expresstechonsite wrote:

... The reason I ask is because I keep thinking that if we
once made airframes out of wood, then wouldn't PVC be just about as
strong and more durable (long lasting?).


Many woods have an excellent (small) wieght to strength ratio, much
better than PVC. But where wood really excels over plastics in
general is the weight to _stiffness_ ratio.

Strength determines how much force is needed to
permanently deform something. Stiffness determines
how much something deforms elastically (meaning it
rebounds to its original shape when the force is removed)
for a given force.

There are a number of other material properties relevant
to the issue of airplane construction as well.

That said, I have seen photos of a light plane made from
aluminum ladders. One segment was used for the wing,
another for the horizontal stabilizer and another for the
fuselage. The fuselage had another, shorter segment
stacked onto the other where the wing was joined,
sort of like a leaf spring.

--

FF