Because Owning And Flying Your Beechcraft Can Be Done Safely AND For Less Money!
  Green of Peak Engine Ops (formerly LOP) Saves Gas & Engines!

 

 

Confused about Lean of Peak (LOP) Operations?

 

The folks at Advanced Pilot Seminars can teach you more about why flying your engine "Green" of Peak is the best operating decision you can possibly make for the health of your engine!

 

The folks at Advanced Pilot Seminars even have an on-line course that you can purchase to get yourself educated on what's really happening in the internal combustion event. People say it's like "Myth Busters" for the operation of the piston aircraft engine!

 

Check out this LOP PowerPoint Presentation and this EGT Leaning Presentation created by Advanced Pilot Seminars for a good grounding in why this is the most efficient and effective operating technique for your air cooled horizontally opposed aircraft engine.

 

Check out the GAMI injectors page HERE

 

Check out this Engine Management Article written by Peter Holt

 

Below are pics of my spark plugs after 200 hours of Lean of Peak Operations. No self respecting CSOB wants to break or damage anything expensive and that's a big part of why I run my B55 Baron LOP. The folks running ROP are just kidding themselves and running their engines at the highest internal combustion pressures possible (and also the highest CHTs).

 

Removing the fuel past peak EGT does not melt cylinders, how the heck can removing the source of combustion energy do anything but remove the intensity of the fire! Your CHTs will be lower and that's a good thing for your cylinders.

 

Baron Owner and IA Stuart S. offers the following simplified explanation of LOP operations:

 

"The combustion event begins with the spark and the peak pressure occurs milliseconds later. LOP adds a bit of time to the event. The higher the RPM, the further past TDC that the peak internal combustion pressure occurs (ICP), resulting in less CHT."

 

This is another good reason to climb to your cruise altitude at maximum continuous RPM!

 

LOP is so easy a Caveman could do it <grins> See John Deakin's LOP guidance HERE

 

Here's the rough math on my LOP operations:

 

Give up ~3% of airspeed and receive about ~16% better range or fuel economy!

 

To me, that's a great deal. That's like getting 16 gallons of free fuel for every 100 gallons you burn! Or, on a massive headwind cross country trip not having to make that fuel stop. PLUS all the other advantages of lean and clean burning combustion operations inside your engine.

 

 

 

Here are pics of my Exhaust stacks after a 5 hour LOP flight from KATW to KDTO

 

                                            Left Engine IO-470L                                                                                      Right Engine IO-470L

 

Here is their infamous "Red Box" mixture vs. altitude diagram. Their recommendation is to avoid operations in the "Red Box". Note that above 8,000' the Red Box does not exist! You cannot hurt a normally aspirated engine with your mixture settings at altitudes above 8,000'.

 

Still confused? Click the link above for their seminar or on-line course.

 

Learn to use this KNOB!

 

The Dangerous Red Box

 

Just where is that "red box" John Deakin keeps talking about? Some rough numbers, good (that is to say, BAD) for most of these engines -- these are "no fly zones," DO NOT set the mixture between them:

 

Red Box = No Fly Zone

 

  • At and below about 60% power, there is no red box. Put the mixture wherever you want it.
  • At about 65% power or so, 100F ROP to Peak.
  • At about 70%, 125F ROP to 25F LOP.
  • At about 75%, 180F ROP to 40F LOP.
  • At about 80%, 200F ROP to 60F LOP.

 

All those numbers are approximate! Please don't start splitting hairs, here!

 

You probably don't want to run your engine between those mixture settings. If you do, you are running very high peak pressures inside the combustion chambers, and that peak pressure is occurring too close to top dead center.

 

There's a chance you read too fast, and missed this very important point, so let me put it another way:

 

Outside the Box

 

  • At 65% power, use richer than 100 ROP, or leaner than peak EGT.
  • At 70%, use richer than 125F ROP, or leaner than 25F LOP.
  • At 75%, use richer than 180F ROP, or leaner than 40F LOP.
  • At 80%, use richer than 200F ROP, or leaner than 60F LOP.

 

On most of these engines, with a properly set mixture at full rich, at sea level, full power, the EGT ends up at about 250F ROP, with some as high as 300F ROP and temps of 1250-1300F on most EGT monitoring equipment.

 

Lean of Peak Operation For IO-550   Lean of Peak Operation For IO-520
GPH HP GPH HP GPH HP GPH HP GPH HP GPH HP
10.0 50% 13.0 65% 16.0 79% 10.0 52% 13.0 68% 16.0 84%
10.2 51% 13.2 66% 16.2 80% 10.2 53% 13.2 69% 16.2 85%
10.4 52% 13.4 67% 16.4 81% 10.4 54% 13.4 70% 16.4 86%
10.6 53% 13.6 68% 16.6 82% 10.6 55% 13.6 71% 16.6 87%
10.8 54% 13.8 69% 16.8 83% 10.8 56% 13.8 72% 16.8 88%
11.0 55% 14.0 70% 17.0 84% 11.0 58% 14.0 73% 17.0 89%
11.2 56% 14.2 71% 17.2 85% 11.2 59% 14.2 74% 17.2 90%
11.4 57% 14.4 72% 17.4 86% 11.4 60% 14.4 75% 17.4 91%
11.6 58% 14.6 73% 17.6 87% 11.6 61% 14.6 76% 17.6 92%
11.8 59% 14.8 74% 17.8 88% 11.8 62% 14.8 77% 17.8 93%
12.0 60% 15.0 75% 18.0 89% 12.0 63% 15.0 78% 18.0 94%
12.2 61% 15.2 75% 18.2 90% 12.2 64% 15.2 79% 18.2 95%
12.4 62% 15.4 76% 18.4 91% 12.4 65% 15.4 81% 18.4 96%
12.6 63% 15.6 77% 18.6 92% 12.6 66% 15.6 82% 18.6 97%
12.8 64% 15.8 78% 18.8 93% 12.8 67% 15.8 83% 18.8 98%
 
Conversion Factor 14.9         Conversion Factor 14.9      
Max HP 300 Max HP 285
                         

 

ROP Percent Horsepower Chart
RPM
MP 2700 2600 2500 2400 2300 2200
29 100.0 97.5 95.0 92.5 90.0 87.5
28 96.5 94.0 91.5 89.0 86.5 84.0
27 93.0 90.5 88.0 85.5 83.0 80.5
26 89.5 87.0 84.5 82.0 79.5 77.0
25 86.0 83.5 81.0 78.5 76.0 73.5
24 82.5 80.0 77.5 75.0 72.5 70.0
23 79.0 76.5 74.0 71.5 69.0 66.5
22 75.5 73.0 70.5 68.0 65.5 63.0
21 72.0 69.5 67.0 64.5 62.0 59.5
20 68.5 66.0 63.5 61.0 58.5 56.0
           

 

Charts Courtesy of Beech Lister Elliott S.

 

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