EPPG1 design

Discussion of design theory and construction techniques for paramotors, paragliders and related accessories and equipment.
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Primal Flight
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EPPG1 design

Post by Primal Flight » Fri Aug 16, 2019 5:54 pm

So I am designing an electric paramotor...not sure why, I love my EOS150 powered parajet zenith, but I think an electric would be easier for those quick flights (possibly after works), or maybe easier to take along on a road trip with the family. no stinky gas in the car, etc....Or maybe it's that I have always loved electric power systems, since my RC plane, heli, and drone days (still have some planes and multicopters).

Of course I have looked at the OpenPPG project (https://openppg.com/) and downloaded the model files etc. but I don't like the small props. there are bigger props and motors to turn them available now. In fact that is where my journey began....The power system.

The plan is to use 30"x8" props (762mm) turned by 100KV 9235 motors. Of course fitting those huge props into a frame is the tough part. They have to be overlapping. and the mounting points are in very different spots than the standard openPPG motors, so it is not a simple drop in....I was thinking of designing a whole new frame, but I suspect modifying the openPPG frame to mount the new motors will be a faster and simpler way to get into the air. I have started to design all new arms, for the open PPG, but may rig something up with the existing arms if I can get a bare frame ordered. (which I might be ordering soon). Maybe I will eventually end up designing a whole new frame...not sure at this point.
EPPG1 DESIGN ASSEMBLY1.jpg
Prop overlap1.jpg
of course, these large props will not allow the arms to fold so that feature of the openPPG is lost. I have an idea for removable arms that may work, and would still allow for packing it up in a car.

The motors with the 30" props make 11kg (24.25lbs) of thrust on 12S with 46 amps of current. so all 4 will be 44kg (97lbs) at 92 amps...and I already have this 250A 14S capable speed controller. Also the mounting system for the props allows them to be doubled up for 4 blades each, but I will have to do some testing on those. Another variable is the overlapping props, not sure how that will affect thrust efficiency.
Image

Toby
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Primal Flight
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Posts: 45
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Re: EPPG1 design

Post by Primal Flight » Fri Aug 16, 2019 6:19 pm

I also posted this on the OpenPPG community here: https://community.openppg.com/t/openppg ... s-mod/1938

One concern is I may be under-powered with only 44kg of thrust. (top 80 is 50kg of thrust for comparison). some options are 4 blade props, which should increase the amp draw and give a little more thrust. Another thought is just go with 6 motors, or perhaps even 8, but both of those will require very different mounting systems. The motors are not rated for 14S, but that may be another option.

interesting mod of propellers, and explanation of thrust.

Primal Flight
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Posts: 45
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Re: EPPG1 design

Post by Primal Flight » Sat Aug 24, 2019 2:29 pm

Next step is the motor test stand. Need to see what these motors can do.....i didn't have one, so i built one from stuff i had laying around and some drawer slides from the hardware store.
I had most of the electronics put together from a previous ground vehicle project.
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Primal Flight
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Re: EPPG1 design

Post by Primal Flight » Sun Aug 25, 2019 8:00 pm

preliminary thrust test results match what is expected. 4 blades gave about 20% more thrust, but the amperage went up as expected, (in the 60s, and very hot motor).
I will update with real numbers soon.

The real question is what to do with the paramotor. 11kg x 4 is less than a top80, and with the prop overlap it is likely to be 10 to 20% less.
6 motors would do it, but that gets big. Another thought was doubling the motors up, basically connecting 2 together (mechanically).....leaning toward 6 props/motors.

interesting battery capacity calculator. designed for ground vehicles, but full of variables that can be tweaked. https://battery.real.engineering/

Primal Flight
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Re: EPPG1 design

Post by Primal Flight » Thu Aug 29, 2019 9:18 pm

Coupling the motors just adds to much complexity, and weight, while not adding more air affecting area. Area is king, so more props are the better choice.....going for 6 motors.

still figuring out the mounting , but I got the overlap stager figured out. I am ignoring the hoop right now, next goal is a thrust test prototype, so no protection needed.
It will be taller than most paramotors, but the width won't be much more than the Parajet Zenith.
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