Max Range and Tailwind
LN,
Perhaps a simple example will help:
Suppose your speed for Max Range (still air) is 100kts and at the required power setting you use 10gph and have an endurance of 5 hours (50gal). This would result in a still air range of 500nm.
Also suppose your aircraft burns 9.05gph at 90kts. Now you have an endurance of 5.52 hours - which gives a range of 497.24nm.
So, in still air, Max Range is achieved at 100kts.
Now add a tailwind of 12kts. All that changes, compared to the 2 examples above, is that the groundspeed changes. Hence:
90kts airspeed give range of 563.54nm (5.52 * 102).
100kts airspeed gives range of 560nm (5.00 * 112).
Basically you've had the benefit of the 12kts tailwind for an extra 31.5 minutes - taking you another 6.3nm for free. What you lose is that THROUGH THE AIR you do 9.95nm/g at 90kts as opposed to 10nm/g at 100kts.
Does that help?
OC619