Also, I am thinking of getting this propeller:
(It's a 9*5 prop).
I am running hitec 81 servos, eflite park 480 motor, apc 9x7.5e prop, castle thunderbird 54 esc, turnigy 2200 battery, arora 9 radio. needed to put battery in very front with a 1300 lipo for cg but this is without fpv gear. plenty of cooling for electronis never got warm
over all i like wish it slowed down a little better and had a better glide, needs a bit more wing. flew well in a good breez. added a tail skid to protect elevator linkage.
I can't see how he could have gotten 15min, let alone even more than that. Based on my calculations, having the throttle at half speed would give a maximum 12 minutes - multiply that by .80 (because the efficiency of the motor is about 80%) and you have around 10 minutes. Additionally, he seems to be flying the plane fast so I'm guessing the throttle is set at more than 50% most of the time.
Also, if I may ask, why are you using a 4S battery pack? Doesn't the 480 motor require a 3S?
I am currently building one of these, and I have decided to use Tacon Big Foot 10 1100kv motor with a 3200mAh 4S 30C battery. Still waiting for the parts to come in, but I guess we'll see how my battery life is. I am documenting the entire build on my blog at www.johncm.com. Check it out!
So this seems a bit weird to me. Isn't there any battery that could provide the ideal, say, 30A of current instead of the high currents above (90A, 80A, 150A) and last for more than the flight times I've calculated above?
Additionally, if I only need 30A at max, would the battery then take the "left over" current and somehow provide a longer flight time? In other words, if I fly slow and only use up 15A on a continuous basis would I get a longer flight time than if I fly using 20A+?
The battery will last as long as the mah capacity relative to amps drawn. A 3000 mah or 3 amp hour battery with a motor drawing 3A would last 1 hour, 6a would be 30 minutes, 12a would be 15 minutes. How many amps you use depends on the plane, throttle management, and prop size. You really do not need a 30c or even 20c battery if you are going to use the large capacity battery that you stated, but because they are cheaper I would go with the 20c.
Also, having a battery that will deliver 80a and a motor that only needs at the most 30a really does not effect flight time. It just means you could power a motor rated at 80a max.
You should also be thinking about what prop to use as this is just as important as the battery. More efficient prop = longer flight times.
The 480 setup will be nice for this plane. A turnigy 35-36 1100kv would be even nicer.