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#1
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Prop Feathers and Engine Shuts down after landing????????
Today I was flying my Twin Comanche PA30 everything was great until after
landing. Once I had the wheels on the ground I pulled the power back to idle, about three seconds or so after I pulled the power back the prop feathered and the engine shut down. I let the engine cool down for about 30 min then started the engine right up. Everything was running great. So I took off and flew around for a while then came back to land, this time after I landed I put the power back up to 1500 rpm, the oil temp was right below redline the oil was at 50psi then the prop feathered and the engine shut down again. This also happened to me yesterday. Every time I land the prop feathers and the engine shuts down . Everythings always great until after landing. I only have 40 hours on the engine. Could anyone please help me out? Has this ever happened to anyone before? Does anyone have any ideas on what it could be thanks for everyone’s help. |
#2
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This is only a guess but may make some sense. Some CS props will go full
pitch if oil pressure is lost, others will to to minimum pitch with no oil pressure. You said that the oil temperature was high. (an indication of low oil level). Also how is the oil pressure just before it shuts down? Being at idle already, full pitch could make enough drag to stall the engine. OTOH, if the engine stalled first, the lack of oil pressure would cause the prop to feather too. Make sure the oil is the right viscosity too. In planes with oil inversion systems, it's important that you have the type of prop that goes to full pitch because the pressure drop during the transition to inverted would cause an engine overspeed if it was the type that went to minimum pitch. Not that yours has an inversion system, but it's nice to know which prop you have. Let me know how you make out, I will be reading the other replies too but am curious to answer to your problem. Wayne "AIR ADVENTURE82" wrote in message ... Today I was flying my Twin Comanche PA30 everything was great until after landing. Once I had the wheels on the ground I pulled the power back to idle, about three seconds or so after I pulled the power back the prop feathered and the engine shut down. I let the engine cool down for about 30 min then started the engine right up. Everything was running great. So I took off and flew around for a while then came back to land, this time after I landed I put the power back up to 1500 rpm, the oil temp was right below redline the oil was at 50psi then the prop feathered and the engine shut down again. This also happened to me yesterday. Every time I land the prop feathers and the engine shuts down . Everythings always great until after landing. I only have 40 hours on the engine. Could anyone please help me out? Has this ever happened to anyone before? Does anyone have any ideas on what it could be thanks for everyone's help. |
#3
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Since the original poster indicated they were flying a twin, they most
definitely have a prop which feathers if oil pressure is lost, otherwise single engine handling could become even more exciting than usual. Of course, someone somewhere doubtless knows of a counter example. For a single, the reverse is usually true: the prop goes to fine pitch if you lose oil pressure. That being said, high oil temperature and low oil pressure are definitely clues. What's curious is that you don't see this behavior just idling. If low oil levels were the culprit, I'd expect the same thing to happen after a ground runup. I think it's time to talk to an A&P. mark "Wayne" wrote in message ... This is only a guess but may make some sense. Some CS props will go full pitch if oil pressure is lost, others will to to minimum pitch with no oil pressure. You said that the oil temperature was high. (an indication of low oil level). Also how is the oil pressure just before it shuts down? Being at idle already, full pitch could make enough drag to stall the engine. OTOH, if the engine stalled first, the lack of oil pressure would cause the prop to feather too. Make sure the oil is the right viscosity too. In planes with oil inversion systems, it's important that you have the type of prop that goes to full pitch because the pressure drop during the transition to inverted would cause an engine overspeed if it was the type that went to minimum pitch. Not that yours has an inversion system, but it's nice to know which prop you have. Let me know how you make out, I will be reading the other replies too but am curious to answer to your problem. Wayne "AIR ADVENTURE82" wrote in message ... Today I was flying my Twin Comanche PA30 everything was great until after landing. Once I had the wheels on the ground I pulled the power back to idle, about three seconds or so after I pulled the power back the prop feathered and the engine shut down. I let the engine cool down for about 30 min then started the engine right up. Everything was running great. So I took off and flew around for a while then came back to land, this time after I landed I put the power back up to 1500 rpm, the oil temp was right below redline the oil was at 50psi then the prop feathered and the engine shut down again. This also happened to me yesterday. Every time I land the prop feathers and the engine shuts down . Everythings always great until after landing. I only have 40 hours on the engine. Could anyone please help me out? Has this ever happened to anyone before? Does anyone have any ideas on what it could be thanks for everyone's help. |
