What are the effects when one shuts down a turbo prop engine before feathering?

Question

What are the effects when one shuts down a turbo prop engine before feathering?

Answer 1

If in flight, just as gbrljl says. huge drag from the windmilling prop- so much so that in some cases it's impossible to keep control & you'll likely be explaining to a somewhat higher authority than the CAA. Then there can be damage to the gearing system etc. Some props these days automatically go to feather as the engine is shut down and oil pressure to the prop hub is lost.

Edit: It's called a spring . . .

Answer 2

The propeller will wind-mill and increase drag on the aircraft(if twin engine) on the side of the shut down engine....thus putting a heavier load on the operating engine. Also the reduction gearing may be damaged and possibly the turbine engine itself if the situation is not corrected.

Answer 3

So if you shut down the engine before feathering, where are you going to get the oil pressure from to feather the prop?

Answer 4

No it has no effect. We feather to perevent windmilling durning parking. Megagoat there are no valves, guides or seats in a turbine and no the propfasteners willl be just fine.

Answer 5

The turbo remains hot and can be damaged.

Answer 6

Hi Abubaker... It increases the head pressure on the exhaust valves, guides, and seats...Also the crankshaft bearings and all prop fasteners will suffer fatigue...KTnTexas

Open Skies...KTnTexas

Answer 7

Not all props on turboprop engines are feathered on shutdown.  Some Garrett engines do not feather.  It could even be "most" or "all", but I do not have Garrett time, so I don't want to mislead you.

PT6 engines (one of the most popular) do feather on shutdown.  They have a "free turbine" design, meaning the power shaft and compressor shaft are not physically connected.  The power shaft is attached to a reduction gearbox, which then turns the prop.  If the propeller is not feathered on shutdown, inertia will continue to turn the propeller/gearbox/turbine assembly.  Also, the wind may turn this assembly if the engine is shut down and the prop is not feathered.

Here's the problem.  The accessory section is driven off of the compressor shaft.  One of the things on the accessory section is the oil pump.  Since the compressor shaft and the power shaft are not interconnected, the compressor shaft will stop rotating almost immediately.  If the power shaft is rotating due to inertia or windmilling of an unfeathered prop, that whole assembly, including the reduction gearbox, is spinning without oil being delivered from the accessory section.  Metal on metal without oil is not a good thing.

EDIT: my answer was assuming you were asking about a normal shut down on the ground, not an in-flight shutdown.

Answer 8

On aircraft like the Lockheed P-3 Orion and the C-130 Hercules the Props are always left unfeathered during engine shutdown after each flight.  If you are talking about engine shut down procedures during flight and the prop fails to feather, then you would have severe directional control problems