RCU Forums - View Single Post - Importance of engine break-in ?

05-08-2009 | 09:57 PM

#29

DarZeelon

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From: Rosh-HaAyin, ISRAEL

RE: Importance of engine break-in ?

Quote:

ORIGINAL: Cyberwolf

Any engine will cool better in the air, And again if your engine is set where its supposed to be you won't have a lean run in the air.

CW,

This is not necessarily so. Using a smaller diameter prop during static break-in will reduce the load imposed upon the engine...

...In fact; during static break-in, all the prop needs to do is to provide flywheel effect, so the engine will go on spinning and to provide just enough air-flow, so the engine's heat would be kept at bay.
If break-in is done in flight, the prop will also be required to produce effective thrust, that would keep the plane flying along...

I've just convinced my self. That sentence is necessarily incorrect and the safest and best way to perform a low-load break-in, is on the ground.

But... a very low-load is not always what you want during break-in...
For a tapered-bore engine, you need the engine at its normal working temperature...

For a ringed engine, you need to keep it cold only for an initial tank, or two. This, to remove the larger 'ridges and valleys'...
Afterward you need 75-85% load, to properly bed the ring(s) and the sleeve together and to prevent any onset of glazing on the sleeve wall...

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