Calculating Run Time
 

I am new to the electric side of the hobby but wanted a small fun electric to fly in limited area and make it quick outing unlike taking my glows out. So I got a Hanger 9 Mini Ultra Stick with the following power components. I am trying to figure out how much run time I can get out the bird before I lose it. Any help would be greatly appreciated.

E-Flite Park 400 Outrunner 920Kv

ElectriFly 1250 mAhr 11.1 V LiPo 3 Cell

E-Flite 20-Amp Brushless ESC (V2)

RE: Calculating Run Time
 

Waross: You have to know the amp drain on the battery. Here's a link to a flight time computer.
http://www.bphobbies.com/view.asp?id=A0320048&Nav=7
Bob

RE: Calculating Run Time
 

If you would like to calculate it yourself, the formula is:

http://www.astronomyboy.com/brushles...me_formula.gif

Current consumption and battery capacity must use the same units of current. It battery capacity is expressed in mAh, then current consumption must be expressed in mA.

Example:
battery capacity is 2000 mAh
power system draws 25A = 25,000mA

2000/25000 x 60 = 4.8 minutes

- Jeff

RE: Calculating Run Time
 

Here's yet another online calculator
http://www.missionwings.com/flighttime.asp

Keep in mind though that milliamp ratings listed on the packs themselves are theoretical maximums. I'd be more inclined to say actual flight time is probably 80% of what the calculator gives.

RE: Calculating Run Time
 

Yes, the calculators and formula provide rough estimates only. They don't account for efficiency, optimistically rated batteries, your LVC setting, etc.

- Jeff

RE: Calculating Run Time
 

So how do I figure out power drain of the motor...???

RE: Calculating Run Time
 

You don't figure it out. You measure it with a wattmeter. A wattmeter is an essential tool if you are serious about e-flight. Without a wattmeter, you are merely guessing about how your power system is performing.

That said, someone here may be familiar enough with your set-up to estimate the current consumption.

- Jeff