ROP

[PT20J]

2 minutes ago, A64Pilot said:

If you could make as much power LOP as you can ROP, then why ever be  ROP? 

And, that's why LOP makes a lot of sense for turbos, and big engines (which can be effectively derated to use only a percentage of their capability). For M20Js with little normally aspirated Lycoming four bangers, LOP is relegated to corner cases: Low altitude in the flatlands, higher cruising altitudes when you are OK with Cherokee speeds but want great range and efficiency.

[Shadrach]

50 minutes ago, PT20J said:

It's a rare engine that will run well 100F LOP at any reasonable power. As you lean past about 50F, the cycle-to-cycle combustion variation becomes more pronounced as the mixture weakens and when you get too lean the engine runs rough and the power drops so much that the BSFC starts getting worse instead of better. Note that the BSFC curve in the Continental data bottoms out and then begins rising as the mixture is further weakened.

Mine will run reasonably at 100 but only at MP that is ludicrous in a NA airplane (low and cold). There is no utility in it. I only know because I was once experimenting with leaning until I got a second EGT rise.

 

1 hour ago, A64Pilot said:

The reason CHT isn’t linear on both sides of peak is because HP output isn’t linear, you lose much more HP per temp when LOP, that’s why we don’t often run 100 LOP, I can but power is so low I can’t stay in the air. CHT and power are pretty closely related until we get way outside of mixture, meaning for example full rich will cool you down significantly but lose only a bit of power

But you were right about both factory’s picking power settings that gave high power and high speeds. At normal cruise altitudes an NA airplane ROP is faster because you can’t make as much power LOP, and it’s my belief Lycoming didn’t want to publish cruise charts that had their engines not making good power

You’re really stuck on power loss thing with NA engines at altitude.

I was actually referring to CHT is on the Rich side of peak. Power from 300ROP to Peak is pretty flat,  CHTs in that pat of the spectrum is not linear. It’s a  shallow curve that bends increasingly upward as the mixture approaches 100° richest peak and then drops off again near peak

Also It would not be linear if you graphed a turbo engine at the same power level (and I mean power, not MP) through out the mixture spectrum. 

[Shadrach]

9 minutes ago, PT20J said:

And, that's why LOP makes a lot of sense for turbos, and big engines (which can be effectively derated to use only a percentage of their capability). For M20Js with little normally aspirated Lycoming four bangers, LOP is relegated to corner cases: Low altitude in the flatlands, higher cruising altitudes when you are OK with Cherokee speeds but want great range and efficiency.

Yup. I’m never LOP at altitude unless I’m enjoying 30kts on the tail. Max power LOP is for staying low and out of unfavorable winds.

[Ragsf15e]

1 hour ago, Shadrach said:

Yup. I’m never LOP at altitude unless I’m enjoying 30kts on the tail. Max power LOP is for staying low and out of unfavorable winds.

I had your “corner solution” LOP up high into a HW case today… long cross country, strong headwinds, Spokane, WA to Carson City, NV which gives not many places for a stop, high terrain gives 9,500’ or 10,500 as your only choices (or higher).  Loaded close enough to max gw for me gave 56 gallons of fuel.  Ran just barely LOP (pretty much peak) at about 138ktas which gave me ~118kts ground.  I landed with 15 gallons after 4.7 hobbs (including ground time).  I would have preferred faster, but then i Would have had to stop in Burns, OR if I was ROP.

[PT20J]

34 minutes ago, Ragsf15e said:

I had your “corner solution” LOP up high into a HW case today… long cross country, strong headwinds, Spokane, WA to Carson City, NV which gives not many places for a stop, high terrain gives 9,500’ or 10,500 as your only choices (or higher).  Loaded close enough to max gw for me gave 56 gallons of fuel.  Ran just barely LOP (pretty much peak) at about 138ktas which gave me ~118kts ground.  I landed with 15 gallons after 4.7 hobbs (including ground time).  I would have preferred faster, but then i Would have had to stop in Burns, OR if I was ROP.

I've been to Burns. Good decision. Always good to have options (and know how to use them!) 

[Shadrach]

9 hours ago, Ragsf15e said:

I had your “corner solution” LOP up high into a HW case today… long cross country, strong headwinds, Spokane, WA to Carson City, NV which gives not many places for a stop, high terrain gives 9,500’ or 10,500 as your only choices (or higher).  Loaded close enough to max gw for me gave 56 gallons of fuel.  Ran just barely LOP (pretty much peak) at about 138ktas which gave me ~118kts ground.  I landed with 15 gallons after 4.7 hobbs (including ground time).  I would have preferred faster, but then i Would have had to stop in Burns, OR if I was ROP.

