Power setting LOP

[A64Pilot]

48 minutes ago, Shadrach said:

That article is a good read. That being said, leaning to 100ROP  at 3000’ in the climb is too aggressive in my opinion. That’s well above 90% power.

In theory though it should be OK.

That’s one theory and one should be, unfortunately should bees don’t make honey  

The issue is as I see it is say just for arguments sake you save 2 GPH for 5 min, because I doubt many would be concerned with 100 ROP above 7,000 or so and surely you can get from 3 to 7 in 5 min.

So by leaning at 3000 instead of 7000, in that 5 min you save a whopping .17 gl. If I did the math right, but say your cruise climbing at half the climb rate, then you save a whopping .34 gl.

If that’s the article I think it is, I concur with climbing at higher airspeed, what I call cruise climb, not climb at cruise power, that’s foolish for several reasons, unless of course it’s a small climb and not worth reconfiguring, waking up the Wife whatever.

 

[A64Pilot]

For everyone.

The Angle valve IO-360 is THE poster child for LOP, seemingly right out of the box most will run so far LOP that they won’t make enough power to fly, yet they will still be smooth.

Most GA flat motors won’t, some can be massaged by swapping injectors around or playing games with carb heat and Gami injectors, and some just won’t, no matter how perfect you get the “Gami” spread.

My IO-540W1A5D just wouldn’t, not really, at some altitudes and on some days it would, barely.

The IO-520 in the C-210 would and it did save some fuel, but was 10 kts slower than it was at best power.

[PT20J]

The carbureted O-320 in a Piper Warrior will run LOP. There is even a procedure in the POH for doing so including such APS concepts at WOT and BMP. 

Many Lycomings run better LOP that many Continentals because the intake tubes are symmetrical and of equal length and they run through the sump which warms the intake air slightly decreasing thermal efficiency but aiding in mixture consistency.

WOT LOP_20190615_0001.pdf

[Jetpilot86]

Did another test flight last night. I’ve got a bad EGT probe that DMax has to deal with in a few weeks but my 30 SFOH Bravo engine had all the rest of the EGT’s peak within a second of each other, at best a .2 spread. I’m assuming I have non-GAMI’s. I only ran that way for a couple minutes, but ran nice and smooth at 27”/2300 Key #50 @ 9500’, 10dF LOP as well. 165ktas just under 15gph. 382°F was the max CHT on #6 Oil was 190° & TIT was 1590°. Before, running 2200RPM, felt LOP was “rougher” running.  Looking forward to more experiments once the Gee-Bee baffles are installed at annual, and I swap to some FineWires. Thinking I may not need GAMI’s just yet. 

Edited January 6 by Jetpilot86
C, F whichever ;-)

[Fly Boomer]

4 minutes ago, Jetpilot86 said:

382°C was the max CHT on #6

Seems unlikely.

[Shadrach]

6 minutes ago, Fly Boomer said:

Seems unlikely.

Yeah, let’s hope not.

[Shadrach]

14 hours ago, PT20J said:

The carbureted O-320 in a Piper Warrior will run LOP. There is even a procedure in the POH for doing so including such APS concepts at WOT and BMP. 

Many Lycomings run better LOP that many Continentals because the intake tubes are symmetrical and of equal length and they run through the sump which warms the intake air slightly decreasing thermal efficiency but aiding in mixture consistency.

WOT LOP_20190615_0001.pdf 568.62 kB · 8 downloads

I read the doc and I am not seeing the BMP. It says to lean at full throttle from full rich through peak RPM until the desired RPM is reached. It also says to avoid remaining at or above 75% for more than 15 secs (that’s an eternity to get past peak) at any setting other than full rich. As I read it, this process does not guarantee that the engine is lean of peak EGT; it guarantees that the engine is lean of peak power. 
 

I have always found the power charts for different NA engines curious. This POH says the engine won’t make 75% power above 6500’.

My POH say that my engine will make 77% power at 10,000’ on a warmer than standard day temperature.

 

[PT20J]

I think the BMP is implied by the fact that they are telling you to set power with mixture and not dawdle above 75% power when you do it.

