RC India

RC Equipments => Electric Power => Topic started by: krishnateja on April 27, 2013, 10:21:20 PM



Title: FLIGHT TIME
Post by: krishnateja on April 27, 2013, 10:21:20 PM
Hi guys ,

I am in need of a flight flying time calculator .my battery is 11.1v 2300 mah lipo ,motor EMAX CF2812 ,
20 amp EMAX ESC. Can anyone help me to calculate flight time of my airplane.And tell me how you calculated it.

THANK YOU.


Title: Re: FLIGHT TIME
Post by: paladugu_sujith on April 28, 2013, 10:55:01 AM
flight time is never constant.. it depends on carious factors like  type of aircraft , Throtle range used , type of flight( normal of sport or 3d) , environmental factors like wind ,etc.. but looking at ur setup.. you should get about 10-15 minuts of flight if used on a trainer or 15-20 minuts if on a glider with proper throttle usage.


Title: Re: FLIGHT TIME
Post by: Salam on April 28, 2013, 05:31:28 PM
This is how I will do my calculation. You will need to use a wattmeter to get your amp draw.
 
For instance a 2300 mAh pack has 2300 MilliampHours = 2.3 AmpHours. This means if your setup is drawing 2.3 Amps it will last for one hour. If your amps draw is double (4.6A) you can fly for half the time (30 minutes).
 
The calculation goes like; battery AmpHours divided by your motor current in Amps (at full throttle) and then multiply by 60 (minutes) to get minutes of flight on a fully (freshly) charged pack.
 
So if your motor draw is 20 Amps:
 (2.3/20) * 60 = 6.9 minutes of flight at full throttle.
 
With a 4000mAh pack it will be something like this:
 (4/20) * 60 = 12 minutes of flight at full throttle
 
Another way of calculating your flight time is simply by flying your model the way you usually fly it... lets say fly it for 6 safe minutes on a freshly charged 2300 pack, land and let the pack cool down so the resting voltage goes up as high as it can. Recharge your pack with a computerised charger and see how many mAh went into your pack. From there, you can get a good idea of how much flight time you can get out of that particular pack. Keep in mind the 80% battery useage formula. So if you have a 2200 mAh pack, and after 4 minutes of flight you put back 1200 mAh, that means you consumed 300mAh a minute. If you want to drain a 2200 pack to 80%, your usable mAh is 1760 which means you can fly for just a little less than 6 minutes if you consume 300 mAh/minute.

Note: Delivering all the available/usable capacity/energy of a pack depends on quite many things and conditions, i.e, ambient temperature, motor+ESC+wiring losses & inefficiency , amp draw, internal resistance, number of cycles on a particular pack, cells quality, chemistry of packs and brand does matter. I have noticed a few times that on a 2200 pack I was able to put back 2300mAh while the pack was used in a plane which landed safely without hitting LVC which means we do not know how do they rate the capacity of their packs so the mAh ratings are not true for some packs.

Also a wattmeter test to check your Amp draw on the ground (static) will pull slightly more amps than the plane actually flying in the air but this gives you a fair amount of idea about your Amp draw to calculate your flight time.

I hope this helps.


Title: Re: FLIGHT TIME
Post by: rcpilotacro on April 28, 2013, 06:21:33 PM
Very Nicely Put Salam ! cant be more clear than that, as crystal


Title: Re: Re: FLIGHT TIME
Post by: arun.sreelakam on April 29, 2013, 07:58:41 AM
Salam bro perfect lecture...  Thanks for the explanation...

Sent from my Canvas using tapatalk 2


Title: Re: FLIGHT TIME
Post by: Salam on April 29, 2013, 08:12:08 AM
You're welcome Bro! I am glad I could help.