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Mach Madness

Short answer: When a jet flies fast through humid air, air pressure and temperature drop over the wings and around the airframe, and water vapor condenses into a visible cloud, often called a vapor cone.

It is common near the speed of sound but can form at subsonic speeds, and it is not itself the shock wave or proof of breaking the sound barrier. Engine contrails are a different effect. The footage shows fighter jets with vapor around the wings, often low over the sea.

VideoWrite-up2 sources
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What should you know about Mach Madness?

Quick facts. Each one stands alone and has a stable ID you can cite.

  1. Low pressure condenses moisture.

    DD-346-F01 · Write-up · Exhibit A (Condensation)

  2. It is called a vapor cone.

    DD-346-F02 · Write-up · Exhibit B (Name)

Video transcript: Mach Madness: Fast Jets Can Wrap Themselves in Sudden White Clouds

The white trails and shrouds seen at the edges of fighter jets, called vapor trails or contrails, form when the jet flies through humid air at high altitudes, near the speed of sound. As it moves, pressure around the wings drops, causing moisture to condense into ice crystals, creating visible trails. When traveling at or beyond the speed of sound, the jet can also produce a Mach cone, a visible shockwave from compressed air as it breaks the sound barrier. NOW YOU KNOW!

Burned-in captions, read frame by frame (see transcript.md) · 23.4s Reel ·

Video coming soonMach Madness · Instagram Reel
Mach Madness: Fast Jets Can Wrap Themselves in Sudden White Clouds Instagram Reel · · 23.4s

The write-up

Fast jets can wrap themselves in sudden white clouds. Low pressure over the wings makes moisture condense.

  1. Exhibit A

    Condensation

    Low pressure condenses moisture.

  2. Exhibit B

    Name

    It is called a vapor cone.

  3. Exhibit C

    Speed

    It forms near the speed of sound.

  4. Exhibit D

    Not sonic boom

    It is not the sound barrier itself.

  5. Exhibit E

    Contrails

    Contrails are a different effect.

Questions people ask about Mach Madness

What is the cloud called?

Condensation.

Source: Write-up · Exhibit A (Condensation) · Wikipedia: Vapor cone

What causes it?

Pressure drop.

Source: Write-up · Exhibit B (Name) · Wikipedia: Vapor cone

Does it prove a jet broke the sound barrier?

Can be subsonic.

Source: Write-up · Exhibit C (Speed) · Wikipedia: Vapor cone

Are contrails the same?

Engine exhaust.

Source: Write-up · Exhibit D (Not sonic boom) · Wikipedia: Vapor cone

What condenses?

From the air.

Source: Write-up · Exhibit E (Contrails) · Wikipedia: Contrail

Test Your Knowledge

All quizzes →

5 questions, all from this case file. Answers are revealed instantly.

  1. What is the cloud called?

    1. Vapor cone
    2. Halo
    3. Aurora
    4. Smoke
    Show the answer

    Answer: A. Vapor cone Condensation. Source: Write-up · Exhibit A (Condensation) · Wikipedia: Vapor cone

  2. What causes it?

    1. Low pressure in humid air
    2. Burning fuel
    3. Paint
    4. Dust
    Show the answer

    Answer: A. Low pressure in humid air Pressure drop. Source: Write-up · Exhibit B (Name) · Wikipedia: Vapor cone

  3. Does it prove a jet broke the sound barrier?

    1. No
    2. Yes
    3. Always
    4. Only at night
    Show the answer

    Answer: A. No Can be subsonic. Source: Write-up · Exhibit C (Speed) · Wikipedia: Vapor cone

  4. Are contrails the same?

    1. No
    2. Yes
    3. Only in winter
    4. Only on jets
    Show the answer

    Answer: A. No Engine exhaust. Source: Write-up · Exhibit D (Not sonic boom) · Wikipedia: Vapor cone

  5. What condenses?

    1. Water vapor
    2. Oil
    3. Nitrogen
    4. Smoke
    Show the answer

    Answer: A. Water vapor From the air. Source: Write-up · Exhibit E (Contrails) · Wikipedia: Contrail

Cite this case file

Easterling, Marcus. "Mach Madness." The Detail Department (DetailEnjoyer), case file DD-346, last updated Oct 16, 2024. https://detailenjoyer.com/case/mach-madness/

Permalink: https://detailenjoyer.com/case/mach-madness/ · Last updated

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