Pipefather,

A tapered wing is more efficient than an untapered wing in that
it suffers from less induced drag. Induced drag is generally only
important when the wing is operating at a high coefficient of lift.
For example, when a pylon plane is in a high-G turn, induced drag
is very important. For a plane with reasonable wing loading, induced
drag is not a huge deal for most flying.

Induced drag is minimum when the lift is distributed elliptically along
the span of the wing. A tapered wing can give a decent approximation
of an elliptical lift distribution, but can also be more subject to tip
stall. Keeping the chord at the tip above about 60% of the chort at
the root can avoid a really nasty tendency toward tip stall, and still
give some induced drag reduction.

In addition to possibly allowing intentional tip stalls, tapered wings
can allow rolls to be faster, which is one reason you might see them
on pattern planes.

banktoturn