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  #11  
Old 12-11-2019, 01:03 PM
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airguy airguy is offline
 
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Location: Garden City, Tx
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Quote:
Originally Posted by Bavafa View Post
However, it does take a bit to get the prop to stop wind milling and that is the time that is spent during an emergency. It does take some practice, at least for me, to do that with the calm head. I have shut down my engine, even though high and above an airport, the rush and nervousness is still there.
In my airplane, I cannot stop the engine rotation even at stall speed with the prop in full coarse unless I close the throttle also. The difference in pumping losses across the throttle plate is that significant. With the throttle open, you are simply not going to stop it, not enough drag.

IO360 with Whirlwind CS.

If the engine fails down low and theres no time to jack with it, then yes just pull the blue knob back and fly the airplane into the crash. If you're up higher at a decent cruise altitude, then you have time to pull up and stop rotation, to improve sink rate and pick a landing site.
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  #12  
Old 12-11-2019, 01:23 PM
Canadian_JOY Canadian_JOY is offline
 
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Location: Ontario, Canada
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Quote:
Originally Posted by airguy View Post
If the engine fails down low and theres no time to jack with it, then yes just pull the blue knob back and fly the airplane into the crash. If you're up higher at a decent cruise altitude, then you have time to pull up and stop rotation, to improve sink rate and pick a landing site.
The most important message here is that your individual aircraft may vary. I know, for instance, that in my aircraft the altitude loss associated with trying to stop the prop is greater than the altitude loss associated with letting it windmill.

Know your airplane and fly it for what it is, not for what applies to somebody else's airplane.
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  #13  
Old 12-11-2019, 02:18 PM
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gmcjetpilot gmcjetpilot is offline
 
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The FAA handbook says, commercial single engine PTS now ACS (Airman Certification Standards) for power failure at altitude and associated emergency approach and landing procedures to "Configure the airplane in accordance with the POH/AFM and existing conditions." If the POH/AFM says to go to Low RPM/Coarse (Blue knob full aft/back) you have to do it on a check ride.

Some factory POH/AFM for complex planes with controllable pitch props do not mention this and therefore in a check ride you don't need to do this. However some examiners might ding you for that. Some POH/AFM do mention going to coarse/low RPM.

It has been awhile since I played with this. Coming into the pattern slow, power back, going to high RPM/fine pitch nothing happens, RPM stays the same, because Prop is already at fine pitch. I recall it would make a difference with engine at idle on a Piper Arrow. I am not sure you have enough oil pressure to make the prop move?
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Last edited by gmcjetpilot : 12-12-2019 at 10:04 AM.
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  #14  
Old 12-11-2019, 02:20 PM
Ralph Inkster Ralph Inkster is offline
 
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Location: Calgary, Alberta
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I agree with Canadian Joy.
In testing I stopped the prop, took slowing down to just over stall, than speeded up to a best glide speed-- the prop started windmilling again...
Best to just fly the plane to best glide speed and look for the best place to set it down (usually a spot right under you!). In that situation you will probably be so rattled, even the basics will be overload.
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Time to slow down the Builder Assist operation & concentrate on finishing my own stuff & fly the 6A.
My 'retirement' activities list;
Mon - 6 build project to finish
Tues - 6 upgrade project, canopy, panel, interior & fairings
Wed - 9A salvage rebuild, wing, firewall, gear, engine
Thurs - 7 salvage rebuild (was second plane I built, the Turbo Subie) for a buddy
Rest of week - belongs to the wife!

Last edited by Ralph Inkster : 12-11-2019 at 02:25 PM.
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  #15  
Old 12-11-2019, 04:43 PM
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DeeCee 57 DeeCee 57 is offline
 
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had an engine out experience a few years ago on a Falco equipped with a Lyco O-320 coupled to a Hartzell prop, pics here: http://www.aerofun.ch/falco-1.html
Conrod failure during climb out with associated oil loss. Prop kept windmilling and the resulting braking effect had us rejoin Terra Firma in a short time. The ROD was way higher than anticipated = rapidly diminishing options...

