Hi guys,

I would like to know the maximum load capacity of HJ450 frame. Also, do you know how the frame size is related to load capacity of quadcopter? I guess the power of motors also increase / decrease the load capacity.

some insights would be helpful.

Whats the load that you wanna carry? Loading capacity of frame would entirely depend on the material used for frame.

Load carrying capacity of the quad would primarily depend on the motor/prop combination and All Up Weight(AUW).

For eg, if you want to lift AUW 2kg including the copter and payload you would have to use motor/prop combination which generates more than 4kg thrust...i.e thrust should be atleast double the payload which will achieve lift.

Now if you reduce the weight to 1.5kg with the same setup, then your motors will generate the same thrust but will have more power at hand for attitude stabilization and flying in general because of reduced weight. Also longer flight times.
If you increase AUW to say 2.5kg with the same setup, then your flight time will decrease and so will maneuverability. Most probably it wont take off at all!

Similarly the maximum prop size thats suitable for the 450 should be 10". So you would have to find a motor which generates maximum thrust with 10" prop efficiently. And IMO you wont find motors which would be able to generate more than 1.2kg thrust with 10" prop. So you would need a larger frame to mount bigger prop/motors/battery to carry the load.

You can read more @ http://www.rcindia.org/multirotors/tutorial-how-to-build-multirotor-from-scratch/

the frame is made of glass fiber ( Q450 quadcopter frame )

I plan to buy an ARF quadcopter kit with that frame and try to replace the flight controller with a custom programmed on arduino 2560 and include additional electronics like gps, ultrasonic, camera and humdity/pressure sensors.

what do you think about this?

Bad idea! The frame would be able to carry the load but you wont have enough room on 450 without modifications. And it would be too cubersome to mount all this stuff. You should make a frame by yourself which would be easier or go for a bigger/lighter frame. You can do so with locally available material. A quick google search should provide you ample results on how to scratch build a frame.

And depending on the motor/prop/battery combination, an AUW of more than 1.4/1.5 kg on that frame would be max even if you use a 4s lipo with 9" props. Or you will have to find a motor which would generate 1.2kg+ thrust  with 10" prop at 3/4s lipo with decent flight time, which again I dont think is possible right now.

Sunnysky 2216 900kv on 4s with 10x4.7 prop produces 1.4kg thrust

Quote from: rcrcnitesh on December 27, 2014, 01:06:40 PM
Sunnysky 2216 900kv on 4s with 10x4.7 prop produces 1.4kg thrust

At what efficiency? And what about flight time?
Thats the maximum thrust. We cant fly a heavy copter at maximum thrust all the time.

It pulls some 15 to 17 amps.