OK SO HERE IS THE PROBLEM: People do not know what is the best altitude to fly their airplane for maximum gas mileage, and even if they think they know from experience, they have no idea what to do once you throw varying WIND into the equation... they might say something vague and over-generalized like "My plane flies best at 8,000 feet, and if there is a headwind I go lower."

NOT TOO SMART!

Here is why:

Take the 2003 Cirrus SR-22 for example:
At 2,000 feet, 72% power gives us 167 knots on 17.0 gallons per hour. (rich of peak mixture)
At 17,000 feet, 50% power gives us 167 knots on 10.5 gallons per hour. (lean of peak mixture)

But wait! WHY DID I RUN LEAN OF PEAK UP HIGH, BUT NOT DOWN LOW? Because At only 50% power, we can run lean of peak WITH NO POSSIBLE CHANCE OF ENGINE DAMAGE because of the low power output of the engine. At HIGH power settings, though, we couls easily destroy the engine if we run too close to peak EGT.

So, we run LEAN OF PEAK at LOW power settings, and RICH OF PEAK at HIGH power settings.

So, running below about 2/3 power has a triple-benefit... it is easier on the engine, burns less fuel, and lets you run lean of peak with no chance of engine damage... something you might not do at high power!

So, at 17,000 feet versus 2,000 feet, we burn 10.5 gph versus 17.0 gph for the SAME AIRSPEED.

Clearly, we should fly high.

But, what if there is a headwind up high? Most pilots will fly low.. but wait! HOW MUCH HEADWIND UP HIGH IS ENOUGH HEADWIND TO FORCE US TO FLY LOW, WHERE OUR EFFICIENCY IS TERRIBLE?

And what about the clumb? Is it WORTH the fuel spent in climb to climb way up high?

Finally, you can get all the answers.

Download AltitudeOptimizer, enter the altitudes, speeds, and fuel-flows for YOUR airplane, right out of the operating handbook.

Then, before you fly, enter the winds at various altitudes that the briefer gave you... AltitudeOptimizer will give you the groundspeed and gas mileage for each altitude... and tell you what altitude gives the best speed/efficiency combination!

USE THIS PROGRAM! IT IS FREE AND WILL SAVE YOU GAS!
FINALLY, NO MORE GUESSING ABOUT WHAT ALTITUDE WILL GIVE THE BEST RESULT IN A HEADWIND OR TAILWIND!

YOU MUST DROP THIS APP INTO YOUR X-PLANE-9 FOLDER FOR IT TO WORK!

Download here for Mac: AltitudeOptimizer 9.00 (free)
Download here for Windows: AltitudeOptimizer 9.00 (free)