A power system’s key components: brushless outrunner motor, ESC and battery pack. When matched and running efficiently, they produce a lot of power.

For many, E-power is a sort of mystery, but we all know that it’s a clean, very quiet power source- attributes that appeal to many flying clubs whose members worry about losing their field because neighbors frown on their noise. How should you pick right power system for your park flyer? How can you tell whether you’ll be happy ...

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Updated: July 16, 2015 — 10:15 AM


  1. Thanks, nice post! But if you calculate the watts/oz. won’t you suppose that the plane need to fly at full power continiously to fly well??? (Srry for my bad English, it isn’t my native language.)

  2. If you cut off the battery plug be careful you don’t short out the battery when adding a new plug!

  3. Correctly sizing the prop for the plane and power system
    is just as important as everything else.

  4. What about static thrust? I find this a very useful parameter to know and gives you the information needed to optomize performace of the motor/prop/battery combination.

  5. A good article, John, but you erred when you said, “Multiply this rating by the pack’s capacity in mAh to determine how many amps can safely be pulled from the pack.” You should have said “amps” there, instead of “mAh”. Your examples use amps. Many who are new to e-flight are confused about amps versus milliamps, especially when trying to figure out how many amps to set on their chargers. Chargers are rated in amps, ESCs are rated in amps, and motors are rated in amps. Why are batteries still rated in milliamps?

    I’m glad that many battery vendors are doing the math for us and printing the continuous and burst/peak discharge ratings on the battery label, but that’s in small print below the big print that proclaims the battery’s capacity in mAh. It no longer makes sense to label the battery with mAh.

    Please use your influence in the industry to get the vendors to start labeling their LiPo batteries in amps. It’s time to make the change.

  6. Sorry for my tardiness in replaying guys, I was traveling, covering the XFC.

    I agree with you Eric Static thrust is a good parameter to know. Is there a way that you use to measure the static thrust? Or anyone else who has a suggestion, I would like to know how you are accomplishing that.

    That is a good point; although I believe my math is correct in the examples, having to convert mAh into Amps is a bit of a pain. But the simple way to remember is that a 1000 mAh=1 amp (hour). For Example an 800mAh pack with a 10C rating can provide only 8 amps continually (10 x 800 mAh = 8,000 mAh or 8 amps).
    I always like to think of it this way a 4500 mAh pack is a 4.5 amp pack.

    Unfortunately Joel, I think we will be dealing with mAh packs for some time to come. It has become the standard in the industry and most likely not to change anytime soon. But I do agree with you I like how they are now letting up know the amount of Amps you can pull out of the battery, so we don’t have to do the math. I hate math.

  7. Trust me Elmardus your second language is way better than I would be if I had a second language. I have enough trouble with just speaking English, and I mess that one up all the time.

    You are correct in assuming that, you would have to fly the plane at full power. Just a little history here on that chart, it came out some years ago when the batteries and motors were nowhere near as strong as they are today. So we did have to run everything at full power just to get it to fly.

    But I think you could multiply the watts in that chart by 125%, that way you would be flying at 75% full power and not be so hard on the power system with a little in reserve if needed.

    And John (another John, not me) is absolutely right, matching up the correct prop to the system makes all the difference in the world to the performance of the plane. But that can be a whole another article in itself.

  8. im trying to make a plane it come to around 320kg weight i want to make it travell ar 200 km/hour for 90 to 120 minutes hours its wing span would be around 3 to 3.2 foot what should be the power of the motor and is there any other factors that would have any effect on the plane

  9. Excellent article, it’s taken some of the mystery out of setting a plane’s electronics up but i’m still learning. Your explaining isn’t the trouble, it’s more like i’m a bit stupid ! I’ll get there in the end,,,,,I hope LOL.

  10. Can a receiver blow if you have a 3 cell battery 11volts and the receiver requires 6volts. And I made a scale f-15 jet and I want to know what motor to put on it (A EDF Motor or Just a nice performance motor 2200kv to 3000kv outrunner motor) and a 5 or 6ch transmitter or receiver. I want to know what’s the best combo of electronics to put on this jet.

