Plane & Pilot
Saturday, May 1, 2004

An Advanced Course In Engine Management

When you have to pay for fuel, repairs and overhauls, you’ll want to treat your powerplant to the values of science, not hearsay

Today, bookstores have shelves of self-help and how-to books targeted at people just like me. You know, books like Brain Surgery For Dummies, Taxes For Dummies or The Idiot’s Guide To Juggling. There is one guide, however, that you won’t find in your local bookstore or, unfortunately, at your local airport. The Advanced Pilot Seminar (APS), better than books like Engine Management For Dummies, can only be found in Ada, Okla.
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Lean mixtures also delay the peak cylinder pressures, delaying the maximum power pulse until well after TDC. The increased mechanical advantage of the connecting rod mitigates the power loss, but it’s a fact of life that power drops off faster at leaner mixtures. As a matter of fact, you experience this effect every time you shut down your engine by leaning until fuel starvation.

What about rpm? How about lean misfire? How do I know what my ICP is? Should I install an engine monitor? Won’t I burn my valves? What about deposits in the cylinder and on the piston? What is detonation and how can I avoid it? What does the temperature range of a spark plug mean to operation? Why do you say that I can run lean of peak if my engine shop or mechanic warn me about running too lean?

Lots of questions and lots of good reasons to attend the Advanced Pilot Seminar for pilots and mechanics. Attendance counts toward the FAA Wings program and the continuing education requirement for IAs. The bottom line is, if I told you all of their secrets, they’d kill me. But I’ll give you a hint, one simple, important lesson from the test stand.

Real test-stand results show that similar internal cylinder pressures are reached at 120 degrees rich of peak and at 30 degrees lean of peak. Anything between these values is an area where internal cylinder pressures are too high and, in some engines, dangerously high. Essentially, this red box gets bigger at higher power settings, it’s an operating area where fuel-per-air mixtures can do real damage to your engine.

So your mechanic is partly right, but for the wrong reasons. The real problem is not lean operations, but that we’re not running rich enough. If you can’t answer one basic question, based on fact, this course is for you. So, where do you run your engine?

If you want to know more or see the future through PRISM, call APS at (225) 925-2066 or reach them on the Web at

Labels: FinanceMaintenance


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