Another 172RG question- oil system
09-18-2009, 04:49 PM
#1
Gets Weekends Off
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Joined APC: Jul 2008
Position: CFII
Posts: 139
Another 172RG question- oil system
Im training for the complex endrosement, and havent been able to get an answer. The POH seems to be to general.
If you have a oil leak in the prop/governer end of the oil system my understanding is due to centrifugual force and fly weights the prop would naturally go to its high RPM stop.
So is oil going to keep pouring out of your leak in the prop/governer portion of the oil system untill you are out of oil in the entire system and your engine stops, or is their some type of check valve that isolates the rest of the oil system (the engine) in the event of a oil leak in the prop/governer end of the oil system?
wasnt entirely satisfied with my CFI's answer
If you have a oil leak in the prop/governer end of the oil system my understanding is due to centrifugual force and fly weights the prop would naturally go to its high RPM stop.
So is oil going to keep pouring out of your leak in the prop/governer portion of the oil system untill you are out of oil in the entire system and your engine stops, or is their some type of check valve that isolates the rest of the oil system (the engine) in the event of a oil leak in the prop/governer end of the oil system?
wasnt entirely satisfied with my CFI's answer
09-19-2009, 10:01 AM
#2
Prime Minister/Moderator
Joined APC: Jan 2006
Position: Engines Turn Or People Swim
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It's been awhile since I've looked at RG system systems but I do not recall any sort of oil check or shutoff valve. If such a thing existed it would almost have to be manually activated.
In an ASEL oil pressure forces the prop to low RPM/high pitch, so if you lose oil pressure it reverts back to high RPM/low pitch (ME airplanes work the opposite way). But that would probably not happen until you used up all the oil, at which point you would need to pick a spot to land anyway since the engine would fail within minutes.
In an ASEL oil pressure forces the prop to low RPM/high pitch, so if you lose oil pressure it reverts back to high RPM/low pitch (ME airplanes work the opposite way). But that would probably not happen until you used up all the oil, at which point you would need to pick a spot to land anyway since the engine would fail within minutes.
09-19-2009, 10:08 AM
#3
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Joined APC: Feb 2007
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last time i checked...an oil leak is an oil leak...if the side of the gov case is cracked, it will continue to leak. If it was a leak in the cooler, it will still leak. If it is a leak in the pan , it will still leak.ETC....eventually the engine will run out. just my $.02
09-19-2009, 10:20 PM
#4
Gets Weekends Off
Joined APC: May 2009
Position: Another RJ FO
Posts: 1,272
The plane will go to a low pitch high RPM setting with loss of oil pressure. The prop governor will be in an overspeed condition and will try to pump oil into the prop hub to increase blade angle. If the leak is in the prop hub like you said, it should in theory pump all of the oil out of the engine eventually. Getting the RPM down by reducing throttle could buy a pilot some time.
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