The answer to this question varies depending upon how fast you want to
go. All bets are off once you start looking a compressible flow and its
effects (roughly sonic velocity). For the speeds that most homebuilts
experience, the rounded shape promotes laminar flow around most of the
shape and hence lower drag for a wide variety of angles of attack. The
problem with the "eye shape" is that the point will start developing
turbulent flow at the point at very low angles of attack. This
turbulent flow will cause a lot of drag. Even gear fairings have angle
of attack issues during some flight regimes, steep climb, slips, etc.
As far as a vertical stab, your control surfaces are the last thing you
want to have behind a turbulent flow transition as they need clean air
to be effective.

Play around with dragging some different shapes at various angles of
attack through a tub of water and you'll see the effect very clearly.

Dave

Jay wrote:

I've been wondering which shape is lower drag, a rounded one or a
sharp one. I can understand why the leading edge of a wing would be
rounded, this allows a larger range of AOA before flow speration and
stall, but what about the vertical stabilizer? Wouldn't this be
better with a sharp leading edge?

When the air hits a blunt leading edge it has to accelerate quickly to
get out of the way. At the very front, the molecules are actually
moving in a direction normal to the direction of travel of the wing.
This has got to cause drag. If the edge were sharp and the air didn't
have to react as quickly to displace, this would seem to cause less
drag.

I know that the tear drop shape is the lowest energy state, but it may
not be the lowest drag shape. I'm thinking that an eye shape may be
better for many profiles.

So I see tear drop shape profiles all over on struts, whell pants,
vertical stabilizer, etc. Looking for explanations other than "Thats
what everybody does, so they couldn't be wrong."

Regards