ROP v. LOP

[jlunseth]

For all you ROP v. LOPers out there, https://www.advancedpilot.com/livesignup.html.  Coming up mid-March.  Go.  See an actual engine running on an actual test stand and then make up your mind.  The food and company are pretty good too.

And you thought I was going to start an argument, er, debate, er, discussion.  You know what I mean.

[MooneyMitch]

Oh no!!!!!!   

[201er]

1 hour ago, jlunseth said:

For all you ROP v. LOPers out there, https://www.advancedpilot.com/livesignup.html.  Coming up mid-March.  Go.  See an actual engine running on an actual test stand and then make up your mind.  The food and company are pretty good too.

And you thought I was going to start an argument, er, debate, er, discussion.  You know what I mean.

I fly a Mooney LOP, like heck I'm gonna drop a grand to be convinced of what I know!

[gsxrpilot]

I don't have near the experience of 201er or many on this board, but for me, that $1AMU was the best money I've spent in aviation since becoming an owner. 

The LOP thing is a big part, but not the most valuable part of the class, in my opinion. The best part for me was really learning how to use and read my engine monitor. The confidence and ability to diagnose and understand a long list of issues, just from reading the engine monitor in flight is priceless.

[Bob_Belville]

LOP looking good this afternoon. Spread was 0.3 gph and cyls were -35 to -60 LOP. 8.3 gph, probably cost 10 ktas vs. ROP.

[Mcstealth]

I read the title, and said uh- oh......

[jlunseth]

1 hour ago, Mcstealth said:

I read the title, and said uh- oh......

A title is just a title.  I am not taking a position.  And here you guys thought I was going to start an argument.

Just go learn, and for those of you who already know how, stay home and play with the kids, or your airplane, or ... well I ain't going there either. 

[jlunseth]

I like the icicle display.  I don't make much use of it anymore though, too much fiddling to get there.  I just make my LOP setting and it works

[M20F]

ROP/LOP, real men just fly PEAK!

[Guitarmaster]

ROP/LOP, real men just fly PEAK!

I just read that in Tim Allen's voice.

Sent from my XT1585 using Tapatalk

[Cyril Gibb]

On 2017-02-13 at 3:39 PM, jlunseth said:

For all you ROP v. LOPers out there, https://www.advancedpilot.com/livesignup.html.  Coming up mid-March.  Go.  See an actual engine running on an actual test stand and then make up your mind.  The food and company are pretty good too.

And you thought I was going to start an argument, er, debate, er, discussion.  You know what I mean.

A question related to the very lucky outcome of the CO poisoning event we heard about.  If CO is the result of incomplete combustion due to lack of oxygen in a rich fuel mixture, does that mean that CO production at LOP is minimal?  Do the advancedpilot guys have CO results for LOP/ROP?. I'm a LOPer, and this may add an additional data point to my preference.

[mooniac15u]

5 minutes ago, Cyril Gibb said:

A question related to the very lucky outcome of the CO poisoning event we heard about.  If CO is the result of incomplete combustion due to lack of oxygen in a rich fuel mixture, does that mean that CO production at LOP is minimal?  Do the advancedpilot guys have CO results for LOP/ROP?. I'm a LOPer, and this may add an additional data point to my preference.

CO production will be less in a leaner combustion mixture than a richer mixture.  It is virtually impossible to completely eliminate CO production during combustion.

[jlunseth]

1 hour ago, Cyril Gibb said:

A question related to the very lucky outcome of the CO poisoning event we heard about.  If CO is the result of incomplete combustion due to lack of oxygen in a rich fuel mixture, does that mean that CO production at LOP is minimal?  Do the advancedpilot guys have CO results for LOP/ROP?. I'm a LOPer, and this may add an additional data point to my preference.

I would not count on that.  As mooniac15 said, CO may be reduced but not eliminated.  One issue with piston engine combustion is the very brief period for combustion to occur.  Regardless of how well the full and air are mixed, some unburned mix will always occur, and that causes CO.  At any rate, I don't recall the APS guys saying anything about CO risk being eliminated by LOP ops during the seminar

[Brandontwalker]

1 hour ago, Cyril Gibb said:

A question related to the very lucky outcome of the CO poisoning event we heard about.  If CO is the result of incomplete combustion due to lack of oxygen in a rich fuel mixture, does that mean that CO production at LOP is minimal?  Do the advancedpilot guys have CO results for LOP/ROP?. I'm a LOPer, and this may add an additional data point to my preference.

OMG!  You just discovered a new debate point for LOP v. ROP that has not been beat to death!  Break out the gloves fellas.