Peak on the richest cylinder is my preferred setting at mid altitudes. Then best power in the teens.

[A64Pilot]

I’m stuck on the loss of power LOP because it’s real, and playing LOP games while trying to make higher power is how you can hurt your motor.

People hurt their motor that way by not running lean enough, they don’t run lean enough because of power drop off, so they try some more dangerous setting like 10 LOP, dangerous only at higher MP, it and any mixture is safe at low power

10 LOP is fine so long as your not trying to make high power. Too many times I’ve read “simply increase MP to recover any lost power” without any mention of how much to simply increase. To me teaching that is not in the best interest of the pilot, now if it said simply increase MP to recover power, but ensure you stay below xx% percent, then that would be in the best interest of the pilot

But you right, LOP is pretty much for down low and is best for lower power ops. Follow those guide lines and you won’t hurt anything

But that’s not what you usually read.

That 210 I talk about, it got a new factory motor after my Brother detonated it to death trying to keep up with me when I was delivering a -60 powered crop duster. He called me and told me he could feel the landing gear thumping the bottom of the airplane. Apparently detonation in a IO-520 feels like the gear do when the come fully up in a C-210. We were maybe 2000 ft and he was wide open and of course too lean. If I had thought to tell him to go to full rich, we may have saved that motor, but I was stuck on landing gear, because 210’s have gear problems.

We landed, I finished the delivery, he called one of our dealers who flew out thinking it was a plug or injector whatever, but it was a holed piston.

So I flew back in the back seat of an A-36, that’s when I decided I didn’t want any kind of Bonanza as I fought airsickness all the way home.

[Cruiser]

20 hours ago, PT20J said:

I don't think it's quite that dramatic for a real engine. Below is a curve from a 1990 Continental Maintenance and Operator's Manual for an IO-550G. The document does not specify how the data was obtained, but it is a good bet that it was in a test cell with calibrated instrumentation using a test club and very good cooling airflow. .... snip

 

Skip

My IO-550G CHT never approached 420+ °F in real world operation, (except for the #5 cylinder cooling issue behind the alternator)

[PT20J]

2 hours ago, A64Pilot said:

10 LOP is fine so long as your not trying to make high power. Too many times I’ve read “simply increase MP to recover any lost power” without any mention of how much to simply increase. To me teaching that is not in the best interest of the pilot, now if it said simply increase MP to recover power, but ensure you stay below xx% percent, then that would be in the best interest of the pilot

This is a case where a little knowledge can lead one astray. Anyone wishing to run LOP at high power needs to understand the red box concept. It's thoroughly covered in the APS course and has been written about extensively by Mike Busch and others.

As your brother discovered, some engines are easily damaged by mixture mismanagement.  My only gripe with the red box is that, in the form usually presented, it is based on engines most likely to have issues and is overly conservative for many engines. It can also lead those with incomplete understanding to conclude that any mixture near peak EGT is universally bad for any engine. But, at least by following the oft-published recommendations you won't hurt anything.

Skip

[A64Pilot]

My biggest gripe is that you must have all this equipment to run LOP, starting with Gami Injectors, I’ve had two sets, one on the new 520 and a second on the 540 I overhauled, made pretty much no difference in either case, the 540 just wouldn’t run LOP well, that motor just wasn’t an LOP candidate, perhaps as the 520 was a new factory motor probably 10 to 12 years ago maybe Conti was supplying matched injectors by then. Both engines fine wires made more of a difference.

Now my 360 is a Gann Performance motor that he balances to within 1 gram, pretty sure he polishes ports and may even flow match on a flow bench, I’ve never been to his shop, but I’d flow match, flow bench’s just aren’t that expensive, normal motor I CC’d head too, but don’t see how you could an aircraft motor as the head isn’t normally removable.

But it will continue to run smooth down to the point to where you can’t maintain 100 kts, with Lycoming injectors and massive plugs.

