High altitude flutter - Vne

I don't know if anybody has used tapered pultruded rods in a spar as
well but it may be a possibility given the complex rods and tube shape
being manufactured for other applications.

Rectangular profiles are made, the smaller the cross section of the
Pulltrusion the better you are able to match the bending moment. Naturally
it is more effort to built with smaller sections
but it provides for a near optimum spar.
Udo