Llewtrah381
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Llewtrah
I’ve been searching the interweb a bit to try and learn more about how one would locate an induction leak. This video keeps popping up and seems to be the only/best one I can find on the topic and is referenced by several other aviation sites:
https://youtu.be/CfG4QGv-r64
While talking through the procedure, around 2:15 they talk about starting the prop at top dead center for the cylinder being “charged” (they say it’s #1 but it sure looks like #3 or maybe #4 to me, unless Continentals are numbered very strangely). They then show him rotating the prop forward a bit to “charge” the cylinder and then going back, past the starting point, when you can hear it “chuff” and put air into the induction system.
That all makes sense BUT shouldn’t that be happening at BOTTOM dead center, between the intake and compression strokes? Seems like if it’s actually at TDC on the compression stroke he’d be rolling back and forth between the compression and power strokes - with no valves opening for a good while in either direction.
I haven’t seen anyone on other sites comment on this but it seems incorrect to me. Am I missing something?
The rest of the procedure seems pretty straightforward. I imagine it can be done with any cylinder and you don’t need to repeat it on any others: doing it in any one would charge the whole induction system for testing. I suppose, debatably, doing it on a cylinder from both sides would increase the “yield” by ensuring a leak on the opposite side gets a good amount of air flow but I’m not sure.
https://youtu.be/CfG4QGv-r64
While talking through the procedure, around 2:15 they talk about starting the prop at top dead center for the cylinder being “charged” (they say it’s #1 but it sure looks like #3 or maybe #4 to me, unless Continentals are numbered very strangely). They then show him rotating the prop forward a bit to “charge” the cylinder and then going back, past the starting point, when you can hear it “chuff” and put air into the induction system.
That all makes sense BUT shouldn’t that be happening at BOTTOM dead center, between the intake and compression strokes? Seems like if it’s actually at TDC on the compression stroke he’d be rolling back and forth between the compression and power strokes - with no valves opening for a good while in either direction.
I haven’t seen anyone on other sites comment on this but it seems incorrect to me. Am I missing something?
The rest of the procedure seems pretty straightforward. I imagine it can be done with any cylinder and you don’t need to repeat it on any others: doing it in any one would charge the whole induction system for testing. I suppose, debatably, doing it on a cylinder from both sides would increase the “yield” by ensuring a leak on the opposite side gets a good amount of air flow but I’m not sure.