The 'What did you do in your workshop tonight?' thread

[Xpress]

the last thing one wants is all that break-in crud on their airframe.

I think that's a universal feeling!!!!

 

[49dimes]

When it comes to engines I'm TOTALLY Transparent these days. So I agree with both of you fellas

 

[AKNick]

To each his own, your way works for you, mine for me. I did not mention peaking higher than 200° for sake of others that try and do not know enough. I do mine in a controlled environment with tach's, temp gauges, and if needed added airflow by way of an A/C blower but have only needed it once. I have engine's ten years old still running like new, they are "not" DA, some are rather on the cheaper side.
When one builds scale the last thing one wants is all that break-in crud on their airframe. So break-in can easily be done prior to installing in the plane.

Wonder if a guy can slap on a cooling fan... wait a minute it has one! LOL weed eaters, chainsaws... all run on the same principle (stationary air, with a cooling vein fan attached to the hub). I do think breaking them in on the airframe up in the sky is the best method... not the only

 

[acerc]

Wonder if a guy can slap on a cooling fan... wait a minute it has one! LOL weed eaters, chainsaws... all run on the same principle (stationary air, with a cooling vein fan attached to the hub). I do think breaking them in on the airframe up in the sky is the best method... not the only

Our engines have a cooling fan, it's called a prop. Now a cowl enclosed engine on the ground is a whole different story.

 

[AKNick]

Our engines have a cooling fan, it's called a prop. Now a cowl enclosed engine on the ground is a whole different story.

That's what I said ("it has one!") And that aircooled chainsaws and weedeaters have their own built in, it attaches to the crank.
Edit: I see what you are saying though. There is a LOT more airflow with a plane in the air and this beast below which is not stagnant

 

[acerc]

I personally don't think an enclosed engine in the air see's the airflow a naked engine on the ground gets.

 

[AKNick]

Only when baffled correctly Most baffling I've seen is done by directing airflow to the cylinders, not directing all airflow tight around the cylinder(s) which is hard to do. Only then will the stagnant air be neutralized and a mostly uniform cooling be achieved. It's a thing of beauty to get it done right, but for most of us I'd think we just need to get that hot jug cooled down and let most of that air out.

Also I'll add it depends what temp the air already is on the ground. 105F cooling air might not be that effective in comparison to 55F Like it is most of the time here.

Like you say, each to his own!!

 

[49dimes]

Took my foam elsewhere . There's a baffle going on here

 

[Xpress]

Baffling is extremely important, with it you are forcing more cooling air over the cylinder heads in flight than they will ever be exposed to running wide open on the ground, even just the bare engine itself. I have all of my engines baffled, and as shown, chainsaws and leaf blowers, weedeaters even have cooling fans with ducting to force the air over the cylinder heads to keep them cool as a piña colada Another factor to consider is gas engines retain more heat due to more material thickness. My baffling usually has case vents to help vent some air to the case.

 

[AKNick]

Baffling is extremely important, with it you are forcing more cooling air over the cylinder heads in flight than they will ever be exposed to running wide open on the ground, even just the bare engine itself. I have all of my engines baffled, and as shown, chainsaws and leaf blowers, weedeaters even have cooling fans with ducting to force the air over the cylinder heads to keep them cool as a piña colada Another factor to consider is gas engines retain more heat due to more material thickness. My baffling usually has case vents to help vent some air to the case.

I think we all agreethat baffling inside a cowl is important, lots to learn from each other. I’ve picked up the foam air inlet baffling tip somewhere down the line a few years back which helps direct air TO the cylinder inlet and not tightly AROUND the cylinder. Take a looksee at a full scale baffling system. The air is forced to go around tightly against the cylinders usually by sheet aluminum clamped close or held down against the fins with a spring.
You loose a lot of airflow around the cylinder (path of least resistance) then when you have baffling tight up against the cylinder.
Directing the air is great, but not ideal...that air path needs to be tight against the cylinder. Being a full scale aeroplane tech, I’ve played with baffling a lot, and seen some cool stuff over the years (look up plenum baffling) but I have very slim experience on 2cycle gas.
Point being that baffling can be pretty extensive, but there are so many factors to consider and I’d rather like to hear people say they are baffling the inlet air to the cylinder instead of engine baffling unless it’s directing air tight around the actual cyl sides and the rear to the extreme where within the engine box is sealed only letting air get to the cylinder walls/fins. Think compressibility. But like I said, that’s a four stroker with a oil lubrication system. So my knowledge is relevant to that. They need cooling air folks! Lol which goes back to square one ha ha


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