Sorry, in english but you can answer in german or in french ! 
Hi all !
The Structil spar's weight in grams/meter is given by the formula :
[(D + d) x [D - d)] x 1.255, where :
D = outside diameter
d = inside diameter
For example, for a 8 mm O.D. spar : W = [(8 + 6) x (8 - 6)] x 1.255 = 35.1 g/m
On the Avia Sport website, I have seen that the .312 (8 mm) rod had a weight of 28.2 g/m... and for a 101 cm (40") spar.
Is that true ? No mistake ?
I thought that Avia was heavier than Structil ?
Thanks in advance, :H: