Have any of you ever heard of a Stirling Engine before now? I hadn't it is an external combustion engine. I wonder what became of the technology and why it went no further?

https://www.youtube.com/watch?v=aoKECrXeiV8&t=66s

Wiki sez:
Disadvantages of Stirling engines compared to internal combustion engines include:

Stirling engine designs require heat exchangers for heat input and for heat output, and these must contain the pressure of the working fluid, where the pressure is proportional to the engine power output. In addition, the expansion-side heat exchanger is often at very high temperature, so the materials must resist the corrosive effects of the heat source, and have low creep. Typically these material requirements substantially increase the cost of the engine. The materials and assembly costs for a high-temperature heat exchanger typically accounts for 40% of the total engine cost.[72]
All thermodynamic cycles require large temperature differentials for efficient operation. In an external combustion engine, the heater temperature always equals or exceeds the expansion temperature. This means that the metallurgical requirements for the heater material are very demanding. This is similar to a Gas turbine, but is in contrast to an Otto engine or Diesel engine, where the expansion temperature can far exceed the metallurgical limit of the engine materials, because the input heat source is not conducted through the engine, so engine materials operate closer to the average temperature of the working gas. The Stirling cycle is not actually achievable, the real cycle in Stirling machines is less efficient than the theoretical Stirling cycle, also the efficiency of the Stirling cycle is lower where the ambient temperatures are mild, while it would give its best results in a cool environment, such as northern countries' winters.
Dissipation of waste heat is especially complicated because the coolant temperature is kept as low as possible to maximize thermal efficiency. This increases the size of the radiators, which can make packaging difficult. Along with materials cost, this has been one of the factors limiting the adoption of Stirling engines as automotive prime movers. For other applications such as ship propulsion and stationary microgeneration systems using combined heat and power (CHP) high power density is not required.

Looks like the production of someone who knew how to get some defense funded contracts.

Ha ! Probably right !

Cool find Curtis !

I still thought it interesting to see the outside the box thinking. I saw something on tv over the weekend about some large container ships that will start using Hydrogen power soon.

We had a short section on them in one of my Thermo classes. Invented in 1816. Never widely used.

Yep. Reviewed them in school. Thermo priciples.

I used to work at MIT ~20 years ago and one of the freshman ME labs covered the Stirling engine. Students had to build and run the engine. They even had a contest to see who's ran the longest and fastest. I'm not certain if they currently run the same lab. Here's a graphic of how it works.

http://web.mit.edu/2.670/www/s...005/engine_anim.html