Interesting: Gals/100 miles
 

Last night I was thinking about not GPH but MPG for a long trip ~1200 miles each way.
To come up with a good rule of thumb factor,

"What is the difference in time and gallons ...per 100 miles?"
Or per 1,000 miles?

I'm playing on PC to make some labels for my T337D
Just screwing around on a cool rainy day.

Don't worry, I haven't lost my mind, ...I don't think...

PWR MP RPM MAX MIN IAS 5K 10K 15K 20K ROP LOP GAL/100M MINS
75% 28 25 13.3 11.7 150 160 170 180 190 5.6 6.4 17.8 15.6 40
65% 26 24 12.2 10.3 140 150 160 170 180 5.75 6.75 17.3 14.8 43

The cols are organized as how I actually run engines.
Target %HP, then set MP, then RPM, then lean.

These are book figures, rounded for ease of use.
If book says 149 knots, I round to 150, etc.
Last 3 cols are ROP, LOP and mins to go 100k
The MAX / MIN (fuel) columns in middle are from TCM TSIO 360AB engine manual.
MAX is ROP and it would appear MIN seems to be = LOP.

===
Powering back from 75% to 65% reduces burn rate PER HOUR,
but it takes longer to get there, reducing the benefit a bit.

Therefore, to travel 100k miles the difference seems to be
75% ROP vs 65% LOP uses 3 gals more (17.8 vs 14.8) and gets there 3 mins faster

Over 1,000 miles,
75% ROP vs 65% LOP = 30 gals more and 30 mins earlier.
At $6/gal, that's $240 more fuel to arrive 30 mins faster, per 1,000 miles.


See, now I've got a nice shorthand!