Printed a new plane called the Bungee Prop. It’s a light weight (LW) PLA printed glider from 3D Labprint (https://3dlabprint.com/shop/bungee-prop/), with a wingspan of 1180mm. It’s a 3-channel setup, with throttle, rudder and elevator.
The files are designed to be printed in what’s called vase mode (or in the Cura slicer, ‘spiralize outer contour’). This means that each section is printed as one long spiral without the nozzle having to lift and travel between different parts of a layer. This makes a big difference for printing LW PLA, as this filament tends to ooze (or string) quite a bit during travel moves, which can leave quite a mess inside the part. The prints using this method are completely clear of stringing. In theory, if you had a tall enough printer, you could print the whole fuselage, and each wing, as one long spiral.
Print cost for the airframe was about $13 (approximately 220g of filament).
Maidened it today, and what an awesome flier! From the first launch it flew beautifully. Launches and landings were totally stress free, and upper air flying is great. It climbs really quickly even at about 50% throttle, and I even managed to find some thermal lift.
Low and slow flying is excellent, and it’s so stable. Hands-off flying is very impressive.
I don’t have any video of the first flights, but will post some very soon. If it helps, the flight video on the 3D Labprint website is very accurate, other than I found it more agile than expected. It turns/banks very well.
Some details:
AUW – 343g (a bit more than suggested by 3D Labprint )
Motor – Racerstar BR2304 1850KV
Prop – 8X4
Battery – 370mAh 3S Nanotech
2x Servos – 9g plastic gear
Printing and assembly was mostly pretty easy although I split the outer wing section into two prints, so I could print the last few cm’s at 0.15mm layer height. One other small problem was CA getting into one of the bowden tubes for the push rods when gluing the fuse. When trying to unblock this I snapped the fuse, but it was a simple matter to re-glue. The fuse feels flimsy, so to be safe I added some fibre tape near the tail section.
I like this plane so much I’ll print another very soon.
Cheers
Jeremy
