The center board has been glued with HK CA glue (HC-50-175). A small frame with screws through the four beam holder holes kept the sandwich layers aligned.
Note: Better do large areas with this glue outside as it generates a fume.
Using nylon spacers and screws, the top and bottom sandwich were assembled.
The beams were machined with a 1/32″ flat end mill and cut to length in the last run.
M3 nylon screws lock the beams and act as breaking point when crashing.
To attach the electronics to the center board, I chose two different approaches. Components which will not be used in every flight have been attached using Velcro. The other components were glued directly to capton tape I put to the center board. The ESCs were wrapped in capton tape to prevent short circuits. I hope the heat dissipation is reasonably low with the 30A ESCs.
- HK CA glue (HC-50-175)
- Loctite Vinyl, Fabric & Plastic Flexible Adhesive
- HK 30min Slow Cure Epoxy
- 3M General Purpose 45 Spray Adhesive
Sandwich Bend Test
- 100x10mm x 1mm CFK, 3mm Fill, 1mm CFK
CFK 1mm, 3k plain weave carbon, orientation parallel (0°/90°) to centerline
Bend test showed best adhesion and no separation up to 6kg for HK CA glue (HC-50-175). All other separated well below this (usually at around 3-4kg). However glueing is tricky for large areas such as the center board.
During the first flights, the flight time was reasonably high at a bit over one hour with 1555 props.
Arms folded away during the first crash (I’d love to call it unplanned rapid decent though :-)) and the M3 nylon screws broke as planned, preventing damages to the rest of the drone.
With this setup, flight times above one hour have been achieved, even including the 180g 3-axis gimbal and GoPro.
In the diagram below various test flights for a 15″ 5.5 and 17″ 6.0 propeller were aggregated to show the effect the prop choice has on flight time.
Update: I’ve updated the battery with a 6600mAh 6S and the quad flies a lot more stable now.
Previously the flight recorder showed motors occasionally maxing out during sharp moves or wind gusts.
I’ll do some test flights and check the flight time. First flight was 2500mAh for 15min
Bill of Material
|6||rctimer 5010 360kv||NA|
|3||Multistar Lipo Pack XT90||Amazon|
|4||1760 Folding Props||Ebay|
|1||Flight Controller and Power Module||Hobbyking|
|1||GPS witd Compass||Amazon|
|1||Folding GPS Antenna Base/Black||Ebay|
|1||Lipo Voltage Checker||Amazon|
|1||Skyfpv Video Switch||NA|
|1||FPV 3 Axis CNC Metal Brushless Gimbal With Controller For DJI Phantom GoPro 3 4||Banggood|