 

[Shadrach]

59 minutes ago, Jetpilot86 said:

Did another test flight last night. I’ve got a bad EGT probe that DMax has to deal with in a few weeks but my 30 SFOH Bravo engine had all the rest of the EGT’s peak within a second of each other, at best a .2 spread. I’m assuming I have non-GAMI’s. I only ran that way for a couple minutes, but ran nice and smooth at 27”/2300 Key #50 @ 9500’, 10dF LOP as well. 165ktas just under 15gph. 382°F was the max CHT on #6 Oil was 190° & TIT was 1590°. Before, running 2200RPM, felt LOP was “rougher” running.  Looking forward to more experiments once the Gee-Bee baffles are installed at annual, and I swap to some FineWires. Thinking I may not need GAMI’s just yet. 

One of the unique things about the TIO-540-AF1B compared to other turbocharged engines is its more thermally efficient 8:1 compression ratio which should yield lower raw TITs, making more mixture options available to the pilot.

[Shadrach]

On 1/5/2024 at 7:35 PM, A64Pilot said:

In theory though it should be OK.

That’s one theory and one should be, unfortunately should bees don’t make honey  

The issue is as I see it is say just for arguments sake you save 2 GPH for 5 min, because I doubt many would be concerned with 100 ROP above 7,000 or so and surely you can get from 3 to 7 in 5 min.

So by leaning at 3000 instead of 7000, in that 5 min you save a whopping .17 gl. If I did the math right, but say your cruise climbing at half the climb rate, then you save a whopping .34 gl.

If that’s the article I think it is, I concur with climbing at higher airspeed, what I call cruise climb, not climb at cruise power, that’s foolish for several reasons, unless of course it’s a small climb and not worth reconfiguring, waking up the Wife whatever.

 

5 pages of:

…” don’t run high power LOP because it’s dangerous”

…” Lycoming/Continental say you can’t hurt your engine below 75/65% so don’t lean above that depending on the make of your engine.

…”You can do it but not unless you really pay attention”

And then on page six: 

…”Leaning to 100ROP at >90% power at cruise climb airspeeds is just fine”.

 

 

[BlueDun]

On 1/3/2024 at 9:55 AM, T. Peterson said:

I really like your simple approach. A lot on this thread just makes me dizzy!

 I very interested in the Ovations and am about to put up my 231 for sale, however I am very curious about the speed/efficiency gains and losses I can expect from such a move.

What is your TAS at 13 to 13.5 gph? And at what altitude? One of the reasons I want a normally aspirated engine is because I never fly above 12000 feet, but I do want speed and efficiency (who doesn’t!) I think the IO 550 will give me the best performance compromises, but I assumed that it would cost me 15 to 16 gph to get 175 kts vs the 12.5 to 13.0 I currently spend to achieve 160 kts.

Sorry for delay responding, @T. Peterson. Attached are settings from a recent flight at 13 gph LOP, 2400 RPM at 8,000 feet. That gave me 169/170 TAS. That same day I was 165 kt at 12.5 gph.

Specifically, I was wide open throttle on a high pressure day of 30.08 and it was 5 C colder than standard.

At 10,000' I am at 170 TAS or so with 12.5 gph. At 13 gph I am in low 170s.

Keep in mind that I have speed penalty of at least a couple knots because I have both air conditioning and FIKI. It was later not a factory option to get both.

Ovation 3, IO-500-N, 3-blade Hartzell, air conditioning, FIKi, G1000 WAAS.

 

 

 

[A64Pilot]

5 hours ago, Shadrach said:

5 pages of:

…” don’t run high power LOP because it’s dangerous”

…” Lycoming/Continental say you can’t hurt your engine below 75/65% so don’t lean above that depending on the make of your engine.

…”You can do it but not unless you really pay attention”

And then on page six: 

…”Leaning to 100ROP at >90% power at cruise climb airspeeds is just fine”.

 

 

Again you misquote me

This IS what I posted

On 1/5/2024 at 7:35 PM, A64Pilot said:

In theory though it should be OK.

