Here's my question. I fly stock F550. At first I used a 3S 5200Mah 45C lipo and was getting about 7 1/2 minutes flight time. I purchased a 4S 5000Mah 50C lipo and got over 15 minutes flight time. During the last flight with the 5000Mah lipo, I notice that as the lipo voltages dropped, it seemed...