# Mach Madness (DD-346)

> 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.

- Department: Military (also Tech)
- First published: 2024-10-16
- Last updated: 2024-10-16
- Permalink: https://detailenjoyer.com/case/mach-madness/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## Quick facts

- **DD-346-F01**: Low pressure condenses moisture. _(Write-up · Exhibit A (Condensation))_
- **DD-346-F02**: It is called a vapor cone. _(Write-up · Exhibit B (Name))_

## Write-up

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

1. **Condensation**: Low pressure condenses moisture.
2. **Name**: It is called a vapor cone.
3. **Speed**: It forms near the speed of sound.
4. **Not sonic boom**: It is not the sound barrier itself.
5. **Contrails**: Contrails are a different effect.

## Related case files

- [Clouds From the Ground (DD-388)](https://detailenjoyer.com/case/clouds-from-the-ground/): I linked more on condensation clouds

## Reel vs. record

- **Note**: The Reel calls the effect contrails and links it to high altitude and the sound barrier; wing vapor clouds are condensation in humid air, often seen at low altitude, and can form below the speed of sound.

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

- Duration: 23.4 s · Published: 2024-10-16
- File: https://detailenjoyer.com/assets/videos/DBNbPcHpzrA.mp4

### Transcript

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!

## Questions & answers

**Q: What is the cloud called?**  
A: Condensation. _(Source: Write-up · Exhibit A (Condensation) · Wikipedia: Vapor cone)_

**Q: What causes it?**  
A: Pressure drop. _(Source: Write-up · Exhibit B (Name) · Wikipedia: Vapor cone)_

**Q: Does it prove a jet broke the sound barrier?**  
A: Can be subsonic. _(Source: Write-up · Exhibit C (Speed) · Wikipedia: Vapor cone)_

**Q: Are contrails the same?**  
A: Engine exhaust. _(Source: Write-up · Exhibit D (Not sonic boom) · Wikipedia: Vapor cone)_

**Q: What condenses?**  
A: From the air. _(Source: Write-up · Exhibit E (Contrails) · Wikipedia: Contrail)_

## Sources

- [Wikipedia: Vapor cone](https://en.wikipedia.org/wiki/Vapor_cone)
- [Wikipedia: Contrail](https://en.wikipedia.org/wiki/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/