My Brother wasn’t trying LOP. he was apparently using numbers he had been taught, I’m sure he had been taught fly at xx fuel flow by a CFI who knew nothing about motors. He just didn’t know that if your going to fly wide open down low, better be full rich. I had to be at high power to make it to Arkansas on one tank, turbines are most efficient at high power, sort of the opposite of a piston. When I bought my Mooney, it was from a Private pilot. I asked how he leaned it, if he ran ROP or LOP, he was a little confused, his answer was he ran it between 725 and 750 EGT. Nice guy, but he really shouldn’t have been in a complex aircraft, he was selling the J to buy something with airconditioning, probably a Cirrus. If he had done like my Brother he might have detonated the Lycoming to death too. Because he flew full rich below 5,000 and leaned at cruise to safe ROP numbers he didn’t hurt anything and didn’t have to know what he was doing, He wanted to go fast anyway, if my Brother had done the full rich below 5,000 he would have saved about $ 50K

But you certainly can hurt an engine with mixture, if your at high power 

[PT20J]

Interesting thing I recently learned about Lycoming injectors from Al Jesmer at Precision Airmotive. Most of us know that the RSA injectors have a body with a flow restrictor insert. The body has a precision drilled hole and the bore of the insert is also a precision drilled part. The manual describes these parts as "matched" and you're not supposed to mix them up.

The only test that Precision does is to run calibration fluid at a specific pressure through each combination of body and insert and observe that the fluid comes out is a steady stream about the diameter of a #2 pencil lead. Sometimes due to manufacturing tolerances, the holes are not perfectly aligned and the injector doesn't produce a good stream in which case they swap parts around until they work right. That's it. 

So, if you ever somehow mix up parts, you can just test the injectors by connecting them to the fuel lines and running the boost pump and swap parts until you get good streams.

Skip

[carusoam]

For fun….

Lean your engine as deep as possible….

To define where peak really is…. And if your EGT sensors are fast enough to record it, at the rate you are leaning…. You may need to slow down for accuracy…

Some sensors are quicker than others… others are more durable…. 

My IO550(g) was able to get about 90°F LOP near 5k’ altitude before gently shutting off… no roughness encountered… Gami spread close to zero…

To go 100°F LOP (thanks Ross) cold and lower altitude may need to be required…

at 12k’ it could go 50°F LOP before shutting off…

Going deeper LOP than peak at less than 65%bhp…. Is only a CHT challenge….

The Ovation has amazing CHT control… with only the hard to avoid CHT#5, resident behind the alternator…

Since our cooling for the IO550 is top to bottom flow… why does the alternator cause cooling issues for cylinder #5… and not #s 3&1?   
 

If the horizontal flow into the cowl is important….

Why isn’t cylinder #6 (no alternator present) running cooler than the rest?
 

and #s 1&2 not the highest CHTs…?

(note Continental cylinder numbers are highest at the front…. #6 is pilot side front… Lycoming #s run the other direction)

 

The key to having an engine that is so well balanced…. Get lucky by buying the plane from the right previous owner….  Some pilots really enjoy their engine technology 

 

Getting a Gami spread near zero is possible… but probably takes a bunch of extra effort…

 

Running deep LOP, with high power, at altitudes…. Requires twin snails….  Go Acclaim!

 

Knowing your engine really well…. It is possible to use FF to know where PEAK is generally…

I like to know where peak is exactly…. A few degrees LOP is enough to know all of the 100LL is being converted to loud noise…. None is escaping as used cooling fluid….  
 

Maximum speed, maximum fuel used for power, 2550rpm for the TopProp…. 

Fun times…

-a-

[A64Pilot]

I can easily get deep enough LOP so that the EGT actually starts increasing again and this confuses me somewhat. If the flame front propagation is so slow that the burn isn’t complete before exhaust stroke begins, you shouldn’t be able to ignite a charge that lean, not without a stratified charge combustion chamber which we certainly are not.

[Shadrach]

7 hours ago, A64Pilot said:

My biggest gripe is that you must have all this equipment to run LOP, starting with Gami Injectors, I’ve had two sets, one on the new 520 and a second on the 540 I overhauled, made pretty much no difference in either case, the 540 just wouldn’t run LOP well, that motor just wasn’t an LOP candidate, perhaps as the 520 was a new factory motor probably 10 to 12 years ago maybe Conti was supplying matched injectors by then. Both engines fine wires made more of a difference.

