Actually, unwittingly you've brought the thread full circle. What you are looking for is something more similar to what's in my original build, and probably not similar to Sleepy's. Since that's the track I started down, it's all I've been searching for and reading about for about 3 weeks. By interweb standards, that makes me somewhat of an expert, so give what I'm about to say the weight it's due. :livid:
For longer flight times, you are looking for a magical blend of:
Lower AUW (All Up Weight) + slow spinning efficient motors (low kv) + biga$$ props + high voltage (6S)
I urge you to search the googles for "RCgroups 129 min flight" and take a look at that thread. The dood is using 4S but he's got FOUR packs of 4S, not 1. He also has the most minimal frame you can put together. He also can I expect do little more than hover (as slow spinning motors with big props will not be all that agile in the air). Hence searching for the nice blend of that equation.
If you're carrying a camera, gimbal, FC+GPS, landing gear, FPV gear?, and a decent sized battery, you're easily in the 2kg+ range. And if you want to actually be able to have some mixed flying instead of just hovering on a quad, you're probably not looking for a rig with 17-18" props. If you look at my build in the first post, and use that as a guide, you might get near what you are looking for. But, as the advice I got will tell you and what got me to here, it will be more of a beast than you need for a GoPro. You might think about the
5010 motors that are either 530 or 620 as a base and see what you can build from there. There isn't a lot of selection for 6S stuff that was in my price range, so that may be a challenge for you.
OK, now back to the sound engineer thread I started... :highly_amused: