A stopped, non feathered propeller is still very draggy compared to a feathered one.
Thank you @ Pilot_DAR for pointing this out.
Most MEPs if the failure is not due to the engine seizing, the propeller will windmill at an RPM well above the feather lock, probably around 1800 RPM. If there is a problem of oil pressure to the governor the fail safe is to push the propeller to coarse, in the absence of auto feather, but even in fail safe coarse, if the engine is not seized, it should be well above feather lock.
In the event you are around feather lock RPM in the air you have a serious governor failure or the engine is seizing. Pointing the nose down to Vne is not going to help.
There certainly is a difference in drag between feathered and unfeathered prop.
However, if an engine fails in cruise and above a certain altitude you might troubleshoot before feathering by trying to restart the engine.
That entails lowering the nose, which allows the prop to turn enough in the effective wind and the engine should start on the prop. Rather like the old pushing a car and dropping the clutch when its rolling when you have a flat battery (old school). So that would suggest to me that by lowering the nose one could increase the prop speed above the 800 or 900 rpm in order to feather it. Set against this is that it could not be done if the engine or hub had seized or if you were too low to get the nose down without ploughing into the ground by the time you reach feathering rpm.
For me there is no doubt that I can get a faster, cheaper to operate, cheaper to maintain single than I can a twin.
However, generally speaking a twin like the Aztec has take of and landing performance which will compete well against the equivalent single, and that goes for most twins versus their single counterpart. Secondly the twin version will usually have a better useful load.
The twin will usually be more stable in the cruise than the single. (I know several pilots who fly a twin because their wives start throwing up at the first sign of turbulence) I’m sure Peter knows one well.
On current terms I can buy a twin for less than the price of the single version and it will usually be better equipped for IFR flying.
But for me, and I have I think written this before, is the feel of the twin along with the comforting sense that the sound of those two engines gives me on a flight from Brittany to Devon or the mainland to Corsica.
I know the Mooney will get me there 10 minutes faster and cheaper, I know that I have a parachute to save the day in a Cirrus, and I know that engines rarely fail.
So I know its psychological.
Ted wrote:
Off course if it does stop, the majority of the reason for feathering now goes away. I.e drag from windmilling
I don’t quite agree. If the engine fails non mechanically (fuel exhaustion), it’s going to keep windmilling at flight speed, unless feathered. However, it may slow below 800-900 RPM while windmilling, particularly if set to coarse when the engine stopped. so now you’ve got a windmilling prop at 700RPM, which you cannot feather, which would be unhappy flying.
A stopped, non feathered propeller is still very draggy compared to a feathered one. I’ve done a fair amount of feather testing on PT6 turbines, where, with cautious engine control selection, you can feather a running engine. I’ve done this in the Caravan and Basler DC-3. Power lever to idle, wait for it to slow down, confirm engine operation by engine RPM and combustion temperature, and feather. Particularly in the Caravan, it’s like getting a big shove from behind. Then you have a luffing feathered prop, turning at only a few RPM. When you select out of feather, it’s like you touched the brakes, as the hardly turning feathered prop comes out of feather, and begins to turn first by windmiling, and then by engine power as the idling engine can overpower the feathered drag. Once the engine is driving the prop again, you have to prevent a prop overspeed, but otherwise it comes back to life normally. But you can feel the difference in drag between feathered and unfeathered with the prop hardly turning!
Pilot_DAR wrote:
“The propellers can be feathered only while the engine is rotating above 800 RPM. ….”
It’s 900rpm on the BE58
Which is why we study, and know our systems.
I assume any ful kno this if they have an MEP :)
Off course if it does stop, the majority of the reason for feathering now goes away. I.e drag from windmilling.
RobertL18C wrote:
because if you did blow a connecting road and the engine seized, unless you are flying a free turbine, the feather mechanism is unlikely to work
Which is why we study, and know our systems. For example: Piper PA-34-200, Emergency Procedures, Feathering Procedure:
“The propellers can be feathered only while the engine is rotating above 800 RPM. ….”
If the engine stops before you feather it, you’re not going to get it feathered. Otherwise, the props would feather every time you shut down the engines (and a PT6 landplane does, whether you select feather or not).
Malibuflyer wrote:
How long has the plane been grounded after that flight and which checks did the CAA require before it could be airworthy again?
It was never grounded, I was doing the certification testing for the IO-360 conversion to the DA-42. I shut down, feathered, unfeathered, and restarted many times for testing. Note the photo of the cockpit, DA42 mixture and propeller controls.
While not possible on a class rating (most class rating schools don’t use the SIM), during an ME/IR the ATO should be using the SIM to provide experience of realistic ‘insidious’ engine failure during an EFATO drill. A good SIM will provide a very good simulation of an MEP or MET failure which is not a stagey, obvious, catastrophic failure. In fact one might argue the simulated ‘instant’ EFATO used in a checkride, is potentially quite unrealistic, because if you did blow a connecting road and the engine seized, unless you are flying a free turbine, the feather mechanism is unlikely to work.
I did practice on xplane da62 during IRME training, but only for IR part. Somehow I don’t feel it’s helping on muscle memory, as there is no real effort on pedal and things are not really placed the same.
Do any of you guys use a sim to avoid or at least delay the rust?
I can practice on each flight I do (ok when I don’t have passengers to avoid scaring them off) but somehow I’m lazy 
