NEED HELP IN BATTERY SELECTION

[sai vikas]

hello,
I want to know whether I can use a 1000mah 11.1v 3s 25c lipo on my ft racer with a motor combination of ntm series 28-36 1400kv and 8*6 slow fly prop....I want to reduce the weight...And what would be the flight time??

 

[pgerts]

I think that a 1400 with an 8*6 will be a little to much.
If you go down to 8*4 then you will probably be fine with round 20 Amps (max) and the battery will be good.
Flight times from 5 minutes to 10 minutes depending on your flying style. You will cruise the plane on round 3-4 amps but on full power it will be 1/20 h = 3 minutes.

 

[sai vikas]

I think that a 1400 with an 8*6 will be a little to much.
If you go down to 8*4 then you will probably be fine with round 20 Amps (max) and the battery will be good.
Flight times from 5 minutes to 10 minutes depending on your flying style. You will cruise the plane on round 3-4 amps but on full power it will be 1/20 h = 3 minutes.

I want to know that how we can calculate the flight time with respect to the esc,motor and battery capacity...Is there any speccific formula that determines the number of amps that motor draws with differnt prop sizes?

 

[pgerts]

The drawn amps is more than anything else depending on your flying style.
Unless - you are flying pylon with 100% throttle at all time.

For my own flying i am calculating with 30-50% of maximum power in normal weather depending on plane.
I can calculate down to 15-20% on a motor glider.
I will need a lot more when the weather is bad - like this passed days with 10 m/s average winds - (36 kph, 22 mph).

The maximum power is best known from tests you can read for your motor and propeller on the net.

Example : 10 Amps and a battery of 1000 mAh will give in theory 1/10 hour = 6 minutes.
You will normally not go under 80 % giving you more like 4-5 minutes flight at full power and 2 to 3 times that on cruising.