Does Oil Viscosity Impact Low Temperature Stirling Engine Performance?

[MacLaddy]

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.

 

[Cyrus]

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.

 

[MacLaddy]

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.

 

[dr dodge]

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