You notice the power of the vortice when you're an impatient number 2
to a heavy taking off.
The slower and heavier the A/C the bigger and more powerful the vortice

You notice the power of the vortice when you're an impatient number 2
to a heavy taking off.
The slower and heavier the A/C the bigger and more powerful the vortice

You notice the power of the vortice when you're an impatient number 2
to a heavy taking off.
The slower and heavier the A/C the bigger and more powerful the vortice

Jack Harrison wrote:
"Michael Mcneil" wrote in message
news:9009dc8b5fe10d00759c8646af9396ec.45219@mygate .mailgate.org...
No, it's not about the mess a £4 like Spencer Hines is making on
s.m.n.

Does anyone on here know the diameter of condensation trails of
aircraft?

How do they vary with size of plane, height, humidity and speed? If
a
rough correspondence to the wing diameter could be given, that
would be
enough for me to gauge it.


I am a retired airline pilot. I do have to say that I could never of
course
see my own contrails. The nearest I got to seeing my own was as
shadows on
the ground or on cloud below me. But I did plenty of contrails made
by
other aircraft.



The trail is initially produced some distance (circa a few tens to a
hundred
metres) behind the engines. It is the engines that provides the
hygroscopic
nuclei on which the condensation can occur.



Then other factors come into play. All aircraft produces vortices
from the
wing tips. These affect the contrail and result in the swirling
pattern
that can often be seen when close. From the ground, this rotation is
hard
to observe (try binoculars) so tends to show itself as a serrated
pattern.

I've noticed when sitting in a windowseat by the wing on a plane, that
what look like mini-contrails emanate backwards from the wing. Smoke
from the engines, or is this the "vortices"?

Often on a clear day, when looking up at a plane with a contrail from
the ground, I can spot the gap between the plane and the start of the
trail.






The next step depends on numerous factors. Often in very dry air,
the trail
quickly dissipates - it appears as a very short trail, often looking
like a
needle with an eye (the eye being the divided trail from the pair or
the
four engines). But when conditions are just right, the injection of
these
condensation nuclei can be the trigger for yet more condensation to
occur
and the trail spreads laterally and becomes persistent. It can be
many
times wider than the aircraft that initially produced it and can last
for a
very long time.

I've noticed at least 3 types of contrail from the ground. One the
"needle" you mention, another a longer, wider version of it where you
can see the division in the middle, this persists and widens for
several minutes then vanishes, and one that refuses to dissipate, just
spreads out and ends up turning into what looks like cirrostratus. I've
seen a lot of the latter type just lately- this is the type I think
might be meddling with the weather (though I shan't go into that here).


Edmund

Jack Harrison wrote:
"Michael Mcneil" wrote in message
news:9009dc8b5fe10d00759c8646af9396ec.45219@mygate .mailgate.org...
No, it's not about the mess a £4 like Spencer Hines is making on
s.m.n.

Does anyone on here know the diameter of condensation trails of
aircraft?

How do they vary with size of plane, height, humidity and speed? If
a
rough correspondence to the wing diameter could be given, that
would be
enough for me to gauge it.


I am a retired airline pilot. I do have to say that I could never of
course
see my own contrails. The nearest I got to seeing my own was as
shadows on
the ground or on cloud below me. But I did plenty of contrails made
by
other aircraft.



The trail is initially produced some distance (circa a few tens to a
hundred
metres) behind the engines. It is the engines that provides the
hygroscopic
nuclei on which the condensation can occur.



Then other factors come into play. All aircraft produces vortices
from the
wing tips. These affect the contrail and result in the swirling
pattern
that can often be seen when close. From the ground, this rotation is
hard
to observe (try binoculars) so tends to show itself as a serrated
pattern.

I've noticed when sitting in a windowseat by the wing on a plane, that
what look like mini-contrails emanate backwards from the wing. Smoke
from the engines, or is this the "vortices"?

Often on a clear day, when looking up at a plane with a contrail from
the ground, I can spot the gap between the plane and the start of the
trail.






The next step depends on numerous factors. Often in very dry air,
the trail
quickly dissipates - it appears as a very short trail, often looking
like a
needle with an eye (the eye being the divided trail from the pair or
the
four engines). But when conditions are just right, the injection of
these
condensation nuclei can be the trigger for yet more condensation to
occur
and the trail spreads laterally and becomes persistent. It can be
many
times wider than the aircraft that initially produced it and can last
for a
very long time.

