Aerodynamic Drag

Mike Rapoport wrote:
Eanest:

How about a related question? On my Helio Courier the fusilage/wing
intersection is slightly less than 90deg. The intersection looks like an
aerodynamic disaster. How much drag would be eliminated with a fairing than
can only come down the fusilage three inches? How about a two part fairing
(one part would be on the door) that could come down 6 inches?


Mike, I think you are mistaking me for someone who knows what they are
talking about.

Seriously, though, I read a NACA report from the LARC site a while back
describing an experiment with fairings on a high wing aircraft. I can't
remember all the particulars, and a quick search just now proved
fruitless, but I remember that they realized significant speed gains
with increased fairing sizes. In my *opinion*, the more fairing you can
get the better.

Consider the right wing. The problem with intersection drag is that you
have the air being compressed both from the left off of the fuselage and
up from the wing. Down there in the corner, the poor air doesn't know
which way to go. So like FEMA or a southern city mayor, it chooses to
spin around in circles. We call these vortices, and they eat up a lot
of energy without producing anything. A fairing, even a small one, will
help direct the air, and stop the spinning, at least partly.

Tell you what, Mike, why don't you try and experiment? Roll up a few
sheets of newspaper for filler, and temporarily duct tape in a 3"
fairing. Fly the plane and measure the before and after speeds. It
would make a nice Sport Aviation article.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."

Thanks. I will try the experiment this winter (or at least I intend to try
it ). In addition to the Helio, I have a MU-2 which has large radius
fairings between the wing and fusilage. On the right side of the Helio
there is plenty of room for the fairing to come down the side of the
fusilage before it reaches the window but on the left side the door
restricts the fairing size. It is surprising to me that Helio left the area
unfaired.

Mike

"Ernest Christley" wrote in message
om...
Mike Rapoport wrote:
Eanest:

How about a related question? On my Helio Courier the fusilage/wing
intersection is slightly less than 90deg. The intersection looks like an
aerodynamic disaster. How much drag would be eliminated with a fairing
than can only come down the fusilage three inches? How about a two part
fairing (one part would be on the door) that could come down 6 inches?


Mike, I think you are mistaking me for someone who knows what they are
talking about.

Seriously, though, I read a NACA report from the LARC site a while back
describing an experiment with fairings on a high wing aircraft. I can't
remember all the particulars, and a quick search just now proved
fruitless, but I remember that they realized significant speed gains with
increased fairing sizes. In my *opinion*, the more fairing you can get
the better.

Consider the right wing. The problem with intersection drag is that you
have the air being compressed both from the left off of the fuselage and
up from the wing. Down there in the corner, the poor air doesn't know
which way to go. So like FEMA or a southern city mayor, it chooses to
spin around in circles. We call these vortices, and they eat up a lot of
energy without producing anything. A fairing, even a small one, will help
direct the air, and stop the spinning, at least partly.

Tell you what, Mike, why don't you try and experiment? Roll up a few
sheets of newspaper for filler, and temporarily duct tape in a 3" fairing.
Fly the plane and measure the before and after speeds. It would make a
nice Sport Aviation article.

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."