A cool idea and a very functional design. It works great and the propellers fly high and far. The effort required is very moderate, so that even children can use it easily. My obstacles: I printed it in PLA at normal speed the first time. The dimensions were only just right. I had to press the axles in with a lot of force. The gears only ran with effort. The killer was the gearbox, where the planet didn't fit onto the gear band in the sleeve. Outside the tolerances. Somewhat frustrated, I started a second print. This time with PETG and at half speed. The result is FANTASTIC! Everything fits. All the gears run without force, the parts fit and everything works as intended. Great engineering work with that smoothy working gear and thanks for sharing! It's very appreciated.