I want to share with you my balancing bird, working 100%!
Center of gravity works in different weight ratios. Part 1-2 low weight, parts 3-4 high weight.
The original bird modelled by Peter Behrens on http://archive3d.net/?a=download&id=58b6be71

My settings with CuraEngine

Nozzle 0.3
Filament 1.75
Layer Height 0.2
Top/Botton Thickness 0.4
Infill Overlap 15%
Suport Yes
Brim No
Raft No

Part 1 and Part 2
Shell Thickness 0.5mm
Infill Density 25%

Part 3 and Part 4
Shell Thickness 0.6mm
Infill Density 98%

Part_5_Tree_Stand Print as you want!

Very important!
To save the balance, after slicing
each part1/2 needs filament without suport and skirt: 1815mm +-10mm
and each part3/4 needs 4315mm +-10mm, if not, you need to change some settings.

RepRap

Prusa i3

No

Yes

How to connect the parts?

• Center Part1/2 with piece of filament and super glue
• Connect the two remaining parts to the space by using super glue

Good luck!