, you've essentially gone 4:1 with no loss in energy from the gears.

My plan is to use a sensored alien tp100, which is supposedly rated at 12kw continuous, at 72kv and then use one of his 300A EV escs and a 20s20p battery pack. The tp100 is a 100mm motor, so that's pretty wide, but I think it will be worth it for the substantial increase in torque/power?

Click to expand...

It seems like it's a problem of torque efficiency at low kV and a problem of weight and size. With a direct drive, the motor will be too big and too heavy for the good torque and rpm.

Not sure I understand/agree here. Why does lowering kv change the weight and size of a motor? Doesn't a lower kv simply increases torque at the cost of top end rpm, which is exactly what mechanical gearing does, but without the additional cost of the gearing itself, both in weight and efficiency? You simply have to provide more voltage, but consequently, inversely proportionally less current, resulting in the same exact wattage.

staska · Jul 29, 2017

parabellum said:
s. End result always was, stay out of all that kids stuff.

This is human psychology - we want it better and for free

Jezza · Jul 29, 2017

parabellum said:
LFP said once, invest the weight of gearbox in active materials of the motor, go right topology and go DD, it is more efficient and more thermal mass to take overshoots. By now, there is no perfect motor to get what is needed for this task, but also no cheap controller to correct motor deficiencies. Again, gearbox is just a cheap short-cut to adjust possibilities to needs, paying with efficiencies. Maybe Miles could design the perfect motor for this task, so we stop seeing comments and mentions about gearboxes.

Who's LFP?
A gearbox is not a cheap shortcut. It completely alters the dynamics and motor requirements, bringing down cost, weight and maximizing a motors power curve. If this wasn't the case, then no boats would use gearboxes, Torqeedo would not use gearboxes on their electric range. The application of an electric motor to a boat is very different to that of a skateboard, ebike or car.

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