That’s one theory and one should be, unfortunately should bees don’t make honey  

 

I assume you must have reading comprehension issues as most can see pretty obviously that I’m not saying it’s just fine.

Then went on to explain how little fuel you would save by doing so, which anyone without comprehension issue can see I’m saying it’s foolish. There is risk, with an insignificant gain

[Jetpilot86]

5 hours ago, BlueDun said:

Sorry for delay responding, @T. Peterson. Attached are settings from a recent flight at 13 gph LOP, 2400 RPM at 8,000 feet. That gave me 169/170 TAS. That same day I was 165 kt at 12.5 gph.

Specifically, I was wide open throttle on a high pressure day of 30.08 and it was 5 C colder than standard.

At 10,000' I am at 170 TAS or so with 12.5 gph. At 13 gph I am in low 170s.

Keep in mind that I have speed penalty of at least a couple knots because I have both air conditioning and FIKI. It was later not a factory option to get both.

Ovation 3, IO-500-N, 3-blade Hartzell, air conditioning, FIKi, G1000 WAAS.

 

 

 

When I did my insurance checkout for my Bravo in a G1000 Bravo, i just cringed at how much wasted space there was on that left PFD.  Admittedly, I'm used to a PFD/MFD combo right in front of me and just didn't like having to look "so far" over at that middle screen for NAV stuff.  Liked the G1000 best in Emergency Mode where I ended up with the PFD/NAV stuff right in front of me.  However, there a definitely a few things I don't have in my G600, that are on the G1000 I wish I did have...

[Echo]

Ross,

Please do a power discussion dedicated exclusively to the IO-360 power plant in the vintage section.  I would value your concise discussion without the buzz of the bees and the whup whup of the chopper.  I appreciate you.

[Pinecone]

On 1/6/2024 at 1:23 PM, Shadrach said:

I read the doc and I am not seeing the BMP. It says to lean at full throttle from full rich through peak RPM until the desired RPM is reached. It also says to avoid remaining at or above 75% for more than 15 secs (that’s an eternity to get past peak) at any setting other than full rich. As I read it, this process does not guarantee that the engine is lean of peak EGT; it guarantees that the engine is lean of peak power. 
 

I have always found the power charts for different NA engines curious. This POH says the engine won’t make 75% power above 6500’.

My POH say that my engine will make 77% power at 10,000’ on a warmer than standard day temperature.

That IS the BMP.

Fixed pitch versus Constant Speed prop.

[Danb]

On 1/6/2024 at 3:44 PM, BlueDun said:

Sorry for delay responding, @T. Peterson. Attached are settings from a recent flight at 13 gph LOP, 2400 RPM at 8,000 feet. That gave me 169/170 TAS. That same day I was 165 kt at 12.5 gph.

Specifically, I was wide open throttle on a high pressure day of 30.08 and it was 5 C colder than standard.

At 10,000' I am at 170 TAS or so with 12.5 gph. At 13 gph I am in low 170s.

Keep in mind that I have speed penalty of at least a couple knots because I have both air conditioning and FIKI. It was later not a factory option to get both.

Ovation 3, IO-500-N, 3-blade Hartzell, air conditioning, FIKi, G1000 WAAS.

 

 

 

BD what is that black leather case below the MFD where the a/p was?

[Shadrach]

1 hour ago, Pinecone said:

That IS the BMP.

Fixed pitch versus Constant Speed prop.

It’s semantics at this point. One man’s BMP is another's eternity in the red box. The document makes no mention of pulling as in depressing the button on the vernier and pulling the knob until deceleration. The genesis of this procedure was APS perhaps 25ish years ago. No one in 1982 would have interpreted that document in that way. It simply says lean past peak RPM to desired RPM. Do not operate the engine above 75% while leaning for more than 15 seconds. The instructions are pretty straightforward and easy to achieve without a BMP. 

[Shadrach]

On 12/29/2023 at 11:35 AM, Pinecone said:

The strange thing is, the pic I posted was from an ad for a 231.  But -LB and -GB show the 3 hole flute style.

I know the -MB and -SB have the one pictured is I have a 252.  And the only difference between those two are the RPM and MP red lines.

