What superpower would you choose? Flight... doesn't everyone? I've been experimenting with hobby aircraft for over a decade and as recent advances in battery, motor, and power electronics technology has improved, my engineering skills have also grown to make personal flight a not 100% likelihood of death. I've been eager to try some electrical vehicle projects and this one turns out to be fairly affordable AND legal.
Please Note I've gotten P2 Paragliding certification. I have been designing, building, and crashing hobby aircraft for more than a decade so I have some vivid experiences of failure modes.
As I introduce my body to a DIY flying vehicle, the top concerns are currently:
- Motor entanglement during launch or flight, causing propeller to directly strike my body with high energy or the control lines of the paraglider: Safety Enclosure Design is Top Priority
- Control issue: Create several failsafes to cut power
- Battery Thermal Runaway: Create methods to jettison batteries
2016 to Current, More and More Research The scale of this project is informed primarily by conventional gas paramotors. They produce ~100-200lbs thrust, weigh ~50-80lbs, 25-40mph, and 20-50mi range. I also gathered details from light aircraft and other DIYers.
Version0 The objective of this prototype was to obtain the most immediate understanding of scale necessary for future stages of this project. I cobbled this together from spare RC parts and produced 12lbs Thrust.
Version1 Brushless motor at 2Kw and 24” propeller put out over 20lbs of thrust (the motor was capable of 5kW but I did not have an adequate ESC).
Among motor mounts and safety cage (not pictured), I designed and programmed the initial hand Throttle control. It has an emergency cutoff, shroud to only accept my hand, and a basic spring return.
Through my various other projects such as my eMTB, I have learned much more about battery requirements and making my own packs. This directly applies to this power project.
Fit test I dare not power this thing in-flight without a substantial propeller cage and more testing. However I could verify that it did not interfere with normal paraglider launch and handling
Interim Propeller cage permitted me to blast around on a longboard at 30mph and get a sense of the power. Not airworthy.
Version2 The frame is in progress. I sourced an affordable 20kW motor+ESC and with a 40” propeller is calculated to output 150lbs thrust, greatly exceeding the minimum target. Some motors need a gear-down but this motor has the torque capable and bearings to support direct drive. F’ YEAH! WOOHOO
Prototype parts are 3D printed on my modified home printer. I found some rapid machinists to cut the parts in metal when all the fitments have been confirmed and it’s ready to be final!
I have initiated designing this version with the propeller cage and employs Carbon tubing. My objective to make it quickly disassemble and the conical shape make its geometry a driver in Motor mounting, Pilot harness, COG placement.
Update 2-Feb-2019: I am in Finland during spring2019 accompanying my wife on her Fulbright research and cannot ship batteries or my paraglider :( I will continue this project when we return and I hope to be able to perform test flights by oct2019. In the meantime I’m experimenting with other things…. SNOW THINGS!
Update 25-June-2019: I’ve been playing a lot with composites. My original plan was to custom machine the modular parts. This is substantial weight and cost… I’m now considering carbon composite over 3D printed form. The trick will be to ensure sufficient adhesion, perhaps by creating a porous surface. In my prior experience corona discharge also increased bonding due to high surface energy. Feel free to comment if you have tips!
Update 2024: Project has been on the backburner- I have two kids now! I’ve had a few sketchy instances free-flight paragliding in recent years and it takes quite a bit more time to maintain sharp piloting skills than I can commit to at this time. I want to pick this up again soon- I’d also like to evaluate using several smaller motors rather than the large single motor configuration.