Excellent information.  I will see if my prop cable is set so that I am unable to feather the prop intentionally.  I have copied the Hartzell manual for this prop and reproduce it here (the full manual is available online at hartzellprop.com):

B. Constant Speed, Feathering Propellers ( )HC-( )( )Y( )-2
(1) Refer to Figure 2-2. The -2 Series propellers are constant
speed propellers that use an air charge, spring, and
counterweights (if installed) to move the blades to high
pitch/feather position. Blade centrifugal twisting moment
acts to move the blades to low pitch, but the air charge,
spring, and counterweights overcome this force. Oil
pressure against a propeller mounted hydraulic piston
opposes the counterweight, spring, and air charge forces
to move the blades to low blade angle (low pitch).
(2) The action of the air charge, spring, and counterweights
tends to move the blades to a higher blade angle (high
pitch), reducing engine RPM. Oil pressure toward low
pitch increases engine RPM.
(3) If oil pressure is lost during operation, the propeller will
feather. Feathering occurs because the air charge, spring,
and blade counterweights are no longer opposed by
hydraulic oil pressure. The air charge, spring and blade
counterweights are then free to increase blade pitch to
the feathering (high pitch) stop.
(4) Normal in-flight feathering of these propellers is
accomplished when the pilot retards the propeller pitch
control past the feather detent. This allows control oil to
drain from the cylinder and return to the engine sump.
The engine can then be shut down.
(5) Normal in-flight unfeathering is accomplished when
the pilot positions the propeller pitch control into the
normal flight (governing) range and an engine restart is
attempted.
(6) Some aircraft are equipped with a hydraulic accumulator,
which stores a supply of oil under pressure. This oil
supply is released to unfeather the propeller during an
in-flight engine restart. Pressurized oil is directed to the
propeller, resulting in blade angle decrease. The propeller
begins to windmill, and engine restart is possible.
(7) When the engine is stopped on the ground, it is
undesirable to feather the propeller, as the high blade
angle inhibits engine starting. To prevent feathering during
normal engine shutdown on the ground, the propeller
incorporates spring energized latches. If propeller rotation
is approximately 800 RPM or above, the latches are
disengaged by centrifugal force acting on the latches
to compress the springs. When RPM drops below 800
RPM (and blade angle is typically within 7 degrees of the
low pitch stop), the springs overcome the latch weight
centrifugal force and move the latches to engage the high
pitch stops, preventing blade angle movement to feather
during normal engine shutdown.

My original intent with trying to feather the prop on the ground was to test the system for the ability to feather.  Of course, the down side of doing so is indicated in 7) above.  With a stopped engine and feathered prop on the ground you really can't get it restarted with the starter, the wind resistance prevents (or impedes) an engine start.  I had blade "twisters" on hand, just in case I was successful and the engine stopped. 

On close reading of the Hartzell manual it seems that in flight (glide) during an attempted restart with the starter turning the prop there is enough oil pressure to lift the feathered prop slightly off the "pegs."  This will start the prop windmilling. This should lead to a further rise in oil pressure to assist in the restart attempt.

Does your experience confirm this behavior?  I really appreciate you sharing this information with us.  I am not ready to repeat your testing, but I hope I can gather information to help me manage a bad situation, if it ever occurs.

Thanks.
Barry

On 6/22/2011 10:35 AM, liegner@earthlink.net wrote:

My governor is the same McCauley Prop Governor part #DCF290D7X/T3.
My Hartzell Prop Model is HC-H3YF-2UF-FC7693DF/SM17 (3 Blade Feathering Prop, Scimitar D-3273-2P).

The prop can be put into feather position on the ground if you maintain 1400-1600 minimum RPM with higher engine MAP (throttle control) than the usual idle settings.

While flying, the placement in full feather at idle will stop the prop (completely stationary).  It will not come out of feather without new cranking (I do not have an accumulator).

The engine can be restarted with the prop in feather by cranking it a bit more than usual, sending the blades into flatter pitch, given the crank more ability to turn the blades.  This occurs because crank yields engine oil pressure, and the governor amplifies pressure into the hub.  This can be demonstrated on the ground.

An inflight practice engine stoppage in full feather postion obviously requires a HOT START technique, but you don't have the same auditory clues (headset/ANR on, 120 KIAS), so one needs to study the guages for proper fuel/pressure indicators to guide the control choices (while you also fly the plane).

When you crank the engine inflight, your cranking electrical buss will be reduced in voltage as the starter pulls the amps.  If you have avionics on this same buss (especially a MFD or PFD), they will go dark during the restart, depriving you of the engine page you need to be watching.  That's quite startling at first.  When the prop begins its movement out of feather, the wind will catch it and it will begin to turn at ~400 RPM: you're almost there with the restart.

I first did this engine stoppage during HPAT recurrency training with Ron G (who also taught me his OSH hot start technique) so I could understand the glide performance of my Lancair IVP when engine broken.  I then practiced this a few more times afterwards, also to determine the power setting for a simulated engine out at an appropriate glide performance, again for more thorough practice (minus the actual stoppage).  Now I can simulate engine out more realistically with proper glide behavior (without actually stopping the engine).

I'm not sure about the prop's racing qualities or the two simultaneous occurances aspects of what you were told, as I was not told this.

I also don't understand how Hartzell could make a prop but not have a recommended Governor to govern it.

Our HPAT and LOBO instructors should continue to weigh in on the subject, as we all should keenly listen to their professional advice.  Disclaimer: I did not stay at a Holiday Inn last night.

Jeff L


Barry Knotts" <bknotts@buckeye-express.com> wrote:
Jeff,
I think I have the same full feathering Hartzell prop on my IV-P (HC-H3YF-2UF).   The governor is a McCauley #DCF290D7X/T3.  I can control the speed, but I can't feather this prop with the prop control.  I was told at one time that this prop is designed for racing and it only will go to full feather if two things occur simultaneously; loss of oil pressure and RPM above 1200.  Then it locks in feather and you do whatever you need to do to get on the ground.  The only way to unfeather it at that point requires attaining 1200 RPM WITH oil pressure.  Tough to do with the starter, the engine must start and produce oil pressure...while feathered.

These two things conditions for feathering should only occur together if you have a catastrophic loss of oil pressure with a windmilling prop (or driven).  Otherwise, you would have the prop feather every time you shut the engine down.

So my question is:  How did you get it to feather?  Do you have a different prop governor?  I called Hartzell once and they said that they did not have a recommended governor for the prop.  (That seemed a little strange.)

Inquiring minds....

Barry Knotts
Lancair IV-P, N4XE

On 6/19/2011 11:30 AM, liegner@earthlink.net wrote:
I have practiced engine out glide with my full feather three blade
Hartzell prop (Model number HC-H3YF-2UF) in the full feather position
and fully stopped.


--
For archives and unsub http://mail.lancaironline.net:81/lists/lml/List.html