Please help with some calcs for the new build

[Gunter]

I am planning another build for me and my daughter to fly. The aim is to build it on a lightweight folding frame so that it's easy to transport and it will take a gopro camera...ultimately for FPV flying

Frame: Folding 500 size frame from Quadcopters, 4 motors, 280 grams
Motors: I already have some 880kv motors that are used for the Arducopter. Max. thrust 1380g at 20A, 210W
Esc's: 30A Arducopter
FC: Copter Control
Extra weight: Gopro HD with lightweight mount


What I need to know is:

1. What battery will give best flight times
2. What props are best suited (I would prefer a smoother flight opposed to max. speed and acceleration)
3. What flight times I can expect.

Thanks!

Gunter.

 

[DennyR]

OK you can use this formula to get an accurate estimation. 54 X bat. Cap. / total amps draw.
example:-
lets say each motor needs to lift 500 grams, so you have an AUW of 2000grams. On the MK site you can see some lift curves for a few of their motors. Lets assume your motor will draw 4.5 amps.at 500 grams of lift, therefore your total amps will be 18 if you have 4 motors. If your battery was 2.1 mAh then 54X2.1 / 18. Then you could fly for 6.3 mins.
These values are off the top of my head so they are not what you will get. But you can play around with battery sizes and weights to see the effect. As weight increases you will see a dramatic fall in duration and increase in current draw. Keep it light! If your duration starts to get below five mins. you are probably running close to the max discharge rate of the battery. If you add another battery then you need to look at the max. rating of the motors and the ESC in order to carry the additional weight.
Prop. efficiency increases with dia. and low pitch angles but that is also a function of KV value and speed that you want to fly at.

 

[Gunter]

OK you can use this formula to get an accurate estimation. 54 X bat. Cap. / total amps draw.
example:-
lets say each motor needs to lift 500 grams, so you have an AUW of 2000grams. On the MK site you can see some lift curves for a few of their motors. Lets assume your motor will draw 4.5 amps.at 500 grams of lift, therefore your total amps will be 18 if you have 4 motors. If your battery was 2.1 mAh then 54X2.1 / 18. Then you could fly for 6.3 mins.
These values are off the top of my head so they are not what you will get. But you can play around with battery sizes and weights to see the effect. As weight increases you will see a dramatic fall in duration and increase in current draw. Keep it light! If your duration starts to get below five mins. you are probably running close to the max discharge rate of the battery. If you add another battery then you need to look at the max. rating of the motors and the ESC in order to carry the additional weight.
Prop. efficiency increases with dia. and low pitch angles but that is also a function of KV value and speed that you want to fly at.

Thanks Denny, I shal sharpen my pencil and see what I come up with!

Gunter.