Rich of Peak (ROP) vs Lean of Peak (LOP)/Engine operation

[TGresham]

In making the decision to run ROP ("go fast") or LOP ("go far"), the discussion of fuel savings when running LOP tends to focus on saving money.

Two thoughts on that.

1. Some tend to minimize the savings as been inconsequencial. Well, each of us can decide whether a given dollar amount is important, but to do that, we need to know the dollar amount.

Assume (just grabbing numbers) a 1500-hour run on your engines. Assume, also, a 3 gph saving (using 1.5 gph per engine). That's pretty conservative, and I think it would be more than that. To make the math easy, let's use three bucks a gallon.

Saving $9 an hour for 1500 hours is $13,500. Now we have a number which each pilot/owner can use to decide whether it's important.

2. Much more important to me than the dollar savings is the safety,additional utility, and added speed which comes with extended range.

I seems that no matter what the aircraft is, running LOP in a general aviation plane adds at least an hour of range/time.

For planning, adding an hour of range opens more legal IFR alternates.

In the real world, I like getting to my destination knowing I have a lot of fuel, should the weather go down. I love having two or three hours of fuel I can use to get to better weather.

Speed. Extended range is the best speed mod. Eliminating a fuel stop is like picking up 25 knots. Sure, the true airspeed is lower (5 to 7 knots, usually) but if you can fly over the fuel stop, you avoid a delay of 30 minutes to an hour.

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