Motor and prop size for 800mm hexacopter

[David ayre]

Hi I am building my second drone, an 800mm hexacopter. I am told that it could lift up to 9kg. Taking this into account I am looking for advice on motor and prop size to get the most efficient lift for longest battery life. It will be flown as a stable video platform. Any advice or guidance would be much appreciated

 

[Av8Chuck]

I wouldn't start by choosing the frame size.

Have you used eCalc? Not always that accurate but it's a good place to start getting an idea on the size of props, motors and power system you'll need to lift a given payload.

You need to determine the right motor and prop combination that can lift your target weight at 40-50% throttle. Too much less the the drone can become unstable and too much more is inefficient.

For an AUW of about 9Kg I'd start looking at 6S, 435KV motors, and 15" props. Lower 38oKv motors with 18" props would provide more lift and be more efficient but it depends on how heavy your frame and payload is.

Of coarse it's not only about the AUW. The mount of efficiency and weight you can lift is directly proportional to the size of your wallet...

 

[David ayre]

Ok I can look at 6s..... Still new to this is there a ubec /bec that will reduce that to the 12volts my on board video transmitter requires. Do I consider that half throttle is half battery voltage. Really thanks for replying it's very hard to find decent instructions and guidance.

 

[David ayre]

Of course within reason I am not concerned with the expense as long as the flight time is as long as it can be. As one of the planned places I plan to fly it us over water at scapa flow getting surface pictures after diving on the scuttled ships up there... The time is as a redundancy if the wind gets up on the return journey.