Oil Viscosity & LT Stirling

In summary, this website says that you should never oil the working piston in the cylinder of a Stirling engine, but this is a toy and the English translation did not change the main text.
  • #1
MacLaddy
Gold Member
291
11
I have been doing a bit of research on building a low temperature Stirling engine, and I came across this website,

http://heetgasmodelbouw.ridders.nu/Webpaginas/pagina_koffiekop_jan/koffiejan_frameset.htm

The design on this website looks nice, and I would like to give it a go (after I build a simpler model), but I have my doubts about the following statement within the instructions.

Never oil the working piston in the cylinder! Even very thin oil is more or less viscous and increases the friction. Mind that the power of this type of Stirling models is very low so little friction can be fatal.

Any thoughts on this? I understand oil could be a bit viscous, but it wouldn't seem to be so dramatic that you would want to run this engine dry.

*EDIT* Be sure to hit the "English" button at the very top of the webpage.
 
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  • #2
It looks cute, but the RPM is unimpressive, to say the least, as those props want to turn around 5-6 thousand rpm to generate any appreciable thrust.
 
  • #3
Cyrus said:
It looks cute, but the RPM is unimpressive, to say the least, as those props want to turn around 5-6 thousand rpm to generate any appreciable thrust.

Well, I don't believe it's designed to be anything more than a toy. I personally want to build it just so I can get a better understand of the inner workings of a Stirling. Plus, it runs on a coffee cup. I mean how cool is that?

I will be starting to build this one in a day or so,

http://www.physics.sfasu.edu/astro/courses/egr112/StirlingEngine/stirling.html

but I am still curious about the "To oil, or not to oil" situation. This one calls for a thin coat of oil, whereas the other one says not to use it.
 
Last edited by a moderator:
  • #4
oil can have a significant effect on mechanical performance. even a very light oil will slowly thicken over time, grab dust from the air, and change with humidity. Thats why most dial gauges, watches, and other precision mechanicals use no oil. In some of our precision pneumatic equipment, just the residual oil from a finger will prevent its function.
nice links, but the english conversion didn't change the main text
(I was bummed...looks interesting...must learn dutch now...lol)

dr
 

What is oil viscosity?

Oil viscosity refers to the measurement of a fluid's resistance to flow. It is a measure of how thick or thin the oil is, and it is influenced by factors such as temperature, pressure, and the composition of the oil.

How does oil viscosity affect the performance of an LT Stirling engine?

The viscosity of the oil used in an LT Stirling engine is important because it affects the efficiency and power output of the engine. If the oil is too thick, it can create more friction and resistance, resulting in lower efficiency and performance. On the other hand, if the oil is too thin, it may not provide enough lubrication, leading to increased wear and tear on the engine.

What is the ideal oil viscosity for an LT Stirling engine?

The ideal oil viscosity for an LT Stirling engine depends on several factors, including the design and specifications of the engine, the temperature at which it operates, and the type of oil used. It is important to consult the manufacturer's recommendations for the specific engine model to determine the optimal viscosity for maximum performance and longevity.

How does oil viscosity change with temperature in an LT Stirling engine?

The viscosity of oil is highly dependent on temperature. As temperature increases, the oil becomes thinner and flows more easily. This can be beneficial for an LT Stirling engine, as it can improve performance and reduce friction. However, if the temperature gets too high, the oil may become too thin and cause issues such as reduced lubrication and increased wear on engine components.

Can changing the oil viscosity in an LT Stirling engine improve its performance?

Changing the oil viscosity in an LT Stirling engine can potentially improve its performance, but it is important to make sure that the new viscosity is within the recommended range for the engine and its operating conditions. A change in viscosity can affect the engine's efficiency, power output, and longevity, so it is crucial to consult the manufacturer's recommendations and make any changes carefully and with caution.

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