Short Flight times Hot motors ESCs, But super stable

[tleibe]

 



Hi I';m flying six of these: NTM Prop Drive Series 35-30A 1400kv, on a hexa 40a ESC 4s 4400 lipo 10x 4.7 APC props. only getting 5 mins flight times and hot motors escs hovering at 40% throttle, super stable in all modes except auto (pulses when moving forward) apm 2.5 running v2.9.1 Any ideas to increase flight times ???? (and stop pulsing in auto? solid on loiter pos and alt hold)??? Cheers Tim

[Biffa]

I';m no expert, but running 10 inch props on 1400kv on 4';s may be a little much.

I would come down to 8 inch props, you will draw less amps and have cooler motors and most likely see an increase in flight time also.

[guest325]

You probably are pushing the motors a bit hard, that said you';re using one hell of a lot of Watts there, how big/heavy is your hex?
Your low flight times are down to the Wattage - I make it about 3000 in total at full throttle. For the motors and esc';s to get hot at 1/2 throttle something has to be wrong.

[fruitsalad]

you are frying your motors and your escs wont last long before they pop,way to much power for escs and motors,
try 7x4 -8x4 on 4cell,or drop to 3 cell lipo..
your setup is pulling over 70amps at full throttle,your motors are rated for 45amp max..

[tleibe]

Thanks guys seems like its a conclusive not enough power for prop size, is there a formula that you guy use to work the correct power to prop size ratios out?

Thanks again For all your help :))

[fruitsalad]

use drive calc,
imput your voltage,select motor,and your esc in drop down menus..
then run through the different prop sizes to see which suits you best..

http://www.drivecalc.de/

[ChrisH]

Try this:

http://www.ecalc.ch/xcoptercalc.htm?ecalc&lang=en

It can be a bit confusing but have a play. It certainly sounds like the props are too big for the Kv of the motors. High Kv smaller props.

[ChrisH]

Great minds....

[Gaza07]

+1 props are way to big for 14400kv motors as suggested try 8"   

[fruitsalad]

+1 props are way to big for 14400kv motors as suggested try 8"   

for that kv youd need some serious tiddly props 

[tleibe]

Thanks again guys will reduce props for now but after later may upgrade motors etc any recommendations on bang for buck motors up to he job need to lift 3kgs including frame ?

Thanks again Tim

[guest325]

Thanks again guys will reduce props for now but after later may upgrade motors etc any recommendations on bang for buck motors up to he job need to lift 3kgs including frame ?

Thanks again Tim

I would have thought something like this should be good:
http://www.hobbyking.com/hobbyking/store/__29414__Turnigy_Aerodrive_SK3_4240_620kv_Brushless_Outrunner_Motor_UK_Warehouse_.html
I';ve used the SK3 series motors in Planes and found them to be superb value for money and pretty reliable, they';re a nice well made motor (and are built by the same manufacturer in China that makes the Hacker motors).

[tleibe]

Thanks darrellw will check those out:)