# Pulse Jar (DD-586)

> A pulse jet engine burns a fuel-air mixture in rapid, repeated pulses. Jar versions improvise the idea: a small opening lets air in, a flammable vapor such as alcohol is added, and ignition makes the burning gas build pressure and rush out of the opening, often pulsing. The Reel itself calls this a highly dangerous experiment. The footage, credited to eurekahnb, shows a burning jar demonstration.

- Department: Science (also Tech)
- First published: 2025-06-01
- Last updated: 2025-06-01
- Permalink: https://detailenjoyer.com/case/pulse-jar/
- Author: Marcus Easterling (DetailEnjoyer), The Detail Department

## Quick facts

- **DD-586-F01**: Pulse jet. _(Write-up · Exhibit A (Engine))_
- **DD-586-F02**: Rapid pulses. _(Write-up · Exhibit B (Cycle))_

## Write-up

A jar with a small hole can mimic a pulse jet engine. Fuel vapor burns in rapid pulses.

1. **Engine**: Pulse jet.
2. **Cycle**: Rapid pulses.
3. **Jar setup**: Small opening.
4. **Fuel**: Alcohol vapor, per the Reel.
5. **Risk**: Highly dangerous, per the Reel.

## Reel vs. record

- **Note**: None needed.

## Video: Pulse Jar: A Jar With a Small Hole Can Mimic a Pulse Jet Engine

- Duration: 24.7 s · Published: 2025-06-01
- File: https://detailenjoyer.com/assets/videos/DKX4qHzyWnm.mp4

### Transcript

Did you know, creating pulse jets in jars is a highly dangerous and improvised experiment that attempts to replicate the basic principles of a pulse jet engine in a confined space. A pulse jet operates by combusting a fuel air mixture in rapid pulses. In a jar setup, a small hole is typically made for air flow, and a flammable vapor like alcohol or gas is introduced inside. When ignited, the rapid combustion causes pressure to build up and expel hot gases out of the jar. NOW YOU KNOW!

## Questions & answers

**Q: Mimics?**  
A: Pulses. _(Source: Write-up · Exhibit A (Engine) · Wikipedia: Pulsejet)_

**Q: Combustion?**  
A: Cycle. _(Source: Write-up · Exhibit B (Cycle) · Wikipedia: Pulsejet)_

**Q: Fuel example?**  
A: Vapor. _(Source: Write-up · Exhibit C (Jar setup) · Wikipedia: Pulsejet)_

**Q: Air enters via?**  
A: Opening. _(Source: Write-up · Exhibit D (Fuel) · Wikipedia: Pulsejet)_

**Q: Reel's warning?**  
A: Risk. _(Source: Write-up · Exhibit E (Risk) · Wikipedia: Pulsejet)_

## Sources

- [Wikipedia: Pulsejet](https://en.wikipedia.org/wiki/Pulsejet)

## Cite this case file

Easterling, Marcus. "Pulse Jar." The Detail Department (DetailEnjoyer), case file DD-586, last updated Jun 1, 2025. https://detailenjoyer.com/case/pulse-jar/