[n86121]

Last Sunday was cold and rainy, so I started compiling various engine and airframe performance charts into something useful.

While there are billions and billions of tables, does anyone really fly using them?

I think in reality we

1) set manifold pressure, then
2) RPM, then
3) lean, ...and away we go!

Beyond that is just obsessive diddling with things

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One 'constant' is INDICATED airspeed at SEA LEVEL for a given power setting.

From that INDICATED airspeed one can then use math to determine TRUE airspeed, adjust for pressure altitude, temperature etc. But we can only adjust power for a shown IAS.

The TCM engine manual has tables for rich to lean, for example.

The table below shows the limits from the TCM engine manual for my TSIO 360ABs

QUESTION #1: With GAMI do you lean BELOW the 'lean' values in the TCM manual? or...

QUESTION #2: With GAMI do you just run smoothly at the SAME TCM lean settings?



Below is the user table I derived from the various tables and manuals.

Next time I have time to spare I will flight check reality vs tables.

The efficiency values to right are MPG and speed, vs baseline of 75% at ROP.

For example, running the engine 75% power LOP would get you 20% better MPG than ROP with no loss in speed. Running 65% power LOP is 24% better MPG, with a loss in speed of 7%, etc.

Comments? Comparisons?

SET IAS @ altitude GAL/HR KNOTS/GAL LOP LOP
MP RPM PWR MPH KTS 5k 10k 15k ROP MID LOP ROP GPH LOP +EFF -SPD
32 28 100% 178 155 - - - 42 40 ---
28 25 75% 173 150 160 169 177 28 24 23 5.4 6.3 6.5 20% ---
24 70% 169 147 156 165 175 26 23 22 5.7 6.4 6.7 24% 2%
26 26 70% 169 147 156 165 175 26 23 22 5.7 6.4 6.7 24% 2%
24 65% 161 140 150 159 169 24 23 21 5.8 6.1 6.7 24% 7%
22 55% 151 131 143 152 162 21 19 18 6.2 6.9 7.3 35% 13%
24 22 50% 143 124 135 144 155 18 17 16 6.9 7.3 7.8 44% 17%