As your image shows, Kw corresponds to HP which is a measurement of (I believe) work “done”… with a given power motor, you will get a specific return of thrust assuming you use the optimal efficiency setup.
In the PPG world, I’m no expert, but I have observed many experts recommend caps around 20HP for a 90KG or so pilot flying at sea level, and not doing acro. The reasoning I am familiar with is that you must achieve a certain speed to convert thrust / forward inertia into lift. Heavier pilots need larger wings which creates more drag to achieve the same lift ratio, and therefor requires more thrust to increase lift rates. The more power you apply in both electrical applications, and in aerodynamics, the more resistance you have to overcome, and the less efficient everything becomes. For this reason, in order to gain an adequate climb rate to safely gain elevation to clear your launch site’s obstacles, you need to achieve a target amount of thrust.
Of course, if you want to launch off a cliff, and don’t care about climbing or compensating for down-drafts, you could calculate the exact thrust needed to maintain lift, or, if you have a large enough launch site, you can tolerate a slower climb rate. If you have an undersized motor, however, it will burn out faster, and be far less efficient.
With the single prop things will become more efficient, and a smaller motor will do the same job. When dual carbon batteries hit the market, we’ll really see a world of changes 
Do you have the final specifications for the battery pack? Would it be possible to use it on the x4 with other motors ?
The battery for the SP140 is a 24s (100v) system so its not compatible.
Have you considered converting the X4 to 24s?
50/60 volts for the X4 Yes. The X4 is a bit on the edge as for the power discharge rate needed. The X4 would just need a very large Li-Ion cell count to get a long lasting cycle life. So it for sure could work but its not really in the sweet spot.
I’m going to do a 10 day training course later this month. Then I will have to decide what to buy and when. I would really prefer this electric single prop over a two-stroke. And I’d be willing to wait a bit for it. But only a few months.
I don’t expect you to be announcing a delivery date. I just need some guidance. Would you recommend that I go ahead and buy a two-stroke? Or wait for this new version?
Thanks!
Any update on pre ordering the sp140?
I found the answer to my question, I guess. “The SP140 paramotor is expected to start shipping early Spring”.
What are the:
- Motor
- ESC
with the single prop unit? 
Hi Paul,
very interested in your single prop unit, more specificaly for efficency reasons. Living in Europ, we have good paramotor manufacturer. I would be very interested in your new system you came up, though i would be courious to know if the electrique propulsion system could be installed on different kind of cages. Right now, i could purchase a very light weight cage over here and then install your system. I also have a very advised battery supplier over here who can build battery packs of any kind, this on your specifications. These are all small things that could help me save costs from shipping overseas. Thanks for your fantastic job in this project.
Best greatings.
Laurent
Wing Acquired, Helmet built, training starting in March. SP140 status?
They said late spring. Use the school equipment for training. Good luck with your training. Let us know how it goes.
Sounds like progress to me . I am very interested in an electric ppg as the cost of petrol in the UK and Europe is extortionate .
This would be neat possibility in the future. People could have smaller barrier upgrading to electric if pre-existing frames could be used. This both reduces the costs and gives room for preference. If compatible motor mountings existed for common engine manufacturers, then upgrade could ideally be something like an engine swap. Though it would still be quite a DIY project to attach the battery pack and all the electronics.
I’m flying a batch 4 X4 and I love it but I’m pretty sure most para pilots would not consider a sub one hour cruise time as an upgrade.
Hi, I’m a beginner on e-ppg, but i have years of experience with gas pgg, flying from 80cc to 185cc at different take off weight. I confirm that it is enough 10Kw (or 14Hp) to have lot of fun !
What I can’t understand is why , if it is possible to obtain 10kw from a direct drive, in youtube I have seen lots of project with pulley reduction…
I have understood that the max rpm with no load = KV x Vcc, but this limit is really reachable ?
And what happens if I apply a resistant torque ? Which is the relation between max rpm and max torque ? I guess Power=Torque x 2pi x rpm/60 … But evidently it isn’t, because at the same power same project uses pulley reduction insted a lower KV…
It has to do with brushless motor efficiency. A lot of the cheaper motors are inefficient at the relatively low RPM required for the propeller to be efficient. They will run much cooler turning at a faster RPM at the same power level.
I have been looking to build an electric paramotor. What I have found is that often the motor KVs are too low for running a 15s lipo/li-ion battery. I can get a motor down in the 27kv range and with 55.5v It peaks at 1500rpm without any load!
When you see the reduction drive they are most often using older motors. I am not positive but I believe that highly efficient low kv motors have more recent become a viable option as computer simulations and stronger magnets at a lower cost have become available. Also on top of that any moving part has efficiency losses. So by removing the reduction drive you can increase your flight time.
Any Specs yet?
Cheers
Hey Mr. White. Will the SP140 be open source or only for purchase?
Thanks,
Grant