#4
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"AIR ADVENTURE82" wrote in message ... Today I was flying my Twin Comanche PA30 everything was great until after landing. What oil are you using? Warm temperatures and a too light weight oil can cause low pressures. |
#5
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"Dennis O'Connor" wrote in message ... Either the prop governor, or the piston in the hub are going to hell in a handbasket... The engine 'stalls' when the prop goes into feather - I doubt that there is an engine problem... Sending the governor out for overhual immediately, would be my inclination... Actually, it may just be a bad idle mixture setting. My engine when hot used to stall at idle (frequently rolling out with the throttle at idle). I didn't have a twin, but I can imagine that the prop would feather during such a sequence in a twin. |
#6
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Shouldn't the prop feather when you lose oil pressure (on a twin)? Sounds
like the prop is behaving normally to me. More likely you are having some kind of problem with your throttle. |
#7
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"Dennis O'Connor" wrote in message
... Either the prop governor, or the piston in the hub are going to hell in a handbasket... The engine 'stalls' when the prop goes into feather - I doubt that there is an engine problem... Sending the governor out for overhual immediately, would be my inclination... Could also be the collar on the crankshaft where the oil gets injected to drive the prop. There was an article on this recently in "Light Plane Maintenance", but I can't put my hands on it right now. If the tolerance is a bit out, there could be a pressure loss sufficient to cause the prop to feather. -- Dr. Tony Cox Citrus Controls Inc. e-mail: http://CitrusControls.com/ |
#8
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Piston props (that i have flown) don't feather during shutdown...
It's tough to diagnose a problem on a complex system like a feathering, prop without being hands on, and without knowing the details of the feathering mechanism of the model of prop involved, but my initial inclination is still that it is governor or hub, not engine.... Since then I took a quick look at the commanche prop hub, and they have a pair of locks that prevent the blades from feathering when the rpm is below a certain rpm... Those locks are stuck open or damaged... However, the blades still wouldn't feather as long as the engine has enough oil pressure for the piston to overcome the feathering spring... Since he specifically said he had oil pressure at idle I still am very suspicious that the prop governor has an internal leak after it gets hot... Denny Actually, it may just be a bad idle mixture setting. My engine when hot used to stall at idle (frequently rolling out with the throttle at idle). I didn't have a twin, but I can imagine that the prop would feather during such a sequence in a twin. |
#9
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"Dennis O'Connor" wrote in message ...
Either the prop governor, or the piston in the hub are going to hell in a handbasket... The engine 'stalls' when the prop goes into feather - I doubt that there is an engine problem... Sending the governor out for overhual immediately, would be my inclination... snip First off, there is a mechanical high-pitch propeller stop that should be engaged somewhere 1500 rpm and disengaged 1500 rpm. This stop enables feathering in-flight, but should prevent it at engine shut-down. This mechanism has rather obviously failed. How come across it in the past several times, typically the prop feathers AFTER the engine is shut down. Also, if everything is working properly, the oil pressure delivered from the prop governor to the propeller should keep the propeller against the fixed low-pitch stop during un-"governed" operation. As in, unless the governor is sensing the engine rpm is too high (prop pitch too low) and starts to dump governed oil pressure, the propeller should stay in the low pitch setting. If the engine is not supplying sufficient oil volume to the governor, governor will not supply sufficient pressure to the propeller. With the propeller feathering at low/no rpm, it must be inspected/repaired. Then the first step in diagnosing a strange "governor" problem is ensuring that the proper amount of engine oil is present at the governor pad. The tooling to accomplish this also makes it easy to check the prop oil supply path from the other passage at the governor pad through the front main bearing to the prop galley in the crankshaft. TC |
#10
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wrote in message om... With the propeller feathering at low/no rpm, it must be inspected/repaired. Then the first step in diagnosing a strange "governor" problem is ensuring that the proper amount of engine oil is present at the governor pad. The tooling to accomplish this also makes it easy to check the prop oil supply path from the other passage at the governor pad through the front main bearing to the prop galley in the crankshaft. So how do you explain the engine stalling in addition to the feathering? |
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