BlimpDrive: An electric paramotor for self-launching and sustaining soaring flights
This is a quick description of a quick project. If I make another one I'll do a few things differently, and mainly for this reason I'm not going to post precise design information on the mechanical structure. This said, those with the skill set to put something like this together will be able to self-identify, build something like this by filling in the blanks, and hopefully improve on the version described here.
1/1/22: I added a builders' forum over at Sky's Edge
My goal here was to make something I'd be able to attach to my pre-existing paragliding equipment. That is, something that wouldn't require a dedicated harness and a dedicated wing, and think this satisfies that goal nicely. My secondary goal was for it to be quiet, and I'm pretty happy in that hearing protection is not required or desirable. I do have something in mind for a truly-whisper quiet paramotor in the future, which will be an altogether different concept.
If your main interest is soaring more than motoring, as mine is, this kind of thing can be used for self-launching (getting up to an altitude where natural lift might be used), or for sustaining (extending soaring fights while searching for lift or crossing gaps). The endurance with my 710Wh LiPo battery is about 14 minutes as tested, which is a factor of three better than I expected.
8X Aluminum U-Bolts:
* Description: 1/4-20 Aluminum, 2" ID
* Exemplar: McMaster-Carr P/N 3035T16
* Price: $3.48/ea = $34.80
* Description: 32 x 11 carbon fiber, CW/CCW matched pair
* Exemplar: T-Motor G32X11
* Price: $388.77 per set
* Description: 130KV, 5.659kW BLDC, 118A peak, 10-14S
* Exemplar: T-Motor U13 Ⅱ KV130
* Price: $379.90/ea = $825.53
* Description: 180A, 6-14S
* Exemplar: T-Motor Flame 180A HV
* Price: $299.95/ea = $599.90
* Description: 16Ah, 12S, 15C
* Exemplar: Tattu TA-PLUS1.0-15C-16000-12S1P-AS150
* Comes with two extra pigtailed mating connectors (use one for paramotor and one to make the charging cable) * Price: $646.49 after S/H
1X 5V DC-DC Converter (i.e. "BEC") 1X 5V DC-DC Converter (i.e.
*Built into ESCs. Only 1 5V pin is broken out to throttle unit
* Description: 12S Balance Charger
* Exemplar: SKYRC PC1260
* Price: $332.99
* Ardiuno Nano + Pot. + 3D printing
* I have a detailed CAD assembly of this, but not sure I want to share it yet
1X Carbon Fiber Tube
* Made from scratch. Improvement needed with carabiner connecting points
- Would likely interfere with reserve deployment, but I have some ideas about this.
- Considering as it can currently produce ~100lbs of thrust, the
thought occurs that with another 50lbs of thrust the drive has
enough power to lift me and my gear directly
Perhaps a future development, which would require a lot of R&D, would be to have behave as a propulsive emergency fall-arrest device. This might require cyclic control on the props.
- Drone props are optimized for static thrust/lift. Would be nice to experiment with different (higher) pitches and diameters more easily. Use R/C helicopter hub w/ collective control for testing?
- Could fit the same battery capacity _within_ the tube using round cells. Would have to handle battery management and break out each cell for charging, though.
- The carabiner grabbers could be easier to use. Switch to some kind of hinged arrangement? Or a single bolt/thumb screw on each 'biner?
- In making a new tube from scratch, would like to integrate the motor and maybe the ESC mounts right into the structure