This is an external combustion engine with continuous fuel combustion. The piston expands with air (or helium or hydrogen) as the medium. The expanded gas is cooled in the cold room and circulates continuously. Only a small can make it Rotate quickly to generate powerful power. It has a wide range of applications and is a vivid model showing the basic principles of external combustion engines. People buy it for children's science projects, physics, mechanics learning, etc., to enlighten them to explore more scientific knowledge. The Stirling heat engine is a unique heat engine because its theoretical efficiency is almost equal to the theoretical maximum efficiency, which is called the carnot cycle efficiency. There is a soft rubber pad at the bottom, which is convenient for desktop placement. It can not only be used as teaching aids, decorations, but also DIY. Simple operation, all you have to do is take it out of the box, fill it with 95% and ignite, then, after preheating for a few seconds, let the flywheel rotate, it will rotate quickly and smoothly. It will light up an LED bulb mounted on a small generator. This engine is also a well designed and well made mechanical toy, suitable for people of all ages and all walks of life. For your loved one, this is definitely a wonderful gift, with visual texture and beautiful appearance, sturdy and stable structure and exquisite body, it is simply a work of art.