40kW paramotor project

[Hyperious]

Hey all, long time no see.

I'm in the process of building an electric paramotor.

I started flying about 2 years ago on a 2-stroke and now have well over 200hrs of airtime. That said I've always wanted to go electric, and finally with my new job making time for and giving me the equipment to, I've started the conversion process for my old frame from gas to electric.

Right now I'm targeting 40kW max power, with 27kw continuous output. I want to make this thing into a slalom/sunset ripper. The biggest limiting factor of course is batteries, and I plan on using a 24s2p pack of 16000mah 6S packs that are rated for 25C. Total 32Ah of storage at 100v full charge.

My question is what ESC's out there would be the best for this application? I can easily source a Curtis F6 controller that will do what I need since I work for Curtis now, but the weight is high, and software is still in development for driving sensorless applications. Honnestly I'd like to just use a bigass ESC for control since it's just spinning a prop and doesn't need ultra-precise RPM control.

I'm already using a 154mm stator 20 pole outrunner wound to 40kv for power, which should give me about 20% more RPM than my 2-stroke with a ton more torque, but ESC/controller-wise I'm kind of stuck. I've seen some stuff from Flier RC that may work, but I've also seen that they top-out at 25kw based on testing done by members here.

Any advice? should I just stick with a 96v 450A curtis F6?

 

[thepronghorn]

I would probably just use a Curtis if I worked for them.

Open PPG is using an APD esc in the SP140 kit.

 

[Ecyclist]

How is you project going? Any progress?

 

[Two4Seven SuprDan]

how about the BAC8000?

 

[Ecyclist]

BAC8000 is 72V max. He is looking for a controller that can handle 100V.

 

[Jackal21]

Hi, did you finish your paramotor? What motor, esc, battery did you use? I've just made my electric paramotor with the Mad M50 motor, Mad 300A esc and a li ion 32A 88v nominal 2.8kwh battery and I love it. Some details in the video of my first flight

 

[Ecyclist]

A fantastic job. Congratulations!
Can you post how much thrust does your build produce?
Thanks.

 

[Jackal21]

A fantastic job. Congratulations!
Can you post how much thrust does your build produce?
Thanks.

Thank you!
The Mad M50 motor is considered to produce about 70kg thrust with the 140cm prop at 20kw, info found on the OpenPpg community forum.
With my battery I can go to about 15kw, above that the voltage drop is to high. So I have maybe 50 kg thrust. All I know is that recently I had a flight and at 10kw I had 2.7 - 3 m/s climb, more than I need. I usualy climb slowly with 0.7 - 1m/s at 5-6kw.

 

[Ecyclist]

Thank you for the info.

 

[nicobie]

Pls be careful!

Nice job!

 

[Jackal21]

With the help of a friend I've managed to lighten my electric paramotor with 11kg from 36 to 25kg and still have the 30min flight time. Now it's a dream to fly! I've changed the 2.8kwh 32Ah 88v 17kg (2.5kg alu case, 13kg the cells) 21700 battery with a 30Ah 9kg semi solid lithium batt, that gives me same flight time of 30min but is 8kg less. Also the M50 4.2kg motor with the V135L 2.2kg motor and motor plate with a cnc lighter one.
Works fantastic, brings me so much fun and want to encourage others to try it so check it out!

 

[fechter]

That looks great! Nice landing.

 

[Logic11]

With the help of a friend I've managed to lighten my electric paramotor with 11kg from 36 to 25kg and still have the 30min flight time. Now it's a dream to fly! I've changed the 2.8kwh 32Ah 88v 17kg (2.5kg alu case, 13kg the cells) 21700 battery with a 30Ah 9kg semi solid lithium batt, that gives me same flight time of 30min but is 8kg less. Also the M50 4.2kg motor with the V135L 2.2kg motor and motor plate with a cnc lighter one.
Works fantastic, brings me so much fun and want to encourage others to try it so check it out!

Nice!
If you want to further improve it; try aerofoil, elliptical tubing for the safety frame:
Like this:

Or this:

Round Bar/pipe Cd: ~1.17
Aero teardrop (wing) shape Cd: 0.045 (26X lower than round)

You will notice a decrease in prop noise too. (see: Blade passing Stator noise)

A pusher prop spinner like this might also be worth a try:

It adds a bit of weight, but the aero and motor cooling advantages may make it worthwhile.

The NTX Spinner

NB that both ideas are easy and safe to try with some hot wire and Styrofoam ingenuity. For science!
(If some Styrofoam falls off during testing; it wont hurt or break anything)

 

[Jackal21]

Nice!
If you want to further improve it; try aerofoil, elliptical tubing for the safety frame:
Like this:

Or this:

Round Bar/pipe Cd: ~1.17
Aero teardrop (wing) shape Cd: 0.045 (26X lower than round)

You will notice a decrease in prop noise too. (see: Blade passing Stator noise)

A pusher prop spinner like this might also be worth a try:

It adds a bit of weight, but the aero and motor cooling advantages may make it worthwhile.

The NTX Spinner

NB that both ideas are easy and safe to try with some hot wire and Styrofoam ingenuity. For science!
(If some Styrofoam falls off during testing; it wont hurt or break anything)

Thank you for your interest! I thought about adding eliptical shape stirofoam around the prop ring but because I keep those semi circles that form the ring in a bag for transport, something too soft won't last. Plus the net is on the ring so it would have to pass through those eliptical shapes somehow.
But I saw that some companies make eliptical shaped rings now.
Those carbon spiners look awesome, I have one on my 27% rc gas plane. But, in order to take it off I have to unscrew those tiny bolts around it and it takes time.
Interesting points thought, thanks!

