I just found this MAD M 40 motor so instead of using 4 smaller motors how about this
motor it would be much more efficient and simpler to build and could probably use the same frame with a few changes . It puts out 175 lbs of thrust at 200 Amps at 100v with a 47 in prop.
Todd
You did not do your research on the 4 motor setup — no torque!
cheers
AND smaller cheaper props. And it folds up nicely with 4 props. And the amps are distributed across 4 ESCs so each one gets a 1/4 of the overall amps.
Might gain a little efficiency but probably very little.
I am just looking at several options to convert my gas ppg over to electric.
A single M 40 spinning a large 47” prop.
should be the most efficient I think?
Or 2 M30 with counter rotating props.
Or 4 smaller M10 .
They all have there advantages and disadvantages.
I have a 60 “ diameter cage so I could fit 4 28 or 29 “ props which would help with efficiency a little bit.
If you already have a gas frame then a single motor makes more sense. I say go for it! We would love to see your results!
Our cage is 60 inches and we can barely fit four 22 inch props. You can’t put four 30 inch circles inside of a 60 inch circle without overlapping. If you do overlap you would lose efficiency.
One big prop would give the best efficiency but then you have torque. But you’re probably used to having torque.
Having flown my 2stroke gas paramotor for almost two years, and the openPPG for two very short flights (the weather has been really shitty, after I am done with my battery…) I can already confirm that the OpenPPG “feels” much better in terms of no torque and no vibration.
Since the battery on the openPPG is also way higher than the gas tank on the 2stroke, it also feels better when carrying it on my back.
However, the torque on the 2stroke is not that much of an issue, I have to admit!!
The efficiency gain will be from a larger prop and is probably significant.
Unclear if the motor or ESC itself is dramatically more efficient than 4 smaller. I suspect there is some advantage, but maybe small compared to the prop change.
I actually think this is a good option for someone converting to electric on a conventional frame.
Advantages:
Disadvantages:
You could run four 6S packs in series to make the correct voltage. However, if you wanted more capacity you’d be forces to run 8 packs (4S2p).
I am thinking this is more of an advantage than a dis - higher voltage allows for smaller wiring and increased efficiencies. Yes, things over 24volts have the potential to kill so caution is always common sense when working with electrons!
Cheers
Good point. Yeah, current is much lower.
I just think in terms of automotive. 50V is the cut off between HV and not.
I’m a 300lb guy with high flying ambitions (Mauna Loa is over 10k feet), so the trade off of torque effect (and Gyroscopic Precession) is looking worthwhile given the increased torque a single larger prop can produce vs. 4 smaller props. (At the same time, if I could have no effect, the idea of a larger engine producing more effect isn’t exactly top of my list)
If I can make the prop narrow, it will be fine for me from a compactness perspective… my main goal on that front is that it can go in the back of an SUV, and that I can fly with it on a plane.
200 amps at 100v would be 20000Wh (20Kw), which other commercial EPPG designs claim produces between 75-80 kg of thrust or so. That should be pretty solid I believe.
Elsewhere in the forums, someone linked to Alien Power Systems who makes a wide range of motors up to 45Kw! All that torque from an electric motor… that just sounds scary to me. I’ll take 4 props or a contra-rotating prop with that order please! 
This MAD M40 motor looks ideal! I have been considering trying a Hobby King Turnigy 150cc motor, but I don’t think it would be powerful enough for a single prop, and would also require a reduction belt drive.
But this motor looks ideal for direct drive of a 125cm prop (like the Atom80 Helix).
Seriously considering using it on a P2F LAF frame.
Fed up of waiting for the OPPG to become available…
Not to revive a dead thread, but from what I have seen the sp140 motor looks the same as a Mad M40. From what I have seen the M40 does look a lot higher quality than most other Chinese high power motors.
My guess is they will use the MAD M40 pro V 3.0 KV43 (15KW)…
If these test parameters are correct and we use 31 kg thrust for a 85 kg pilot at level flight then it will average ca. 4900 watts.
Run_time(min) = Capacity(Ah) / Current(A) x 60min/hr
Capacity: 40 Ah 24s
Current: 50.4A
Run_time = 40/50.4 x 60 = 47.6 min. flight time
In comparison to other ePPG 85 kg pilot:
6350 watts avg. 18 KW OpenPPG X4
4662 watts avg. 18 KW Paracell simplify
4300 watts avg. 12 KW Hacker Q150 Thomas Brandstetter custom
With 2455 RPM at level flight and a 47 inch Propeller the tip speed will be over 550 km/h / the same tip speed the X4 has.
I don’t know if the SP 140 will use this motor, but these would be the numbers with this motor.
A few things. On a big wing you don’t need that much power to fly. You only need about 13kg thrust. You can’t really go off of those thrust numbers because they are static thrust so in flight those thrust numbers will be lower. Also the motor is capable of running a 51" prop which is a lot more efficient than the 47" prop that it was thrust tested with which will change things.
Based on the paracell with their 72Ah battery pack (14s24p lg hg2 cells or 30q cells based on age) you could theoretically fly off less 3700w power. You would probably never see this number in real life, but it’s based on them only getting 60 minutes and they have gotten 70 with it so it may actually be realistic. I don’t know.
Based on this I am 90% sure that the SP140 motor is the M40
This is a screenshot taken from a video of the SP140.
This is a M40 motor.
I know the resolution is bad on the screenshot from the video but I got a better one on my computer and it’s much easier to tell that they are the same.
How did you come up with that number? Seems awful low…
If you have an all up weight of 225lb and an overall 8:1 glide ratio you only need 28.125lb thrust or roughly 12.6kg thrust to fly. (225*1/8=28.125)
8:1 is awfully optimistic. A lot of A wings won’t even do that with a free flight harness. A 6:1 or 5:1 L/D is more realistic for a PPG setup. Obviously this is all theoretical, but if you design your motor setup assuming you’re going to get an 8:1 L/D in flight you are going to end up disappointed.
That would be with a very large and high glide ratio wing to keep you minimize drag from the frame. With a realistic size wing you won’t get an 8:1. Even if you did go with a 6:1 glide ratio your still looking at only 37.5lb thrust needed. I do believe many modern wings have a glide ratio over 12:1 so with a VERY large and low speed wing you could even see higher than 8:1. It entirely depends on your frame and wing.