Now my 360 is a Gann Performance motor that he balances to within 1 gram, pretty sure he polishes ports and may even flow match on a flow bench, I’ve never been to his shop, but I’d flow match, flow bench’s just aren’t that expensive, normal motor I CC’d head too, but don’t see how you could an aircraft motor as the head isn’t normally removable.

But it will continue to run smooth down to the point to where you can’t maintain 100 kts, with Lycoming injectors and massive plugs.

My Brother wasn’t trying LOP. he was apparently using numbers he had been taught, I’m sure he had been taught fly at xx fuel flow by a CFI who knew nothing about motors. He just didn’t know that if your going to fly wide open down low, better be full rich. I had to be at high power to make it to Arkansas on one tank, turbines are most efficient at high power, sort of the opposite of a piston. When I bought my Mooney, it was from a Private pilot. I asked how he leaned it, if he ran ROP or LOP, he was a little confused, his answer was he ran it between 725 and 750 EGT. Nice guy, but he really shouldn’t have been in a complex aircraft, he was selling the J to buy something with airconditioning, probably a Cirrus. If he had done like my Brother he might have detonated the Lycoming to death too. Because he flew full rich below 5,000 and leaned at cruise to safe ROP numbers he didn’t hurt anything and didn’t have to know what he was doing, He wanted to go fast anyway, if my Brother had done the full rich below 5,000 he would have saved about $ 50K

But you certainly can hurt an engine with mixture, if your at high power 

This thread is exhausting. I have tried in good faith to address the misconceptions and misunderstandings in your posts.  I took the time to literally dissect a post sentence by sentence and provide the most concise answers I could. You ignored it all.  Many of the people in this thread have decades of observing how these engines respond in real time under various operating conditions and power settings. Yet you who think engine monitors are overrated, dane to explain to he rest of us that we are playing LOP or ROP or whatever “games”.  It seems like you learned learned everything you wanted to at some time in the past and want to tell everyone who doesn’t share you views to get off your lawn. Fair enough. This thread is a bloody pulp of a dead horse that should be buried. You seem to have a very interesting aviation background and a tremendous amount of knowledge. That’s something that is valued around here. I find your stories and anecdotes about the military, test piloting Maules et al…very interesting and I look forward to more of it. However, with regard to this thread, it seems obvious that you’re here to set everyone straight not actually learn anything, at least not from the likes of me.  I’m stubborn but I’ve got the message. I’m out.  Enjoy the weekend. 

[A64Pilot]

You and I go back and forth on this, What I’m trying to do is keep those who read an article or two from the experts that are often shot full of errors and go out there and think they can fly at the same speed they have been, just save 20% of fuel, and end up with a $50K engine replacement bill. I’ve seen it quite often.

As I have said before, Mooneyspace is a microcosm, but we have two current threads running about detonated cylinders, and often detonation damage is much more than just cylinders, it shows up later as bearing wear, possibly broken rods, cracked cases etc. It does happen, and just about every case of it is from running high power leaned out, I’ve seen several cases and from what I’ve seen that was the cause in every case. Oddly I’ve not seen one from a clogged injector, every injector clogging I have experience with it clogged enough to put the cylinder too lean to detonate

There is a whole lot of marketing with injectors and ignitions etc that basically say buy our product and you will save bunches of money on fuel, but in truth any fuel savings is marginal at best.

Then you have an article written by a Naval test pilot school grad, an honest REAL professional, who really knows how to both write and fly a test plan and you discard his findings, because you dislike them, he’s not in line with the combustion scientist who are marketing their products.

Basically he said what Lycoming said, that yes there is a fuel saving to be had, but not as much as is what’s advertised and the potential for serious damage exists. 

So far as errors I won’t go through the article that was quoted and argue as I’m no self proclaimed “combustion scientist” But even I know that pistons don’t melt below 1,000 F not even close

You just can’t tell the converts anything, the Lycoming letter from years ago was actually spot on, al, they were trying to get people to understand that there is significant possibility for damage, but all the converts stood up in support of the “combustion scientists” decrying Lycoming as fools, so they just gave up.

So what I’m trying to do is to try to get people who are waffling on fancy props, fancy ignition systems, fancy injectors and the “new” way of operating an engine to really try to find out how much performance increase or how much honest fuel saving there is. Hint, it’s not as much as advertised, take the speed mods for instance, if you add up the speed increases advertised it’s a big number, one that will be unrealized in real life.