Just to close out this side bar. I’ve confirmed (I think) that LB and GB are three hole flutes… the Colorado accident 231 is an LB and has the 3 hole flute.

[Pinecone]

2 hours ago, Shadrach said:

It’s semantics at this point. One man’s BMP is another's eternity in the red box. The document makes no mention of pulling as in depressing the button on the vernier and pulling the knob until deceleration. The genesis of this procedure was APS perhaps 25ish years ago. No one in 1982 would have interpreted that document in that way. It simply says lean past peak RPM to desired RPM. Do not operate the engine above 75% while leaning for more than 15 seconds. The instructions are pretty straightforward and easy to achieve without a BMP. 

I would say leaning within 15 seconds is pretty much a BMP.

 

[BlueDun]

On 1/6/2024 at 9:09 PM, Jetpilot86 said:

When I did my insurance checkout for my Bravo in a G1000 Bravo, i just cringed at how much wasted space there was on that left PFD.  Admittedly, I'm used to a PFD/MFD combo right in front of me and just didn't like having to look "so far" over at that middle screen for NAV stuff.  Liked the G1000 best in Emergency Mode where I ended up with the PFD/NAV stuff right in front of me.  However, there a definitely a few things I don't have in my G600, that are on the G1000 I wish I did have...

I don't mind, but of course I am used to it. The small section in the lower left of the PFD -- where traffic is -- can be switched to a moving map with route. Yes., that's small but it can be done. I love the huge attitude indicator, horizon, HI, etc. Safe and easy to fly.

[BlueDun]

4 hours ago, Danb said:

BD what is that black leather case below the MFD where the a/p was?

This is an original factory-installed G1000 and GFC 700 installation, I believe, so perhaps the panel was legacy just prior to that configuration. Anyway, that flap velcros down to keep things from sliding out. Inside is a small quick guide to the G1000, a book in which I record VOR checks, and lense microfiber.

[Shadrach]

20 hours ago, Pinecone said:

I would say leaning within 15 seconds is pretty much a BMP.

 

Like I said, semantics. The BMP as it was taught to me nearly 20 years ago by one of APS’s instructors was as follows:

1) Pull (not twist) mixture control briskly to deceleration.

2) Enrich mixture to establish peak EGT from the lean side.

3) Lean to the desired mixture setting from peak. 

Apparently it means whatever people want it to mean as long as it occurs on the lean side.

To be clear, I don’t think the BMP is needed for an NA engine. I do lean that way, but do so because it’s faster, not because of the dreaded red box.

[PT20J]

When I took the course in 2007, the technique was just to pull the mixture back rather briskly until you felt a power drop and leave it there. Walter “demonstrated” it rather humorously by propelling himself across the room in an office  chair while mouthing engine noises. 

[Shadrach]

15 hours ago, PT20J said:

When I took the course in 2007, the technique was just to pull the mixture back rather briskly until you felt a power drop and leave it there. Walter “demonstrated” it rather humorously by propelling himself across the room in an office  chair while mouthing engine noises. 

That’s acceptable if you’re leaning to a target fuel flow and are equipped to do so.  It does not do much for leaning to a target mixture setting.

[T. Peterson]

On 1/6/2024 at 2:44 PM, BlueDun said:

Sorry for delay responding, @T. Peterson. Attached are settings from a recent flight at 13 gph LOP, 2400 RPM at 8,000 feet. That gave me 169/170 TAS. That same day I was 165 kt at 12.5 gph.

Specifically, I was wide open throttle on a high pressure day of 30.08 and it was 5 C colder than standard.

At 10,000' I am at 170 TAS or so with 12.5 gph. At 13 gph I am in low 170s.

Keep in mind that I have speed penalty of at least a couple knots because I have both air conditioning and FIKI. It was later not a factory option to get both.

Ovation 3, IO-500-N, 3-blade Hartzell, air conditioning, FIKi, G1000 WAAS.

 

 

 

Very nice!! Thanks for responding! I could have used anti-ice/de-ice today! Fortunately I was able to climb above it, but that sure would be a nice little feature to have in my back pocket!!