Questions tagged [contrails]

The white lines sometimes seen in the sky trailing an aircraft.

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17
votes
1answer
5k views

Do commercial flights continue with an engine out?

Do commercial flights continue with an engine failure? If you look closely at the attached picture it seems that one of the engines has a much smaller contrail than the other three. This seems to ...
2
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0answers
46 views

Can a weather forecast tell me if airplanes will leave long contrails? [duplicate]

Training 7 ball and 5 club juggling requires me to look up into the sky for durations of up to one minute. Frequently, this is very taxing on my eyes and, frustratingly, requires me to wear sunglasses....
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2answers
2k views

Why don't the contrails show the curvature of the Earth?

When we see contrails in the sky, let's say traveling left/right in your vision, you are seeing across a sky that is easily a couple of hundred miles wide. I mean, we can see one side of space and ...
59
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4answers
11k views

How can a two-engine B787 create three contrails?

Today I noticed overflying aircraft (over Sydney at FL400) which appeared to have three contrails. When I checked Flightradar24 app, I saw that this overflying aircraft is B787. What would be the ...
1
vote
1answer
371 views

Why is this plane flying in such a tight circle?

I was in a car in NYC on 2/18 going from Queens to Manhattan. While going over a bridge I noticed some (what looked to me like) very tight circular contrails in the sky. The plane was still there but ...
9
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3answers
457 views

Where do aerodynamical contrails get their condensation nuclei from, when forming at high altitude?

On this website, it is explained how aerodynamical contrails form: It’s formed by the reduction of pressure in the air as it moves over the wing. When the pressure of a gas falls, then its ...
21
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2answers
4k views

Why are only some aircraft in this formation creating contrails?

The Republic Day celebrations at New Delhi, India had a series of flypasts by the Indian Air Force. What struck me the most was that in a formation with a C-17 in middle and two Su-30MKI flanking it, ...
6
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1answer
555 views

How to read the Appleman chart to predict contrail formation?

I stumbled upon the Appleman-chart, that makes it possible to predict the formation of contrails. How do I use this chart?
3
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1answer
618 views

How does engine exhaust temperature affect contrail formation and why?

There was a german study about the "Influence of propulsion efficiency on contrail formation". In this study, an Airbus A340 and a Boeing 707 flew right next to each other. The two contrail forming ...
11
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1answer
552 views

How do contrails form? [duplicate]

For my pre-scientific work I now need some general information about contrails. I searched for websites that explain the process of contrails being formed in detail but couldn't find any so far. I ...
4
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2answers
485 views

Have contrails ever occurred at low altitudes, such as at takeoff?

Contrails form from the exhaust of jet engines condensing to water-ice. Has this ever happened at low altitudes, especially during or immediately after takeoff?
5
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2answers
578 views

How do contrails compare between piston-powered aircraft and jet aircraft?

Based off this question, I got interested on how contrails compare between jet engines and piston powered engines. Seeing images like these from WWII, I am wondering what the significant differences ...
18
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2answers
3k views

How does contrail formation differ from turbofan to turbojet?

Air forces and intelligence agencies are indeed interested in predicting whether condensation trails (contrails) will be visible or not during aircraft operations. Photo: C-CYOW at Photobucket Among ...
2
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0answers
74 views

Why are some jet trails longer and some shorter? [duplicate]

One can see jet trails behind an airplane. I know that they form because of rapid condensation of Jet exhaust. But I can't figure out why some remain for too long time (hence, longer) while some are ...
28
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4answers
8k views

Do propeller planes give contrails like jets do?

Last weekend, while watching the second world war film "Fury" with a friend, there was a scene near the end with a large set of bombers flying overhead, leaving large contrails. That seemed wrong to ...
28
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6answers
6k views

Do jet contrails impact weather?

Do jet contrails impact weather at the ground?
10
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3answers
2k views

Can an APU exhaust make a contrail in flight?

I saw this picture in a local newspaper. My thoughts were, silly artists, that's the APU exhaust, it won't ever produce a trail like that during takeoff (or ever). Of course, the picture is clearly ...
15
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3answers
2k views

Why are contrails not visible from the cabin?

If you observe a plane flying whilst on the ground, plenty of times you will see contrails: Why are they not visible from the plane itself when sitting in the most rear part of the cabin even by ...
12
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3answers
6k views

What is the mechanism by which condensation forms above wings?

The planes landing at Sydney Airport have what looks to be sheets of steam pouring off the wings. Larger planes have multiple contrails while smaller regional planes only have these sheets. This is ...
39
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4answers
71k views

Why does an aircraft leave a white smoke trail?

Why does an aircraft leave a white smoke trail?
31
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3answers
5k views

Do stealth airplanes need to limit contrail generation?

Stealth aircraft have low visibility on radar. I assume that they strive to achieve low visibility optically as well, e.g. spend some effort to not stand out too much visually from the surroundings. ...
20
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1answer
2k views

Why are some contrails longer than others?

I've often noticed that planes flying on more or less the same track, headed in the same direction leaves different contrails. By different I mean how long they stay visible and the length of them. ...
9
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2answers
2k views

If jet engines did leave chemtrails, wouldn't the chemicals cause adverse reactions in the engines?

Please note, this question does not call into question whether or not the conspiracy theory is true or untrue, but the feasibility of certain chemicals being used as fuel additives in order to make ...
19
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2answers
3k views

How long does it take for a contrail to hit the ground? [closed]

I'm not even sure if they end up falling to earth, or if they accumulate and form/join other clouds or whatnot, which is part of the reason I'm asking this question. In contrails, heavier particles ...