I've noticed at least 3 types of contrail from the ground. One the
"needle" you mention, another a longer, wider version of it where you
can see the division in the middle, this persists and widens for
several minutes then vanishes, and one that refuses to dissipate, just
spreads out and ends up turning into what looks like cirrostratus. I've
seen a lot of the latter type just lately- this is the type I think
might be meddling with the weather (though I shan't go into that here).


Edmund

Jack Harrison wrote:
"Michael Mcneil" wrote in message
news:9009dc8b5fe10d00759c8646af9396ec.45219@mygate .mailgate.org...
No, it's not about the mess a £4 like Spencer Hines is making on
s.m.n.

Does anyone on here know the diameter of condensation trails of
aircraft?

How do they vary with size of plane, height, humidity and speed? If
a
rough correspondence to the wing diameter could be given, that
would be
enough for me to gauge it.


I am a retired airline pilot. I do have to say that I could never of
course
see my own contrails. The nearest I got to seeing my own was as
shadows on
the ground or on cloud below me. But I did plenty of contrails made
by
other aircraft.



The trail is initially produced some distance (circa a few tens to a
hundred
metres) behind the engines. It is the engines that provides the
hygroscopic
nuclei on which the condensation can occur.



Then other factors come into play. All aircraft produces vortices
from the
wing tips. These affect the contrail and result in the swirling
pattern
that can often be seen when close. From the ground, this rotation is
hard
to observe (try binoculars) so tends to show itself as a serrated
pattern.

I've noticed when sitting in a windowseat by the wing on a plane, that
what look like mini-contrails emanate backwards from the wing. Smoke
from the engines, or is this the "vortices"?

Often on a clear day, when looking up at a plane with a contrail from
the ground, I can spot the gap between the plane and the start of the
trail.






The next step depends on numerous factors. Often in very dry air,
the trail
quickly dissipates - it appears as a very short trail, often looking
like a
needle with an eye (the eye being the divided trail from the pair or
the
four engines). But when conditions are just right, the injection of
these
condensation nuclei can be the trigger for yet more condensation to
occur
and the trail spreads laterally and becomes persistent. It can be
many
times wider than the aircraft that initially produced it and can last
for a
very long time.

I've noticed at least 3 types of contrail from the ground. One the
"needle" you mention, another a longer, wider version of it where you
can see the division in the middle, this persists and widens for
several minutes then vanishes, and one that refuses to dissipate, just
spreads out and ends up turning into what looks like cirrostratus. I've
seen a lot of the latter type just lately- this is the type I think
might be meddling with the weather (though I shan't go into that here).


Edmund

"Edmund Lewis" wrote in message
ups.com

I've noticed at least 3 types of contrail from the ground. One the
"needle" you mention, another a longer, wider version of it where you
can see the division in the middle, this persists and widens for
several minutes then vanishes, and one that refuses to dissipate, just
spreads out and ends up turning into what looks like cirrostratus. I've
seen a lot of the latter type just lately- this is the type I think
might be meddling with the weather (though I shan't go into that here).

Quite common on the approach route to Manchester Airport over a region
that is noted for its dry (by UK standards) micro-climate.

The region is a 6 mile triangle of flats once marsh sea-shore surrounded
by low hills and is given to mists.

On sunny days these trails will last forever it seems.

When an aircraft passes through air that is nearly saturated the
vortices of the air it displaces must be equal to the mass of the craft.
Complex aerodynamics reduced to simple physics is that the air supports
the wings and the wings support the plane.

The pressure changes alone must be enough to cause condensation but as
with the vortices themselves the process is adiabatic or self contained.
If the weather was going to cloud over anyway then these things would
have formed anyway.

However some bean counters have suggested that the overall picture is
that aircraft take out the high and low points.

What that ammount to is that while overall temperature change is small
there in less movement in the thermometer.

Or not as the case may be.

At least that is what I gather from the study of the temperatures over
places like New York after the attack shut down all the airports in the
USA.



--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

"Edmund Lewis" wrote in message
ups.com

I've noticed at least 3 types of contrail from the ground. One the
"needle" you mention, another a longer, wider version of it where you
can see the division in the middle, this persists and widens for
several minutes then vanishes, and one that refuses to dissipate, just
spreads out and ends up turning into what looks like cirrostratus. I've
seen a lot of the latter type just lately- this is the type I think
might be meddling with the weather (though I shan't go into that here).

