GM> JE> I'm a bit puzzled. How is the hollow core  going to
GM> JE> dissipate heat when the hollow itself traps the heat inside
GM> JE> itself?

GM>A hollow conductor of the same current carrying capacity as a
GM>solid one has a greater surface area per unit length.

GM>Compare these two:
GM>                               SOLID  HOLLOW
GM>Outer diameter                  2.5     4.0     inches
GM>Overall area                    2.0    12.6     sq.inches
GM>diameter of hollow centre       0       3.67    inches
GM>area of hollow centre           0      10.6     sq.inches
GM>area of conductor               2.0     2.0     sq.inches
GM>outside circumpherence          7.85    12.56   inches
GM>surface area per 1 ft. length  94.2    150.7    sq.inches

GM>So the hollow conductor has an outer surface area, and hence the
GM>ability to dissipate heat, more than 50% greater than the solid
GM>one.

Hmmm. I really never thought of it that way.
Jay

GM>This has used no extra metal, hence no increase in weight, since
GM>the cross sectional area of the metallic part is the same.

GM>The only penalty is an increase in wind resistance, but that can
GM>be reduced by flattening the hollow tube into an oval. If the
GM>height of the oval is the same as the diameter of the solid
GM>conductor, the resistance to wind from the side is actually less
GM>than the round solid conductor due to streamlining effect of the
GM>oval shape.




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