Even VG’s , I know Anni Brogan really well, nice person, she’s a successful businesswoman, but VG’s aren’t for every airplane, and if you put an airspeed boom on an airplane and really go out and test, you won’t get advertised numbers, but people who spent that money you can’t convince, it’s human nature.

I had never though about it until I talked to Hartzell’s Engineers about a variable timing electronic ignition and they sat me down and quickly explained about how changing ignition timing will change the torsional vibration and when they did the vibe surveys for the prop they did not survey any change in timing. That torsional vibration could do anything from wreck hubs to cause crankshaft cracks to who knows, or it may be inconsequential.  if you want to go that route you may want to consider an MT prop

I’m not trying to convince you of anything, I know that’s not happening, but what I try to do is be the voice of reason for those tempted by the advertising and all the converts on the internet to give a hard thought of if there is anything really wrong with their airplane as Mooney manufactured it, does it really need “improving” and if the thousands they will spend on whatever mod is really worth it, or would they be happier flying hundreds of hours more with that money instead.

Now some have the income where it doesn’t matter they enjoy spending their money on the latest greatest piece of must have whatever and it’s their money so it’s fine, but most don’t average owner of an older GA airplane has a budget, often it’s why so many tie down.

‘I don’t say that engine monitors are overrated, that’s what you want to hear. What I do say it that contrary to what you hear from the experts they are not necessary to run LOP safely.

Too many people who read the articles are convinced to run LOP believe they have to first spend thousands on an engine monitor where they do NOT, you can safely run LOP or any other mixture if you do so at less than 65% power, so if you want a monitor buy one, but you don’t have to have it.

Edited May 29, 2022 by A64Pilot

[McMooney]

man, just ran across this on lycomings site, who would've guessed that instructor guy knew what he was talking about

 

Leaning Lycoming Engines | lycoming.com

 

Edited May 29, 2022 by McMooney
site submits deleted text

[McMooney]

20 hours ago, McMooney said:

man, just ran across this on lycomings site, who would've guessed that instructor guy knew what he was talking about

 

Leaning Lycoming Engines | lycoming.com

 

I noticed after reading the actual bulletin, following published leaning proc, I'd be pretty far LOP.

 

[PT20J]

I was curious about the assertion that most of the economy running LOP is from reduction in horsepower. Certainly if you use the Lycoming and Continental approved method of setting power ROP before leaning and not changing MAP or rpm there is a power loss. Using the charts from Continental's 1990 manual for a 280 hp IO-550G, the power drop of from best power mixture to lowest BSFC mixture is about 5%. 

Within the family of curves I found a curve that shows best power about 215 bhp (~75%) and another curve that shows best economy at the same 215 bhp. In the first case the BSFC is 0.42 or 15.1 gph. In the second case, the BSFC is 0.38 or 13.6 gph. So, according to Continental, the savings is 1.5 gph going from best power to best economy at the same brake horsepower.

Skip

[A64Pilot]

However best power is just exactly that, and is usually far richer than normal cruise. best power is normally only used for speed over fuel consumption and you can’t make that HP LOP, unless your running best power at reduced throttle, which is nonsensical. If you want to really make the LOP case, use full rich. Not being argumentative, but you should use logical cruise mixture settings to compare.

Lycoming as an example recommends or on the 540 did 50 ROP for normal cruise and peak for economy cruise. Lycoming in there somewhere also recommends max cruise power at 75%, anything above 75% full rich, but you can’t make above 75% at what most consider normal cruise altitude anyway.

So go back and with the chart rerun the numbers not at best power but from peak or even 50 ROP.

‘From the beginning of this I said most like to compare LOP to best power to illustrate fuel savings.

Its not hard really, climb to cruise altitude, pick your RPM and WOT, then run around 40 LOP, if that gives you a speed you can live with then that’s going to be within smidgens of best MPG, if it’s too slow, enrichen.

This assumes cruise altitude and RPM to be below 75% for a Lycoming of course and a non turbo.

Finally the Conti 500 is a slightly different motor, some of them have a BSFC that a Lycoming just can’t achieve, and due I assume to combustion chamber design, maybe better swirl can run better LOP than a Lycoming, but I believe have to be at a lower power setting 65% for it not to be possible to detonate

 

[PT20J]

According to the graphs, best power on the IO-550G is about 50F ROP and min BSFC is about 50F LOP. All I'm claiming is that on this engine, according to the manufacturer's published data, at 75% power the largest spread between the richest mixture that makes sense and the leanest is 1.5 gph. You can pick any two points that you might prefer that are closer together and you will necessarily get less spread.

