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  #1  
Old 05-08-2009, 05:40 PM
gbumga gbumga is offline
 
Join Date: Feb 2006
Posts: 71
Default Aerobatic breather fitting inside engine ?

Hi, I could be way of base but I've never heard anyone on VAF mention anything on the inside of the engine to help min. oil loss out the breather tube during aerobatics. I know on the continental engine for aerobatics there is a 90 degree fitting on the inside so when the oil migrates to the side of the case very little [or less] gets out of the engine. if there is no 90 degree fitting all the oil that slides by the opening goes out, if you have a 90 degree fitting most goes right pass. Doesn't Lycoming have the same option for a fitting at that opening. And if not couldn't you tread that opening and put one in anyways? just want to throw this out and see what you guys with Lycoming know how, know or think about this. Gene
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Gene Bumgarner RV-7 Emp./wings
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  #2  
Old 05-08-2009, 06:10 PM
asav8tor asav8tor is offline
 
Join Date: Oct 2006
Location: Seattle, wa
Posts: 679
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If you are doing positive G aerobatics the oil doesn't know it's upside down. If you are doing neg G aerobatics and oil is dumping out the breather you are running the risk of unporting the suction screen. An effort to minimized oil loss out the breather (by adding something as you describe) means you are moving closer to aero that could unport the suction screen. Oil out the breather is messy. Unporting the suction screen means throwing a rod and busting a big hole in the crankcase. Use the oil out the breather to tell you "watch the neg or zero Gs"..... Fly your aero more carefully and you will keep the belly clean and avoid oil pressure interruptions.

If you want to rack around and push neg G, put on the inverted system.

Be one with the engine. It talks to you.

Last edited by asav8tor : 05-08-2009 at 06:13 PM.
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  #3  
Old 05-09-2009, 08:04 AM
rv7charlie rv7charlie is offline
 
Join Date: May 2006
Location: Pocahontas MS
Posts: 3,884
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I've never seen the inside of a cont crankcase, but I think gbumga has a valid point. You don't have to do actual negative G to cause significant oil loss; I see much higher oil consumption doing loops, rolls, cuban8s, etc than when flying straight & level.

Maybe the equivalent of an auto engine's windage tray?

Charlie
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