You can do best with a combination.

Composites can make complex shapes and be used to make a slicker yet lighter
fuselage, but if you use a simple airfoil, it is tough to build lighter than
an aluminum wing without getting expensive.

A lot also depends on what speed the plane will be cruising at. The higher
the speed, the more important to be slick.

I would be interested to know at what speed do wing rivets really start to
hurt vs. the extra weight of a normal homebuilt composite wing. I would be
willing to take one of our more experience builder's best guess.



"John C" wrote in message
...
I know this gets talked about all the time...but I have aquestion I was
hoping someone smarter than me could help me with.

An aluminum evangelist showed me this link:
http://www.aerotalk.com/myth_02.cfm

The author asserts that:
" The ratio of empty to gross weight is one of the most telling measures
of
structural efficiency.
The equations are basic:EMPTY WEIGHT + PAYLOAD = GROSS WEIGHT

Reduce empty weight by 100 lbs and the pilot can load an extra 100 lbs of
payload, fuel/ baggage/ people.

EMPTY WEIGHT/GROSS WEIGHT = WEIGHT EFFICIENCY RATIO

The lower the ratio, the more efficient the design."

He goes on to use this determination of strength/weight (or, structural
efficiency) to determine that composites do not offer a greater
strength/weight ration in airframe construction applications.

But then I read about the new 7E7, which is a largely composite aircraft,
thus lighter, thus more efficient.

How do I reconcile these conflicting pieces of information?