Skip

[A64Pilot]

1 hour ago, PT20J said:

According to the graphs, best power on the IO-550G is about 50F ROP and min BSFC is about 50F LOP. All I'm claiming is that on this engine, according to the manufacturer's published data, at 75% power the largest spread between the richest mixture that makes sense and the leanest is 1.5 gph. You can pick any two points that you might prefer that are closer together and you will necessarily get less spread.

Skip

That’s an issue, I keep talking Lycoming and they while being very similar are pretty different engines than Continental’s big motors. Ford and Chevrolet both make V8’s but they are different, I maintain Ford has never held a card to the Chevy small block, but then I’m a GM fan. FORD did rule back in the flat head days though, but I’m not that old.

But even within Lycomings there are significant differences, on the surface it looks like the 360 is just missing two of the 540’s cylinders, but they sure operate differently, my Parallel valve 540 just would not run LOP, I assume the angle valve has much more swirl / turbulence, in fact I’m sure of it.

Just listen to a big Conti idle, even the 0-470’s sound like drag motors they way they lope. There is way “more” cam to a Conti, be interesting to know the timing, valve overlap and duration for both motors. One day if I get real bored I’ll get out my degree wheel and dial indicator and see.

Which had always confused me as to why are Lycomings the race motor? I guess factory support?

But in any motor, there will be for a given MP and RPM just one mixture setting that will obtain the best BSFC, and it will be almost certainly LOP, as there will be only one mixture that will give best power and it will be ROP, but there is no mixture that gives both.

There is a little more to it than that though, lower RPM will reduce engine friction, and lower prop speeds are slightly more efficient and WOT will reduce pumping losses as low as possible and those three add up to a little less fuel burn, not huge but a little, a little here and there adds up. Heck the Challenger air filter advertises both a HP increase and up to a half gallon an hour decrease in fuel consumption, let me write that check  That’s a savings of over $3 an hour and increased power, over a 2,000 hour TBO that’s over $6,000 from just an air filter. ( tongue in cheek, I don’t really believe it, but it’s what they advertise)

Oh and it’s Green too, wonder how with that oil?

https://www.challengeraviation.com

From other aircraft and I think my Mooney too the sweet spot is 7,000 give or take 500’, that gives me right at 22”MP WOT, my motor is smooth at 2200 and run just 25 or so LOP (factory single probe EGT). If I climb she may slow down so I either accept that or enrichen to maintain power, if I descend I keep it at 22 MP so I can’t hurt anything.

‘N/A motors only

Edited May 31, 2022 by A64Pilot

[A64Pilot]

51 minutes ago, PT20J said:

According to the graphs, best power on the IO-550G is about 50F ROP and min BSFC is about 50F LOP. All I'm claiming is that on this engine, according to the manufacturer's published data, at 75% power the largest spread between the richest mixture that makes sense and the leanest is 1.5 gph. You can pick any two points that you might prefer that are closer together and you will necessarily get less spread.

Skip

OK I think I understand, your point is the largest is 1.5 but less is likely? I apologize I read it as run LOP and save 1.5 GPH an hour giving up nothing, which is what I hear so often. Of course it should be noted that in your example the throttle is more closed at ROP than LOP

There simply just ain’t no such thing as a free lunch

[Gatlin Gun]

I can’t wait for the potential backlash from my rocket/missile brothers, but when I bought my Rocket and asked about the CFIs input about flying LOP, he said something like “Dude, you’re buying a rocket…if you’re looking for LOP, you’re buying the wrong plane”.

[T. Peterson]

On 5/27/2022 at 8:27 AM, Fly Boomer said:

Don't know if you like to read sometimes tedious technical stuff, but this Mike Busch article is the best condensation of the APS course (If that's even possible) I can think of.

Savvy Aviator 59 - EGT, CHT, and Leaning.pdf 105.02 kB · 23 downloads

I finally got around to reading this and it makes so much sense!!

 Thank you for posting it!!

Torrey

[Little Dipper]

Gez.....  A weeks worth of reading on a single thread.    Sounds like every one is playing with their JPIs and worrying about their engine instead of looking out the window.   What ever happened to the old days when we leaned the mixture till the engine started to run rough then gave the mixture control a quarter turn in then forget about it?