Hot-air engines explained: a free interactive guide to Stirling engines

Hot-air engines explained

From confined gas to measured power

Why does a Stirling engine run — and what does it take to turn a small working model into a useful generator?

This free interactive guide follows the journey from enclosed air and heat transfer to engine layouts, losses, materials and measured power. Explore the moving diagrams, try the calculators and open the background notes whenever you want to go deeper. The main route focuses on mechanically driven hot-air engines.

20 chapters + references · English · No sign-up required
On a small screen, rotate your phone for larger diagrams.

Explore the contents

1. What happens to enclosed air?
2. From a single expansion to a complete cycle
3. What does the displacer do?
4. The regenerator stores heat between flow reversals
5. Motion timing and phase angle
6. Alpha, beta, gamma
7. What makes an engine start, and why does it stop?
8. Efficiency, heat flow and power
9. From heat source to shaft
10. Size, pressure, speed
11. Working gases
12. It turns – but how much can it deliver?
13. What does a kilowatt mean in practice?
14. How does enough heat reach the working gas?
15. What makes a usable regenerator?
16. How can the hot and cold sides be separated?
17. What prevents easy, durable operation?
18. How do we choose an engine for a task?
19. From first design to reliable measurement
20. Built engines — what do real examples show?
21. References and further reading