A Hot Air Stirling Engine is a closed-cycle, external-combustion engine that converts a temperature difference into rotary motion. A light displacer moves air between a hot cap and cold end, while a sealed power piston and 90° phased crank turn pressure changes into work. Runs on a spirit lamp/LPG/electric heater and is perfect to demonstrate thermodynamics, heat transfer, and mechanism design.

Parts Used:

1. Base & Frame – Rigid plate with standoffs and guard.
2. Displacer Cylinder – Glass/SS tube with low-clearance displacer piston and guide.
3. Power Cylinder & Piston – Graphite/aluminum piston with PTFE ring for airtight, low-friction motion.
4. Crankshaft & Flywheel – Ball bearings; 90° phase between displacer and power conrods.
5. Heater Head (Hot Cap) – SS/brass dome over flame or cartridge heater.
6. Cold End & Cooling – Finned aluminum block or water jacket + small fan/pump.
7. Regenerator (optional) – Steel wool/mesh in the passage to recycle heat.
8. Seals & Plumbing – High-temp O-rings, silicone hoses; test port for leak check.
9. Instrumentation (optional) – Thermocouple, tachometer; mini DC generator + LEDs as load.