G/Day
          Can someone try and  tell me what I'm doing wrong in my setup as I'm chewing way to much power out of batteries please 
My first setup   Cobra 2826/10
                      APC 12/6 prop
                      3300 4s battery
                     Igor,s. Setup 
 After Only a 5/45min flight it  had 20% left  then I tried a 5s 2700 only got 4Min's before it started shutting down cook the battery  3% left
Then I changed motor to a Cobra 3520/12 5s 2700 cooked that battery after 3.5Min's before started shuting down 7% left
OK then I went to Axi 2826/13. 6s. 3000 6min flight had 21% left  but I tried Allen resinger 11/5.5 3/blade now that setup should of  done it easy and didn't 
Model weights 59oz with 6s  55.5 oz with 4s     650sq wing

So all ran on the same esc n timer  so do I have a wrong setting in the esc because I'm sure I shouldn't be using this much battery
cheers Steve
I hope I explain my trouble properly

HI Steve,

Standard, well tuned combo with active timer Axi2826/F2b (Kv=700), Spin 66, 11x5" 3 blade prop takes maximally 2000mAh from 6s2700 mAh battery during 5:15s flight. That prop gives little more power than 2 blade 12x6 APC. So if I recalculate those 2000mAh to 4 cell battery, it is 2000*6/4 = 3000mAh or less (because of lower power). So I would say you are in good numbers, even better than I would expect :- ))

However using more cells of the same capacity will give you longer flight, but you will fall to worse efficiency because of too high voltage for your motor, so it is not fully proportional. The secret is to match battery voltage, prop pitch and motor KV to minimize voltage headroom of battery voltage to necessary voltage to maintain wanted RPM. That head room is different (smaller) for constant RPM setup and different for active tomers. I guess your battery does not have enough voltage for safe power boost in verticals. Does it accelerates well? Do not you feel less power end of fligh when voltage drops? If yes you will need to change something, but I guess 5 cells will be already too much.

 Thanks motorman cheers

Thank you for your advice Igor n Russell. Ok I have the cobra setup right now so I thought I changed the setup to a axi2826/13 running on 6s to try  and using 1800 out of batteries for a 5.30 min flight so looks like I have it worked out now as well . Just coming on harder in outsides more then insides so a little shimming to do. Thank you again for the help and see you at the nats Russell in two weeks cheers gentleman