Still thanking my guardian angels
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  #16  
Old 12-11-2019, 05:13 PM
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Steve Melton Steve Melton is offline
 
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Zürich W, Switzerland, Europe, Earth, Milky Way, known Universe...

well said. it is estimated that the known universe is only 1%, the rest is unknown. some hypothesize the the big bang is a recurring cycle and we could be on the billionth big bang cycle. knowing this, we should all be flying more.

should I prime or not prime, that is the question.
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RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 800+ for all

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Last edited by Steve Melton : 12-11-2019 at 05:25 PM.
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  #17  
Old 12-11-2019, 06:39 PM
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scottmillhouse scottmillhouse is offline
 
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Default Test your plane

I did glide testing both ways, fine and coarse in my 9A with Hartselle CS with engine at idle. Coarse was actually a little worse, assumed not enough oil pressure to hold and it kept cycling from fine to coarse causing more drag. On my 7 I just did worse case glide tests at fine. Stopped a fixed pitch on my 12 and did not notice a significant increase in glide distance. As someone mentioned, probably lost any gains by slowing to near stall to stop the prop.
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  #18  
Old 12-12-2019, 10:06 AM
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gmcjetpilot gmcjetpilot is offline
 
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Quote:
Originally Posted by DeeCee 57 View Post
had an engine out experience a few years ago on a Falco equipped with a Lyco O-320 coupled to a Hartzell prop, Still thanking my guardian angels
WOW... Great job flying the plane to the ground. Beautiful Falco. Beautiful country to fly over. Glad you are OK.

Quote:
Originally Posted by Steve Melton View Post
Zürich W, Switzerland, Europe, Earth, Milky Way, known Universe... well said. it is estimated that the known universe is only 1%, the rest is unknown. some hypothesize the the big bang is a recurring cycle and we could be on the billionth big bang cycle. knowing this, we should all be flying more. should I prime or not prime, that is the question.
Pretty deep for RV forum and a slight thread drift, but 1%, my estimate is that is correct divide that by infinity (indeterminate). The theoretical physicist say a lot of things, because it is "SCIENCE!" Scientist are humans and have ego at play. I'm of the mind that what we do know about creation of earth, life on it and all that surrounds from solid scientific standpoint (Observable Phenomenon, Mathematics, Data supported by repeatable experiments) is infinitesimal. We may never know, except for theories, which is fine as long as those theories are not "believed" on faith only. Big fan of general and specific theories, but to your point we know little about the universe.
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Last edited by gmcjetpilot : 12-12-2019 at 10:16 AM.
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  #19  
Old 12-12-2019, 12:44 PM
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Steve Melton Steve Melton is offline
 
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Quote:
Originally Posted by gmcjetpilot View Post
Pretty deep for RV forum and a slight thread drift, but 1%, my estimate is that is correct divide that by infinity (indeterminate). The theoretical physicist say a lot of things, because it is "SCIENCE!" Scientist are humans and have ego at play. I'm of the mind that what we do know about creation of earth, life on it and all that surrounds from solid scientific standpoint (Observable Phenomenon, Mathematics, Data supported by repeatable experiments) is infinitesimal. We may never know, except for theories, which is fine as long as those theories are not "believed" on faith only. Big fan of general and specific theories, but to your point we know little about the universe.
matter and anti-matter. particles and anti-particles. per the laws of physics: if you prime there will be an equal and opposite aircraft that exists somewhere that is not primed.
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RV-9A, Tip-up, Superior O-320, roller lifters, 160HP, WW 200RV, dual impulse slick mags, oil pressure = 65 psi, EGT = 1300F, flight hours = 800+ for all

Simplicity is the art in design.

www.rvplasticparts.com
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  #20  
Old 12-13-2019, 10:08 PM
paul330 paul330 is offline
 
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My feeling is that it doesn't matter whether your aircraft glides 1.3nm/1000 or 1.5 - provided you know and train that way and know the correct techniques for judging and adjusting the glide profile. I can't imagine training with my prop way coarse because if you forget to put it to fine before a GA it is going to ruin your whole day.

There are, of course, certain situations where you require a better glide - a few miles off-shore or over inhospitable terrain for instance. In that case, I see nothing wrong with trying the coarse setting if there is some oil pressure to move the prop. But you are never going to make much difference. Maybe a couple of miles from 10,000'. Otherwise, I think it is preferable to concentrate on the landing rather that messing around with controls to achieve a questionable advantage.
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