AOPA Turbine Pilot Magazine - July 2011 - 22

LETTERS

Dogfight: Running Lean of Peak
turer’s suggested procedure? And that, sirs, is not LOP . Larry Harmacinski, AOPA 1336476 Cornelius, North Carolina I am writing because I’m a fan of rich of peak operations, but not for the reasons Tom Horne discusses. I own and operate a 1979 Mooney 231 M20K (no GAMIs). Early this year, I installed an Insight G3 monitor. It’s been well worth the wait and the investment. Simple to use, the G3 is intuitive to find both ROP and LOP settings. I’m a retired Army Cobra pilot, so simple is always a good thing. Here’s what I found. I ran the airplane on a series of flights comparing ROP and LOP differences in fuel flow, TAS, miles per gallon, percentage horsepower, ETE, and fuel range. I routinely operate in the 12,000- to 17,000-foot altitude range between south Alabama and the Washington, D.C., area. My results for a 12,000 cruise altitude, 2,500 rpm, 72 gallons usable fuel were very interesting. While I was getting better fuel flow and better mpg, when taken into context of time flown on a long trip, I did not gain any appreciative distance—max range only increases 60 statute miles. However, the time to get there was an extra hour of flight time. The extra flight time translates into more money spent on TBO items (engine, prop, service) that far exceeded the 12 gallons of fuel saved per hour for the same distance flown. At the end of a 1,000-mile flight, I will still spend the same amount of money in fuel; I will only do so one hour later because of the slower resulting TAS. So, if I’m just putzing around the local area, I’ll run slow and LOP (55 percent horsepower) because I’m just out enjoying the sights. However, if I’ve got somewhere to be, ROP is for me. Tim Rhyne, AOPA 1787684 Enterprise, Alabama

am certain that lean of peak operations have a place, but that place resides in GAMI or similarly equipped aircraft, and I would be surprised if that number

is as high as your writers indicate (“Dogfight: Running Lean of Peak,” May 2011 AOPA Pilot). Most of my time is with the airlines, but I do fly my 1932 Waco on days off and fly my friend’s Bonanza and 140 as well. LOP has no place with normal (read “older”) fuel systems. LOP is not a widespread policy as Dave Hirschman seems to suggest, but rather applies to certain engines, and only certain aircraft installations. To back up Tom Horne’s viewpoint, call G&N Aircraft, one of the most highly regarded shops in the United States— they advise against LOP operations. Lastly, I really am not a fan of the ongoing debate-style commentary; there never is a definitive resolution, although that is innate in much of aviation. Could I suggest that for the sake of the weekend pilot’s engine health, that people with carbureted engines be told to follow the manufac-

An old salt once told me: “You can cool your cylinders with fuel, or you can cool ’em with air. Most folks understand that air is much cheaper.” As long as the proper instrumentation is installed, or the engine is round, lean of peak is a piece of cake. Most folks know that carb-equipped flat motors are generally not capable of LOP operations; those that don’t probably spend money on valves. Mark Frederick, AOPA 0909468 Taylor, Texas
AOPA PILOT •

22 • JULY 2011

AOPA Turbine Pilot Magazine - July 2011

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