tail blade for trex 250 ( 40mm) massimiliano conti

To have the root even more resistant it is possible to insert in the hole a thickness of metal that you can find from this spare:Pale Tails for Trex 250 class. 40mm length and variable string for quicker response. They work very well I tested them in aggressive 3d flight and sports flight.
Recommended Material:
Z * Ultra ABS by Zortrax

or good quality Abs

or carbon filament

Layer thickness 0.09 or 0.14

Fan 2%
support 20%.
Infill Solid

To have the root even more resistant it is possible to insert in the hole a thickness of metal that you can find from this spare:

H25066A 
Tail Pitch Control Link