What you needed was a black metal ring fit on the tube where the sunlight hits to spread the heat and avoid the crack. The crack occurred because sunlight heated some thin filament of metal to a very high temperature causing thermal stress on the glass tube. To be honest I find people needlessly use glass tubes for these engines, all that you need is to know exactly the length of the steel wool section inside the tube, and adjust the flame using the measurements and use a metal tube instead.
@AlBarathur Yes, I think glass is a very bad idea when it comes to using the sun and a magnifying glass. A larger fresnel lens would probably even melt the glass. I'm going to start using stainless steel some time in the future.
@BuildSomethingUseful Keep in mind though that metal conduct heat differently than glass. If the whole pipe is metal, you might need some serous heat dissipation, or maybe not, it is hard to tell
@AlBarathur I hear you. I would use a very thin walled stainless steel but the thermal conductivity of stainless steel is right between glass and aluminum according to a quick google search.
excelente.
RMSSSANTOS 2 months ago
@RMSSSANTOS Gracias.
BuildSomethingUseful 1 month ago
What you needed was a black metal ring fit on the tube where the sunlight hits to spread the heat and avoid the crack. The crack occurred because sunlight heated some thin filament of metal to a very high temperature causing thermal stress on the glass tube. To be honest I find people needlessly use glass tubes for these engines, all that you need is to know exactly the length of the steel wool section inside the tube, and adjust the flame using the measurements and use a metal tube instead.
AlBarathur 2 months ago
@AlBarathur Yes, I think glass is a very bad idea when it comes to using the sun and a magnifying glass. A larger fresnel lens would probably even melt the glass. I'm going to start using stainless steel some time in the future.
BuildSomethingUseful 1 month ago
@BuildSomethingUseful Keep in mind though that metal conduct heat differently than glass. If the whole pipe is metal, you might need some serous heat dissipation, or maybe not, it is hard to tell
AlBarathur 1 month ago
@AlBarathur I hear you. I would use a very thin walled stainless steel but the thermal conductivity of stainless steel is right between glass and aluminum according to a quick google search.
BuildSomethingUseful 1 month ago
Great Video!
moabseeker 3 months ago
@moabseeker I'm glad you like it, thanks for commenting.
BuildSomethingUseful 1 month ago
nice revs there
theCROfna 8 months ago
Robert Stirling only invented the regenerator concept which increases efficiency.
So without a regenerator, it is just a heat engine.
Very nice and simple one though.
johngagne1 8 months ago
It looks like you also got the steel wool a lot closer to the support column than I do. Maybe I should try adding more in.
adfgfds 9 months ago
Thats the exact same kind of candle I was using.
adfgfds 9 months ago
Comment removed
adfgfds 11 months ago