Is there a ballpark number that represents the percentage of static launch power that the motor draws in the air when it unloads.  Basically if I launch at 220watts what can I expect that to drop off to in the air?  I know there are many variables in this equation, prop diameter and pitch, motor kv, even air density.  I am hoping that somebody has a general number that can be used.  I guess this is the kind of data that can be downloaded from the high end CC ESC's. 
Andy

Great input!  Andy and I are trying to get a handle on this from the standpoint of helping Eric Rule develop a number of different power level systems.  Currently, we are working on a system to power what would be a "wet" .15 size model.  350sq.in., 52' x .012 lines.  Since we want a lowest cost package, we need to learn how to understand the variables and select the hardware appropriately.  At present we have a nominal 220 watt motor of 1100 kv. and are fiddeling around with props trying to get it to drain 1760 mAH from a 2200mAh battery while being able to fly the pattern in about 5.5 minutes.  It looks like the APC 9x6 e prop may be the trick, though it may need to be trimmed to get the drain perfect over the flight time.  The 8x6 didn't pull the freight and left a lot of milliamp-hours on the table.  A 9x4.75 prop cut down to 8.5" seemed to work ok, but not exactly available in the local 7-11.

Since we are newbies to this, we may be off the mark on what kv motor and prop to use.  The drain and battery figures are from theory, and seem to be working out.  We are very close to a satisfactory system, but, being the bright lads we are, would love to understand the theory better.

It looks like the APC 9x6 e prop may be the trick, though it may need to be trimmed to get the drain perfect over the flight time.  The 8x6 didn't pull the freight and left a lot of milliamp-hours on the table.  A 9x4.75 prop cut down to 8.5" seemed to work ok, but not exactly available in the local 7-11.

Have you experimented with the speed setting on the timer or governor?  Turning the speed down should have some of the same effect as de-pitching the prop, and should be easier than hacking the thing down.

Yes, I was suggesting that you use the 9x6 prop, and turn down the governor RPM to get the lap times/current draw you want.