I said that is important to know the fundamentals of your profession on a practical application level.
Yes, and fundamentals of aircraft design is math. Of course it is desirable to have wide spectrum of knowledge (especially the ones related to field), but in a todays highly specialized world aerodynamicist doesnt need to know how to weld for example. Again, it would be probably good for him to know that as well, but that is not a professional requirement.
Homebuilding is a whole another story. We are much like aviation pioneers - we have to be pilots, engineers, welders, craftsmen, managers... - all in one; but because of that we are not building boeing but rather something that often resembles Bleriot XI - well, it depends on the overall skill of course.
As for practical versus theoretical argument, IMHO, a lot of really great airplanes have been designed by engineers that didn't know how to make the parts or even fly the plane, so I don't think a "requirement" is needed. By the same token, knowing how the parts or made or what it's like to fly an airplane can only give an engineera better perspective. More education in your field is always a good thing, I believe.
Exactly. I remember when I run across Job opportunities in Scaled Composites few years ago; among requirements were formal education titles (Msc, Bsc in engineering..), proficiency in 3D cad, experiences in CFD, and so on; and among DESIRED were pilots licence and airplane homebuilding experience.
Wouldn't be nice to have a tubular spar right on it (Bull's eye).
For all the forces combined , i mean. (structural strength)...
As Norman said tube is not good in bending as I-section is. A lot of wasted material in places we dont need it. Well, if we were limited to put single structural element in the wing, tubular section would be probably the one to choose; however in reality we can combine several structural elements to make an efficient composition. I-beam is good resisting bending, and rigid D-box or skin over entire wing is very good in torsion.