  11. Good article – thank you

  12. Hi,,

    I have a Extreme Extra 300 E It weights in at 2KG made of wood I have bought :-
    ESC = 92amp(Max) 3s (Max) 13v (Max)
    Batt = 3s 11.1v 3200 A spec lipo 65c
    Motor = 550 3800KV Sensorless Brushless Motor 4 Pole
    Wood Prop = either 15×8 or 15×6
    HAVE I MADE ANY ERRORS ?????????????

  13. hallo …in youtube i saw that one plane used two 5.0 amp batteries in parallel = 10000mah/10 amp , idont know the C rating .. say it’s 20 amp battery so battery amp is 10*20=200 amp ..but they used 60 amp ESC … BUT as we know esc amp should be higher than battery and motor if its not, then it will get hot and as travelling 60 minutes it will caught fire .. so how it’s possible to use 200 amp battery eith 60 amp eac …please tell me. describe please …

    best regards

    1. The size of the ESC is based on the amount of current use by the motor, not the size of the battery. The size of the battery, is the amount of amps it has stored up inside its cells, not all of this will go to the system at one time. its like your car, you have a 16 gallon tank, but the engine does not suck up 16 gallons at one time, it take in a small amount so that eventually it uses up the entire tank.

  14. I have a 1943 Berkeley Custom Cavalier. It’s total weight without any power, radio, servo, prop, battery, ESC components
    Is about 12 pounds. I know little about electrics. I need assistance to equip the plane and start a period of taxiing and ground control practice. Am open for business. I invite comments.

  15. This article was extremely helpful, but your link to the “electrifly” website was unspecific. I was unable to find the “motor selection assistance” page or graph or program, what ever it was. But with the valuable info you gave in this article, I should be fine. Thank you.

  16. Great article and very helpful. However the section on motor selection was, IMO, a bit oversimplified. No mention was made of the Kv rating of the motor and this is extremely important. A plane designed for speed or EDF wants a higher Kv rated motor while a trainer, STOL or other performance requiring low-speed high and power will require the higher torque of a lower Kv rated motor. These factors must be taken into account before settling on a motor and then choosing a prop, ESC, etc. etc. Otherwise, good stuff here.

  17. I am making a bwb rc plane using foam, empty weight of aircraft is around 400g, to my estimation, batteries and servos will add up to make the total weight of around 2 kg. I wish to use 2 ducted fan to propel the plane, can you please guide me about the size of ducted fan required, the battery required, the speed controllers ?

  18. I still don’t know what battery to use for a 20 size motor

  19. Trying to match a 20 size combo motor to tha correct battery

  20. i have purchased a 1000kv brush less motor in specification write max(p)=190/3 and biggest thrust(g/s)=1200/4 sir i want to know what means of specification

  21. May peace and prosperity be with you!
    Hi, i am new to custom rc models. I build a F-16 weight (640g including battery) and its is hovering or stalling here is the video link,
    Plane material :5mm foam board,
    Size: (L*W) 1025mm (41in)* 787.5mm (31.5in)
    Motor: Racerstar BR2212 1400KV (40g),
    ESC: 30A,
    servos: 9g*3,
    Tx,Rx: FlySky fs-i6,
    Battery: 1800 Mah 11.1v, any suggestion to stop the stalling

    1. Looks like you need to find the center of gravity and balance your plane.

  22. I am using 2200kv brushless motor for rc plane …what ampere of ESC and how much MAH. Battry should i have to choose ?

    1. hi use a 40amp esc if using a 2cell 6×4 prop 3cell batt use 5×5 prop the size of mah is up to you and the size of plane ballance and what fits in duration of flight req etc

      1. sorry correction if using a 2 cell batt 7×4 prop not 6×4 as i previously stated Akash

  23. can i use 1500mAh 20C lipo for a2212/t13 battery with 10A?
    will it fry my motor ?
    u said dont use ESC with 3 times the ampere u need. so it i use 30A ESC will it affect my motor ?

  24. Correction:

    3 cell not 30c

  25. Hi !I am using a 2200pmah battery 10c ,motor of 1200 kv motor ,and an esc of 30amps.Does this combination work perfectly.The same combination has crashed for 2 times

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