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Old 09-05-2011, 09:11 AM
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DarZeelon
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Default RE: Tapered-Bore Engine Break-in - Upgraded


ORIGINAL: Recycled Flyer


ORIGINAL: DarZeelon

Getting rid of the heat is apparently not the reason plane engines need more oil.
After all, gas guys easily get away with just 2-3%, or even less.
Thats a strange thing to say since gasoline has no lubricating properties as such, its more that gas engines tend to be larger in size and so can physically support needle rollers on the big and small ends thereby eliminating the most critical oil dependant sliding part of the engine. And the finning on these engines seems to be proportionally much larger in area than its smaller glow cousins.
Chris,


Some small specialty engines had needle bearing con-rods too.

The one I know about is the discontinued MVVS #3070 GRRT/GRFT (differing in either front, or rear induction).




The methanol in the fuel cools through evaporation, mostly when it is in the combustion chamber.
In the crankcase it cools through sheer mass. Methanol is used at about 2.4 times the rate of gasoline/petrol.

This is one of the reasons our glow engines have (and need) smaller cooling fins.


Your info on the lapped engines makes sense.