Dfj f550 hexacopter help, motor selection???

[helloman1976]

Hey everyone, I've had about 14 FPV flights under my belt so far and I'm getting better at flying but the flight characteristics part I'm still learning and trying to understand; I come from airplanes and helis. My DJI hexacopter is a hobbyking knock off version by the way if that matters. Right now I'd estimate it weights around 3-4lbs maybe with all the FPV gear and everything. I currently have the Turnigy NTM 750Kv 265W motors on there and they have quite a bit of punch out power but seem to lag on maneuvering, or at least it feels like it should be snappier. I have the same motor but in a 1350Kv, Turnigy NTM 1350Kv 310W, so my question is would my hexa perform better with the faster 1350Kv motors or should I keep my 750Kv motors on there? The 1350Kv are so much lighter than the 750Kv I'm worried they won't perform as well. I did note that the 1350Kv's are rated at 310W versus the 750Kv's at 265W so I'm assuming that means they are stronger? I think the 750's are rated at 18A and the 1350's are rated for 30A, seems like a major jump to me? This is the part I'm really confused on if you can't tell lol...

So here are my questions based on the above.
1) Should I switch my motors out? Why?
2) Will the faster motor perform better? Why?
3) Will I use more power with the 1350's or save power because they are lighter etc?
4) Will I gain performance with the 1350's or is my issue more tuning you think?

Thanks!!!

 

[PeterLester]

There is interaction between dozens of factors, i.e., multirotor weight, battery volts, amps capacity, esc amp rating, motor rpm, wattage, prop pitch and diameters.
A 1350Kv motor is designed to operate over a very wide speed/rpm range relative to a 750 Kv motor which has fewer poles.
eCalc for multirotors can provide some insights as will the motor speed/torque curves.
Designing your own system requires both electrical and mechanical engineering skills/insights.
Or make modifications slowly and gradually asking the forums just one or two questions at a time.
Asking too many questions all at once makes it very difficult to get a knowledgeable response.
Hint: Design to achieve the optimum motor/prop combination so as to achieve a 30% thrust efficiency.