VansAirForceForums  
Home > VansAirForceForums

-POSTING RULES
-Advertise in here!
- Today's Posts | Insert Pics

Keep VAF Going
Donate methods

Point your
camera app here
to donate fast.


Go Back   VAF Forums > Main > Safety
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read

Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 06-15-2021, 12:05 PM
wawrzynskivp wawrzynskivp is offline
 
Join Date: Feb 2018
Location: Incline Village Nv
Posts: 86
Default CS Props/Eng Combos that are controllable eng OUT

Resultant Feedback:
1. Electrically controlled props
2. MT Three Blade MTV-12-B/183-59b, on YIO 390 down to 80 Kts
3. IO-360A1B6 with non-aerobatic Hartzell prop and MT Governor down to 80 Kts
4. 0 320 with a Hartzell prop with the MT gov

Looks like the common thread on a non-aero CS hydraulic prop is an MT governor. My understanding is that the governor is both a regulator and an oil pressure booster. So perhaps the MT governor has a higher oil pressure output at lower RPMs than other governors.

Would be nice to have a prop person like the folks at Catto weigh in.

Original question:


Hello All,

I would like to try to harvest some anecdotal information and repost a summary of which CS props and engine combinations yield control in engine out scenarios.

If you have done true no engine power testing (Not idle, but truly no power) and found that you can still control your prop to the course position please post your prop/governor/engine and lowest observed controllable airspeed in Knots.

Ideally a builder could consider this aspect of extended glide as worth one prop combo or another.

Last edited by wawrzynskivp : 06-17-2021 at 04:53 PM.
Reply With Quote
  #2  
Old 06-15-2021, 02:01 PM
PerfTech's Avatar
PerfTech PerfTech is offline
 
Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,520
Default

Quote:
Originally Posted by wawrzynskivp View Post
Hello All,

I would like to try to harvest some anecdotal information and repost a summary of which CS props and engine combinations yield control in engine out scenarios.

If you have done true no engine power testing (Not idle, but truly no power) and found that you can still control your prop to the course position please post your prop/governor/engine and lowest observed controllable airspeed in Knots.

Ideally a builder could consider this aspect of extended glide as worth one prop combo or another.
... Aerobatic C/S propellers all automatically go to course pitch on engine stoppage. Thanks, Allan
__________________
Allan Nimmo
AntiSplatAero.com
Innovative Aircraft Safety
Products, Tools & Services
Info@AntiSplatAero.com
Southern California (KREI)
RV-9A / Edge-540
(909) 824-1020
Reply With Quote
  #3  
Old 06-15-2021, 02:04 PM
FORANE's Avatar
FORANE FORANE is offline
 
Join Date: Nov 2011
Location: East TN
Posts: 599
Default

Electric props are controllable.
__________________
Lancair 235/340
RV-9A (2013 - 2016)
Reply With Quote
  #4  
Old 06-15-2021, 04:30 PM
skylor's Avatar
skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 1,000
Default Aerobatic Props

Quote:
Originally Posted by PerfTech View Post
... Aerobatic C/S propellers all automatically go to course pitch on engine stoppage. Thanks, Allan
This is not exactly true. The "counterweighted" aerobatic props are designed to go to coarse pitch upon loss of oil pressure, but if the engine stops producing thrust while maintaining oil pressure the prop will continue to "govern"...

With that said, my IO-360A1B6 with non-aerobatic Hartzell prop and MT Governor (circa 2006) is fully controllable in a true engine-out glide. I have tested this down to ~ 80 KIAS. At 100 KIAS, the difference between prop lever forward and prop lever aft is ~1500 RPM/~600 RPM.

Skylor

Last edited by skylor : 06-15-2021 at 04:37 PM.
Reply With Quote
  #5  
Old 06-15-2021, 04:45 PM
swjohnsey swjohnsey is offline
 
Join Date: Nov 2018
Location: Kingsville, TX
Posts: 354
Default

Quote:
Originally Posted by skylor View Post
This is not exactly true. The "counterweighted" aerobatic props are designed to go to coarse pitch upon loss of oil pressure, but if the engine stops producing thrust while maintaining oil pressure the prop will continue to "govern"...

With that said, my IO-360A1B6 with non-aerobatic Hartzell prop and MT Governor (circa 2006) is fully controllable in a true engine-out glide. I have tested this down to ~ 80 KIAS. At 100 KIAS, the difference between prop lever forward and prop lever aft is ~1500 RPM/~600 RPM.

Skylor
How did you test that?
Reply With Quote
  #6  
Old 06-15-2021, 04:49 PM
PerfTech's Avatar
PerfTech PerfTech is offline
 
Join Date: Sep 2010
Location: Redlands, Ca.
Posts: 1,520
Default

Quote:
Originally Posted by skylor View Post
This is not exactly true. The "counterweighted" aerobatic props are designed to go to coarse pitch upon loss of oil pressure, but if the engine stops producing thrust while maintaining oil pressure the prop will continue to "govern"...

With that said, my IO-360A1B6 with non-aerobatic Hartzell prop and MT Governor (circa 2006) is fully controllable in a true engine-out glide. I have tested this down to ~ 80 KIAS. At 100 KIAS, the difference between prop lever forward and prop lever aft is ~1500 RPM/~600 RPM.

Skylor
....I was referring to prop stopped, and the hub with the spring reversed. You have zero RPM prop stopped.
__________________
Allan Nimmo
AntiSplatAero.com
Innovative Aircraft Safety
Products, Tools & Services
Info@AntiSplatAero.com
Southern California (KREI)
RV-9A / Edge-540
(909) 824-1020
Reply With Quote
  #7  
Old 06-15-2021, 04:51 PM
skylor's Avatar
skylor skylor is offline
 
Join Date: Aug 2009
Location: Southern California
Posts: 1,000
Default

Quote:
Originally Posted by swjohnsey View Post
How did you test that?
While well above an airport, I established a glide at idle, then pulled the mixture to ICO. When finished with the test point, advancing the mixture then throttle results in immediate power.

Skylor
Reply With Quote
  #8  
Old 06-15-2021, 04:59 PM
swjohnsey swjohnsey is offline
 
Join Date: Nov 2018
Location: Kingsville, TX
Posts: 354
Default

So the engine was still turning and producing oil pressure? I have similar setup, IO-360 with Hartzell CS.
Reply With Quote
  #9  
Old 06-16-2021, 05:25 AM
David Z David Z is offline
 
Join Date: Aug 2010
Location: Thunder Bay Ontario
Posts: 738
Default

As long as the engine is turning, the oil pump and governor will be able to control a hydraulically actuated prop. This goes for windmilling too as the pumps and accessories don't know what the source of engine rotation.
__________________
RV8
Empennage Passed Pre-close Inspection
Wings mostly done
Fuselage at the "porcupine stage"
83126
Dash 8 day job is financing the RV8
Donation till September 2022
Reply With Quote
  #10  
Old 06-16-2021, 09:10 AM
rvbuilder2002's Avatar
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 9,560
Default

Quote:
Originally Posted by David Z View Post
As long as the engine is turning, the oil pump and governor will be able to control a hydraulically actuated prop. This goes for windmilling too as the pumps and accessories don't know what the source of engine rotation.
This is not universally true.

We have done engine off glide testing in the RV-10 and RV-14 demonstrators and I can say for certain (I was pilot for the tests on the RV-10) that on our RV-10, prop control position made zero difference on decent rate or RPM. I think that was the case for the RV-14A as well.

I have read reports that I consider reliable, of tests that did indicate that pulling the blue knob increase glide performance, so I don't know what factors are in play when it doesn't. My guess would be that it is related to what the minimum RPM is that you can control the propeller while the engine is running. If the wind milling RPM is below this value, pulling the blue knob on a wind milling engine will have no effect.

So I suggest not assuming that it will help, but I know of no down side to doing it, in case it will.
__________________
Opinions, information and comments are my own unless stated otherwise. They do not necessarily represent the direction/opinions of my employer.

Scott McDaniels
Hubbard, Oregon
Van's Aircraft Engineering Prototype Shop Manager
FAA/DAR
RV-6A (aka "Junkyard Special ")
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 07:46 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.