I would think; that if there was an oil shortage problem to the engine or the prop gov, that the prop would feather by itself since there is no oil press pushing against the springs. Then the engine seizes. Or: maybe the single drive mag was not tight and advanced the timing to cause---- Just a thought
BH
PA-31 Chieftain Engine Failure
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black hole
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Re: PA-31 Chieftain Engine Failure
The old Boeing 377 had elecric props.
The average pilot, despite the somewhat swaggering exterior, is very much capable of such feelings as love, affection, intimacy and caring.
These feelings just don't involve anyone else.
These feelings just don't involve anyone else.
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Beefitarian
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Ok, maybe I'm just an ignorant fixed pitch prop PPL but, would it not be a good idea to pull the throttles, figure out which engine has gone fine and throttle up the good one? Instead of ducking and yelling, "Overspeed prop, TAKE COVER!!"everybody’s just along for the show as the overspeeding engine does what it’s going to do.
Colonel, old guys, what would you do if a prop suddenly went fine and you heard the rpm ramp up?
Re: PA-31 Chieftain Engine Failure
from a post on pprune
The Stratocruiser was offered with two types of propellers depending on the original customers specification, namely,
The Hamilton Standard Hydromatic or the Curtis Electric.
The main problem with the Curtis Electric (using a stephead electric motor to control blade pitch) was not the electric blade actuation (which was quite complicated, but reliable) but the hollow blades.
These were prone to blade fracture, which resulted in partial (usual case) blade separation, creating a terrible unbalanced condition, which can (and did) result in the engine being torn from its mounts.
Most original airlines that ordered the Stratocruiser with Curtis Electric props had the Hamilton Standard Hydromatic props fitted later.
The Hydromatic prop, if it loses prop govenor oil pressure, normally (but not always) will drift toward the low pitch (high RPM) blade position.
In order to feather this propellor, an electric motor driven pump was used.
It was called the feather pump, and supplied engine oil, under pressure to the prop, to drive the blades toward the feathered position.
IF the feather pump would not operate, the prop could absolutely NOT be feathered.
Therefore, if normal prop govenor oil pressure was lost, the result could well lead to a runaway condition, and the feather pump was used to feather the propeller.
However, if a runaway prop could not be feathered, either because the feather pump could not supply sufficient oil pressure, the pump failed to operate or the oil supply to the pump (or the propeller) was interrupted, the EMERGENCY procedure was to pull the respective engine fire handle (to, among other things, cut off oil to the engine), in hopes of causing the engine to seize, because....the airplane could not maintain altitude with one prop windmilling (runaway prop) at heavy weights.
Even at lighter weights, the ability to maintain altitude was limited, and in any case, the anticipated range (as in an ocean crossing) in such a condition would be severely compromised.
The Stratocruiser was offered with two types of propellers depending on the original customers specification, namely,
The Hamilton Standard Hydromatic or the Curtis Electric.
The main problem with the Curtis Electric (using a stephead electric motor to control blade pitch) was not the electric blade actuation (which was quite complicated, but reliable) but the hollow blades.
These were prone to blade fracture, which resulted in partial (usual case) blade separation, creating a terrible unbalanced condition, which can (and did) result in the engine being torn from its mounts.
Most original airlines that ordered the Stratocruiser with Curtis Electric props had the Hamilton Standard Hydromatic props fitted later.
The Hydromatic prop, if it loses prop govenor oil pressure, normally (but not always) will drift toward the low pitch (high RPM) blade position.
In order to feather this propellor, an electric motor driven pump was used.
It was called the feather pump, and supplied engine oil, under pressure to the prop, to drive the blades toward the feathered position.
IF the feather pump would not operate, the prop could absolutely NOT be feathered.
Therefore, if normal prop govenor oil pressure was lost, the result could well lead to a runaway condition, and the feather pump was used to feather the propeller.
However, if a runaway prop could not be feathered, either because the feather pump could not supply sufficient oil pressure, the pump failed to operate or the oil supply to the pump (or the propeller) was interrupted, the EMERGENCY procedure was to pull the respective engine fire handle (to, among other things, cut off oil to the engine), in hopes of causing the engine to seize, because....the airplane could not maintain altitude with one prop windmilling (runaway prop) at heavy weights.
Even at lighter weights, the ability to maintain altitude was limited, and in any case, the anticipated range (as in an ocean crossing) in such a condition would be severely compromised.
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Beefitarian
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Whoa! That's really interesting rigpiggy, definitely serious and a bit frightning.
I wonder if there are many documented stories about pilots having to try it and the out come. I suppose lacking cockpit voice recorders and possibly even any wreckage found back then, there are probably a few that just ended up being described as, "Lost at sea."
The fuselage and window seat in that picture you started with look pretty bad. Yet it seems like it must have worked out fairly good over all, since the plane seems to be parked somewhere.
I wonder if there are many documented stories about pilots having to try it and the out come. I suppose lacking cockpit voice recorders and possibly even any wreckage found back then, there are probably a few that just ended up being described as, "Lost at sea."
The fuselage and window seat in that picture you started with look pretty bad. Yet it seems like it must have worked out fairly good over all, since the plane seems to be parked somewhere.
Re: PA-31 Chieftain Engine Failure
rigpiggy, you just about described the same type of problem with the Dowty prop in the Gulfstream 1 turboprop except they had pitch locks that restricted prop pitch in cruise to limit RPM to 16,200 from the normal max of 15,000 (Engine RPM). In the sim, we experienced a prop failure and it took both pilots standing on the rudder to maintain directional control.
Pulling the fire T handles was supposed to shut off fuel, hydraulics and electrics but did not shut off oil supply to seize the engine.
One article I read many moons ago gave the amount of power required to overcome prop drag and a windmilling prop coupled to the engine was the highest IIRC.
Pulling the fire T handles was supposed to shut off fuel, hydraulics and electrics but did not shut off oil supply to seize the engine.
One article I read many moons ago gave the amount of power required to overcome prop drag and a windmilling prop coupled to the engine was the highest IIRC.
The average pilot, despite the somewhat swaggering exterior, is very much capable of such feelings as love, affection, intimacy and caring.
These feelings just don't involve anyone else.
These feelings just don't involve anyone else.
Re: PA-31 Chieftain Engine Failure
Rigpiggy.. Thanks for the clarification. The few examples of round engine era aircraft I've had my hands on didn't happen to have a firewall shutoff valve for the engine oil. Would certainly be a nice thing to have, rather than potentially feeding a fire with an additional 30 gallons of oil.
Hell of an SOP to have to resort to!
Hell of an SOP to have to resort to!