[Bob - S50]

8 hours ago, jlunseth said:

I would not count on that.  As mooniac15 said, CO may be reduced but not eliminated.  One issue with piston engine combustion is the very brief period for combustion to occur.  Regardless of how well the full and air are mixed, some unburned mix will always occur, and that causes CO.  At any rate, I don't recall the APS guys saying anything about CO risk being eliminated by LOP ops during the seminar

Here are a couple graphs I found on Beechtalk:

The red line is approximate TIT.

And this one:

Edited February 17, 2017 by Bob - S50

[201er]

Don't let marauder hear you bringing up tits!

Edited February 17, 2017 by 201er

[jetdriven]

On 2/13/2017 at 5:13 PM, Bob_Belville said:

LOP looking good this afternoon. Spread was 0.3 gph and cyls were -35 to -60 LOP. 8.3 gph, probably cost 10 ktas vs. ROP.

You may be a little leaner than best economy. Somwhere near where you are, airspeed takes a tremendous hit for each .1 gph saved. Iirc it was around 25-35 ish LOP was the best efficiency before the massive drop. 

[Shadrach]

Bob beat me to it. As mixture is leaned beyond peak, CO levels drop dramatically. NOx increases before dropping off again. If I discovered I had a CO leak in flight while running ROP, I surely would lean past stoic. 

[201er]

Ok, I'm sold on flying LOP just to avoid CO! (I promise it has nothing to do with being cheap on fuel or preferring cooler temps) 

Edited February 17, 2017 by 201er

[Greg_D]

A guy posted a panel pic of his Ovation in cruise on FaceBook the other day.  He was ROP, burning over 16GPH and had cylinder head temps around 380.  I suggested he might want to try running LOP, not to save fuel, but to be nicer to the engine.  Hard to believe, but there are still naysayers out there.  One guy commented that the pictured EGT was high enough and that going LOP was "hotter".  

He also mentioned that the Mooney POH stated that LOP was not recommended.  Has anyone ever seen that in a Mooney POH?

[carusoam]

Our resident chemist gave some good insight about the possibility of CO not being eliminated by going LOP...

Add this to the pile, being short of excess O₂ is a driving force for not producing CO₂.  Expect that running LOP (excess O₂₎ and completing the burn inside the cylinder is better than having a few percentages of half burnt things thrown down the cracked exhaust pipe...

Unfortunately, the OP's challenge occurred during the very rich, kinda slow climb.

It would take an exhaust monitor to demonstrate the percentages of by-products we actually see during the peak or LOP flight.  Interesting challenge for the APC guys, no?

You wouldn't want to breathe any of this stuff if given the choice.  There aren't enough anti-oxidants in a grocery store for that.

Best regards,

-a-

Edited February 17, 2017 by carusoam

[kortopates]

7 minutes ago, Greg_D said:

A guy posted a panel pic of his Ovation in cruise on FaceBook the other day.  He was ROP, burning over 16GPH and had cylinder head temps around 380.  I suggested he might want to try running LOP, not to save fuel, but to be nicer to the engine.  Hard to believe, but there are still naysayers out there.  One guy commented that the pictured EGT was high enough and that going LOP was "hotter".  

He also mentioned that the Mooney POH stated that LOP was not recommended.  Has anyone ever seen that in a Mooney POH?

Ask him what is Best Economy mixture as defined by Engine manufacturers today and in modern POH's? 

[carusoam]

Greg,

the O1 POH doesn't scream fly LOP because it is good for the engine.

It clearly does give engine settings that are LOP.

It also Says Concorde batteries are standard equipment, and Gills are acceptable substitutes.

It takes being on MS to make sense of this, where things can mostly be hashed out with some facts and data.  And some humor thrown about...

Best regards,

-a-

Edited February 17, 2017 by carusoam

[Bob_Belville]

9 hours ago, jetdriven said:

You may be a little leaner than best economy. Somwhere near where you are, airspeed takes a tremendous hit for each .1 gph saved. Iirc it was around 25-35 ish LOP was the best efficiency before the massive drop. 

Byron, that's my experience as well, speed drops off before engine runs rough. This was a local test flight, I wasn't going anywhere, just checking GAMI spread. I milked fuel last year to get to KOSH nonstop with my E that only holds 52 (54?) gallons. 8.3 gph was a sweet spot, about 62% power.

[201er]

20 minutes ago, Bob_Belville said:

Byron, that's my experience as well, speed drops off before engine runs rough. This was a local test flight, I wasn't going anywhere, just checking GAMI spread. I milked fuel last year to get to KOSH nonstop with my E that only holds 52 (54?) gallons. 8.3 gph was a sweet spot, about 62% power.

That probably puts you close to Carson's speed and that's why it is so efficient.