Wake Turbulence behind an A-380

In article ,
"Morgans" wrote:

"Frank Ch. Eigler" wrote

But imagine the mass of smoke agent that would have to be dispensed in
order for it to be visible 5-10 miles behind the jet. There would be
a terrific amount of dilution through the air, moving at that kind of
speed.

Not to disagree with the fact that putting smoke systems on heavies would be
a bad idea, but I do wonder about how much smoke would have to be used.

I remember a few years ago at OSH, there was an older jet trainer (don't
remember which type) that had smoke generators carefully place on the
wingtips. The trail was tight, and spun fiercely for a very long time. ( 2
or more minutes?) I was fascinated.

That's actually what keeps the plane in the air.

See http://www.av8n.com/how/htm/airfoils...ation-vortices

rg

"Ron Garret" wrote

That's actually what keeps the plane in the air.

Very incompletely, and incorrectly stated.
--
Jim in NC

On Thu, 24 Nov 2005 at 08:56:56 in message
, Ron Garret
wrote:

That's actually what keeps the plane in the air.

See http://www.av8n.com/how/htm/airfoils...ation-vortices

rg

That is a good article. I would partially disagree in that he minimises
viscosity of the air as a factor. True it is small, however if the air
had no viscosity then there would be no circulation and hence no lift.
He actually shows diagrams without circulation which produce no lift.

The necessity of viscosity was demonstrated by Jean le Rond d'Alembert.
In fact he did painstaking mathematics, without recognising viscosity,
and failed to be able to show why there should be any forces on a body
in an airflow at all. He went to his grave a puzzled and dissatisfied
man.

That is d'Alembert's Paradox.
--
David CL Francis