 

[Otto44]

Hello Jackal, Very nice work! I want to build one too, already talked to MAD. They suggest the M 30 Motor as suitable for PPG. Which motor are you using now?

 

[Jackal21]

Hello Jackal, Very nice work! I want to build one too, already talked to MAD. They suggest the M 30 Motor as suitable for PPG. Which motor are you using now?

Hi, sorry for the so very late reply, the forum did't noticed me via e-mail and I didn't check the forum until now.
I'm curently using the V135L from MAD and used the M50 from them. The M50 is the base for paramotors, is a powerfull motor and used with succes by the Openppg on their SP140 paramotor.

The V135L works for light and conservative pilots, as it has half the mass of the M50 but I can't really recommend it because I did some modifications to mine to keep it cooler and still I have to pay attention to it and not go beyond 6kw power for long.
What makes these two motors, mostly the M50 suitable it's first of all their low 34kv(rpm/volt) managing to swing big props 130-140cm thus being efficient and worth considering.

The M30 sugested to you I see it has 80/100kv, that's a too high rpm resulting in the usage of small props like the 40 inch (100cm) prop recomanded for the M30. That's way too small. Beside that I see it's a 12-14s (44-52v) motor. Again, that's not enough. The ones I've mentioned are 24s (88v) motors.

It seems to me that MAD has no ideea of what power paramotors need.
You see, if you're like 70kg body weight and you'll fly an slow efficient wing, like I am/do, you'll need like 3.4-3.7kw power to keep level flight and about 5-7kw to slowly climb.
At such low voltage, you'll need to compensate with Amps and quickly go beyond the 63A limit they are stating.
Then you have to consider the motor's ability to sustain a certain power, in the case of the M30 that is max 15kg. That won't fly a person. Maybe with a very efficient setup but no power for climbing.

As you can see in their chart bellow, at the max recommended Amps of 63 you'll barely have the power to mentain level flight at 3.8kw.
And at the recommended 15kg thrust (the power that this motor can sustain for long) you only have 2kw power, not even close for level flight.

I Hope this helps, although it might be to late.
Looking forward to hear what's the status of your project.

Best wishes
Marius

 

[Otto44]

Hello Jackal,

thanks for the answer. I bought a Scout Zero, which I would like to convert to electric. So as I understood, the V135L is not a good choice? Seems to be a little on the weak side concernimng torque. Maybe the AM 40 is a better choice, weight is in between the 135 and 50.
Can you tell me more about your cells? I want to use pouch cells, from the maker we use for our powertool batteries. They can deliver high currents with good voltage stability.

 

[Jackal21]

Yes, the AM40 seems a good choice. It has the 34kv(rpm) option that can swing 140-150cm props. It has centrifugal cooling like the V135 so I'm not sure if it has as good cooling as the more opened M50 but being bigger than the V135 it might stay cool.

For now I fly my old battery pack made of 21700 cylindrical cells. It works nice.
I had a good and light semi solid pouch cell pack but because I didn't protect it well enough, at a rough landing, the phisical shock killed it. Pouch cells went bad.
So if I would start again, I would go the pouch cell route because of building simplicity and low weight but I would protect it better through both rigid plates of some kind but mostly with squishy 3cm foam under it.
Pouch cells have the positive terminal of aluminum and the negative of nickel. While nickel can be soldered, you'll have to find another way for connecting the aluminum terminal because aluminum soldering, although possible it's complicated.
I've thought about a sandwitch consisting of a nickel plate on which cables can be easely soldered and some thicker 1.5mm aluminum plates with the aluminum terminal in the middle, all of them bolted together.
First you need to think how big of a battery you would want depending of what weight you want it to be.
The voltage needs to be 24s 88v nominal, so you only have to choose the Amps.
You can see both my batt specs on posts on this thread. An 30Amp pack will result in a 2.6Kwh batt that might offer somewhere between 20-30min flight time depending on your weight and wing used.
For that you want 30A cells, so you'll have 24 cells to connect. While with cylindrical cells I had to spot weld 192 cells because one cell has 4Amps.
With high end semisolid pouch lithium cells, a 30Ah batt might be like 9kg, while pouch lipo 30Ah might go to 13kg. Or you might find other options too.
If you bought a paramotor I get it that you are familiar with them, maybe flown them or paragliding?
When I start I had hundreds of questions and found many answers by reading tens of threads for months on openppg forum before starting to build. If you need a more detailed talk we can do it on whatsApp. We can share details about that on email if you want. Otherwise here is fine too just very slow.

 

[Otto44]

Thanks for the further input. Yes I am flying already, but not with motor so far. i will get my scout zero in February.

Concerning pouch cells, i can get them with both terminals in nickel. Our supplier has a 29Ah cell, which I already use in my efoils. So battery wise thewre will be no problem, as we develop such here. For me it is just about the motor. But not urgent. i will start fyling the Zero with the Atom 80 , and later will try to convert it to electric. How can we establish the whatsApp?

 

[Jackal21]

Oh, you're in the game allready, that's cool
I'llsend you a pm.

 

[A-DamW]

Oh, you're in the game allready, that's cool
Just write me on my e-mail:

Just a suggestion, might want to edit your post and remove your email, bots are pretty good at scraping = lots of spam for you.
You could send your email via private message.

 

[Jackal21]

Just a suggestion, might want to edit your post and remove your email, bots are pretty good at scraping = lots of spam for you.
You could send your email via private message.

Oh, right. Thanks