Quite common on the approach route to Manchester Airport over a region
that is noted for its dry (by UK standards) micro-climate.

The region is a 6 mile triangle of flats once marsh sea-shore surrounded
by low hills and is given to mists.

On sunny days these trails will last forever it seems.

When an aircraft passes through air that is nearly saturated the
vortices of the air it displaces must be equal to the mass of the craft.
Complex aerodynamics reduced to simple physics is that the air supports
the wings and the wings support the plane.

The pressure changes alone must be enough to cause condensation but as
with the vortices themselves the process is adiabatic or self contained.
If the weather was going to cloud over anyway then these things would
have formed anyway.

However some bean counters have suggested that the overall picture is
that aircraft take out the high and low points.

What that ammount to is that while overall temperature change is small
there in less movement in the thermometer.

Or not as the case may be.

At least that is what I gather from the study of the temperatures over
places like New York after the attack shut down all the airports in the
USA.



--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

"Edmund Lewis" wrote in message
ups.com

I've noticed at least 3 types of contrail from the ground. One the
"needle" you mention, another a longer, wider version of it where you
can see the division in the middle, this persists and widens for
several minutes then vanishes, and one that refuses to dissipate, just
spreads out and ends up turning into what looks like cirrostratus. I've
seen a lot of the latter type just lately- this is the type I think
might be meddling with the weather (though I shan't go into that here).

Quite common on the approach route to Manchester Airport over a region
that is noted for its dry (by UK standards) micro-climate.

The region is a 6 mile triangle of flats once marsh sea-shore surrounded
by low hills and is given to mists.

On sunny days these trails will last forever it seems.

When an aircraft passes through air that is nearly saturated the
vortices of the air it displaces must be equal to the mass of the craft.
Complex aerodynamics reduced to simple physics is that the air supports
the wings and the wings support the plane.

The pressure changes alone must be enough to cause condensation but as
with the vortices themselves the process is adiabatic or self contained.
If the weather was going to cloud over anyway then these things would
have formed anyway.

However some bean counters have suggested that the overall picture is
that aircraft take out the high and low points.

What that ammount to is that while overall temperature change is small
there in less movement in the thermometer.

Or not as the case may be.

At least that is what I gather from the study of the temperatures over
places like New York after the attack shut down all the airports in the
USA.



--
Posted via Mailgate.ORG Server - http://www.Mailgate.ORG

Michael Mcneil wrote:
"Edmund Lewis" wrote in message
ups.com

I've noticed at least 3 types of contrail from the ground. One the
"needle" you mention, another a longer, wider version of it where
you
can see the division in the middle, this persists and widens for
several minutes then vanishes, and one that refuses to dissipate,
just
spreads out and ends up turning into what looks like cirrostratus.
I've
seen a lot of the latter type just lately- this is the type I think
might be meddling with the weather (though I shan't go into that
here).

Quite common on the approach route to Manchester Airport over a
region
that is noted for its dry (by UK standards) micro-climate.

The region is a 6 mile triangle of flats once marsh sea-shore
surrounded
by low hills and is given to mists.

On sunny days these trails will last forever it seems.

When an aircraft passes through air that is nearly saturated the
vortices of the air it displaces must be equal to the mass of the
craft.
Complex aerodynamics reduced to simple physics is that the air
supports
the wings and the wings support the plane.

The pressure changes alone must be enough to cause condensation but
as
with the vortices themselves the process is adiabatic or self
contained.
If the weather was going to cloud over anyway then these things would
have formed anyway.

However some bean counters have suggested that the overall picture is
that aircraft take out the high and low points.

What that ammount to is that while overall temperature change is
small
there in less movement in the thermometer.

Or not as the case may be.

At least that is what I gather from the study of the temperatures
over
places like New York after the attack shut down all the airports in
the
USA.

What that study showed was that the diurnal range (difference between
max and min) increased by at least 1 deg C when the contrails were
virtually non-existent*. It wasn't just New York but all over much of
the USA IIRC.

*They picked up the odd contrail from airforce jets and studied how
they spread as well.

http://www.theozonehole.com/airtraffic.htm
http://wired-vig.wired.com/news/tech...,52512,00.html
http://www.climateark.org/articles/r...p?linkid=14028

Edmund