Hi all. Newbie here, not to PPG but electronic PPG specifically. I’ve built electronic skateboards, racing drones of all sizes, so my knowledge of motors propellers, ESCs is already there.
Is there anyone who can summarise what an optimal 2 motor setup would look like right now? I’m aware that the preference is 4 motor, but I have a personal reason to try 2 for the time being.
I’m generally interested in making the setup as light weight as possible, but with the ability for just a few good climbs, so high amp draw for most of the usage. would be cruising with low or zero throttle, and looking to use folding blades. Already working on an openPPG frame.
Thanks all! Looking forward to joining the community.
Given that the props are rotating within a circular cage, four make better use of the space than two could do. Arguably, six could be even more efficient. The size of props fitting within such a frame, however, produces a higher pitch noise than a single prop-pair spanning the same circle. OpenPPG has suggested that such a single 2-blade prop (or 3-blade) could be more power efficient, though it produces yaw as power changes. The multiplicity of props allows counter-rotation to cancel such effects. I wonder if blade-shaping, say with tapered scimitarred ends, might address the issue of energy wasted as sound. And I haven’t yet read here of anyone experimenting with various battery types. I believe the “standard” Bonkas are LiPo. But perhaps Li-ion or Li-S could be better due to greater energy densities. Other possibilities include supercapacitors, but I suspect that they may not be commercially available yet. A number of folks here seem to have the capabilities for DIY modifications to the OpenPPG models that have been produced as available products so far.
Coaxial?
If your going to a two motor and prop setup for torque elimination and maximizing propeller efficiency then perhaps going to a coaxial system would work. There would be slightly higher bearing losses on the prop shafts. The cage could be smaller which means safer ground handling. Folding coaxial propellers would be a trick.