Contrails

"Jeffrey Voight" wrote in message
...

I'm curious about something I frequently see. When I look up and see
contrails from airplanes, I often see more than one headed in the same
direction, but separated by some distance. I figure this is a result of
the trailing aircraft not wanting to fly along in the contrail left by
the lead aircraft and/or the wind pushing the contrail to the side prior
to the trailing aircraft. What I don't get is why I see them bend at or
about the same location. Is this the result of the wind changing
direction at this location? Perhaps the pilots are flying VOR to VOR
and that bend is where the local VOR is?


That is most likely.



I would have thought that most
flights at altitudes that produce contrails would be on GPS plans, so
I've discounted this theory a bit.


In heavy traffic areas aircraft are still tied to preferential routes along
airways regardless how they're equipped.

Perhaps the pilots are flying VOR to VOR
and that bend is where the local VOR is?

Iowa City was on the original transcontinental air mail route. When they
switched from light beacons to radio beacons, Iowa City received a VOR.

(In the 1920s and 30s, Iowa City has a 500,000,000 candlepower beacon!
That's half a BILLION candlepower -- it was reported in the newspapers that
area farmers were able to work at night, by the light of the beacon!)

These routes evolved into the airways airlines (and many IFR pilots) still
use today.

On a clear day you can see dozens of airliners overhead, changing course at
the VOR just south of town. 99% of the population has no idea why.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

On 2003-12-06 12:32:51 -0800, Jeffrey Voight said:

I would have thought that most
flights at altitudes that produce contrails would be on GPS plans....

Two things:

1. There are lots of big airplanes flying around that still have nothing more than
the good old VOR & DME.

2. GPS doesn't always mean direct.

--
Larry Fransson
Seattle, WA

What I don't get is why I see them bend at or
about the same location

I suspect it's winds aloft.

all the best -- Dan Ford
email:

see the Warbird's Forum at www.warbirdforum.com
and the Piper Cub Forum at www.pipercubforum.com

No, no, Jay. You know damned good and well those are chemtrails dusting us with
evil powders.

Jim


"Jay Honeck"
shared these priceless pearls of wisdom:

-On a clear day you can see dozens of airliners overhead, changing course at
-the VOR just south of town. 99% of the population has no idea why.

Jim Weir (A&P/IA, CFI, & other good alphabet soup)
VP Eng RST Pres. Cyberchapter EAA Tech. Counselor
http://www.rst-engr.com

"Jay Honeck" wrote in message
news:VJrAb.441007$HS4.3464811@attbi_s01...

Iowa City was on the original transcontinental air mail route. When they
switched from light beacons to radio beacons, Iowa City received a VOR.


Well, actually, they didn't. When radio navigation was introduced in the
late twenties it was in the form of the four course A-N radio range, VOR
didn't come along until the late forties.



(In the 1920s and 30s, Iowa City has a 500,000,000 candlepower beacon!
That's half a BILLION candlepower -- it was reported in the newspapers
that
area farmers were able to work at night, by the light of the beacon!)

These routes evolved into the airways airlines (and many IFR pilots) still
use today.


I have a 1939 Des Moines sectional chart. It shows the airway passing just
south of the Iowa City Airport. The airway is defined by A-N ranges at
Moline and Des Moines. There's a rotating beacon on the field at Iowa City,
and rotating beacons with course lights on the airway southeast and
southwest of Iowa City.

The 1945 sectional shows the airway now designated Green 3 and an NDB at
Iowa City.

The 1948 sectional shows some extensions to controlled airspace around the
Iowa City airport, no doubt to contain an instrument approach. The only
change to the visual or radio navaids is the addition of a visual ground
sign about three miles northwest of Riverside.

The 1953 sectional shows significant changes. The airway light beacons,
visual ground sign, and the NDB are gone. The Iowa City VOR is located
where the visual ground sign was. V6 and V8 run from the Des Moines VOR
through Iowa City VOR to the Moline VOR. The Des Moines VOR is located
about three miles south-southwest of the Des Moines Range, the Moline VOR is
located about four miles northeast of Cordova, Illinois.

The 1960 sectional shows a few more airways defined by the IOW VOR.

The 1964 sectional no longer shows the A-N ranges.

Jim Weir opined

No, no, Jay. You know damned good and well those are chemtrails dusting us
with evil powders.

Damn. I was just about to post the same explaination.

-ash
for assistance dial MYCROFTXXX

I live "almost" under a convergence of airways. Most any clear fall
evening, you can count the contrails into the double digits. And most all
of them bend in the same place....following an airway one way or the other.
By dark, you can generally make out where the airways are and aren't.

Jeff

"Jeffrey Voight" wrote in message
...
I'm curious about something I frequently see. When I look up and see
contrails from airplanes, I often see more than one headed in the same
direction, but separated by some distance. I figure this is a result of
the trailing aircraft not wanting to fly along in the contrail left by
the lead aircraft and/or the wind pushing the contrail to the side prior
to the trailing aircraft. What I don't get is why I see them bend at or
about the same location. Is this the result of the wind changing
direction at this location? Perhaps the pilots are flying VOR to VOR
and that bend is where the local VOR is? I would have thought that most
flights at altitudes that produce contrails would be on GPS plans, so
I've discounted this theory a bit. If it's the result of the wind
changing, wouldn't the wind shear destroy the contrail at that bend?

I don't get it.

Jeff...

"99% of the population has no idea why."
Jay, I submit this is generally true.
;^)
H.

"Jay Honeck" wrote in message
news:VJrAb.441007$HS4.3464811@attbi_s01...
Perhaps the pilots are flying VOR to VOR
and that bend is where the local VOR is?

Iowa City was on the original transcontinental air mail route. When they
switched from light beacons to radio beacons, Iowa City received a VOR.

(In the 1920s and 30s, Iowa City has a 500,000,000 candlepower beacon!
That's half a BILLION candlepower -- it was reported in the newspapers
that
area farmers were able to work at night, by the light of the beacon!)

These routes evolved into the airways airlines (and many IFR pilots) still
use today.

On a clear day you can see dozens of airliners overhead, changing course
at
the VOR just south of town. 99% of the population has no idea why.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"Steven P. McNicoll" wrote:

I have a 1939 Des Moines sectional chart........

Do you collect old sectionals, or is there a library of these things someplace?

George Patterson
Some people think they hear a call to the priesthood when what they really
hear is a tiny voice whispering "It's indoor work with no heavy lifting".