Engineering News Blog

Engineering News

Latest news of interest to engineers. Sourced from GlobalSpec's Engineering News
Previous in Blog: Huge Helicopter Bicycle Lifts Off Powered by One Person   Next in Blog: US East Coast Set for Severe Sea Level Rise
Close

Comments Format:






Change Mode
Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







Add Vote
3 comments
Rate Comments: Nested

Vapor Trails and Cones

Posted June 24, 2012 12:57 PM

From The Presurfer:

These pictures of plumes of air billowing from the back ends of aircraft may seem like a cause for concern. But these images actually show spinning vapor trails created by cold air circulating around the wing.

Read the whole article

Reply

Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Good Answers:

These comments received enough positive votes to make them "good answers".
2
Tornado
Guru
Technical Fields - Technical Writing - New Member Engineering Fields - Piping Design Engineering - New Member

Join Date: May 2009
Location: Richland, WA, USA
Posts: 21017
Good Answers: 795
#1

Re: Vapor Trails and Cones

06/24/2012 9:41 PM

The pix are beautiful, but the explanations aren't quite correct.

1. The helical (not conical) contrails come from vortices at the propeller tips.

2. The air may already be cool, but the reduction in pressure causes further cooling, and hence condensation of water vapor into a visible fog of droplets spiraling off the wing (or prop) tips.

__________________
 In vino veritas; in cervisia carmen; in aqua E. coli.
Reply Good Answer (Score 2)
No more Good Answers.
truth is not a compromise
Guru

Join Date: Apr 2011
Posts: 8006
Good Answers: 286
#2
In reply to #1

Re: Vapor Trails and Cones

06/25/2012 3:36 AM

I agree on both points:

The pictures are beautiful and definitely worth viewing.

The explanations are lacking and much improved with Tornado's corrections.

I would add that the water vapor resulting from fuel combustion has a significant effect on the visibility and longevity of contrails.

Also, if you need a good laugh, a flock of chem-trailers have marked the comment section below the linked article with their typical zany flavor of pseudologic.

__________________
 Eternal vigilance is the price of knowledge. - George Santayana
Reply
CaptMoosie
Guru
Hobbies - DIY Welding - New Member Hobbies - Target Shooting - New Member Engineering Fields - Civil Engineering - New Member United States - Member - New Member

Join Date: May 2009
Location: Red Hook, New York (Mid-Hudson River Valley)
Posts: 4362
Good Answers: 179
#3

Re: Vapor Trails and Cones

06/25/2012 7:27 AM

I like the pics of the US Navy F-18F Super Hornet the best, followed by the F-22A Lightning II (ie, the Raptor)....

Incredible pics all

__________________
 "Veni, Vidi, Vici"; hendiatris attributed to Gaius Julius Caesar, 47 B.C.
Reply
Reply to Blog Entry
Have a Different Question?
3 comments

Good Answers:

These comments received enough positive votes to make them "good answers".
Copy to Clipboard

Users who posted comments:

CaptMoosie (1); Tornado (1); truth is not a compromise (1)

Previous in Blog: Huge Helicopter Bicycle Lifts Off Powered by One Person   Next in Blog: US East Coast Set for Severe Sea Level Rise

Advertisement

Got Something to Say?
Ask a Question
Start a Discussion

Search this Section
General Discussion:
Go

Search this Blog
Engineering News:
Go

Recent Blog Entries

CR4 Sections
Aerospace
BioMech & BioMed
Chemical & Material Science
Civil Engineering
Communications & Electronics
Education and Engineering Careers
Electrical Engineering
General Discussion
Instrumentation
Manufacturing
Mechanical Engineering
New Technologies & Research
Software & Programming
Sustainable Engineering
Transportation

Site Directories
Forum Directory
Blog Directory
User Group Directory
RSS Feeds

CR4 Rules of Conduct
CR4 FAQ
Site Glossary

Who's Online (42 right now)
Show Members
Advertisement