ORIGINAL: NJRCFLYER2
3A average per flight? You've got a real problem if that's really the case! You shouldn't be exceeding 1Ah average for the entire flight (assumed a 15 minute, energetic 3D flight). This, based on actual readings from flying a 40% Carden Extra with 8 digitals (600 mAh avg) and extrapolating to your 11 servo setup. Better check for some serious binding or mis-adjustment in yout servo centering/endpoint/tracking linearity with any ganged servos.
No, the AVERAGE LOAD is 3 amps at any given time during the flight. Not the average CAPACITY used. So a 15 minute flight would consume +/- 0.75 amp-hours from the batteries, or about 50 milliamp-hours per minute of flight. I will use up +/- 3,000 milliamp-hours of battery in an hour of flying. With two 4800 packs 9,600 milliamp-hours of total capacity on board I can get around 12 flights pushing the limits.