Thursday, March 22, 2018
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How to check the motors’ thrust ?


When you are preparing to DIY a quadcopter and have chosen your motors, next you should check the motors’ thrust, so how to check the motors’ thrust? There is a data table for a  motor, now let me tell you how to check the motors’ thrust like this motor.


From this table we can get many useful information about our drone’s motor. We can see that this manufacturer has tested this motor with two different voltages (2S battery (approx 8V) and 3S battery(approx 12V) ), and a number of different propellers (called paddles in the above table  ). We are then given the amperage that the motor pulls, the thrust that it produces and the efficiency (thrust in grams/power in watts), as well as some other information. We can see from the table that with a 3S battery, these motors will produce enough thrust with 5×3, or 6×3 propellers which produce more than the required 300g each.Comparing the efficiency

So, the first port of call is arguably investigating the thrust produced by the motors. To further differentiate between motors, it is my belief that efficiency should next be considered. The efficiency is commonly expressed as the thrust divided by the power used in watts or g/W. The more efficient a motor is (or the bigger the g/W number is), the longer the copter will fly. A general rule of thumb would be anything over 7 for efficiency is good, and of course, the higher the value the better. Some of the larger motors (BE 81081.0k) have an efficiency (g/W) of over 18!

Once you have found several motors that produce the required level of thrust an easy way to choose the best one would be to get the most efficient one, but this will also usually end up being the most expensive one.


However, as mentioned previously in this article, this may not be your priority. You may want small, agile copter for acrobatic moves in the air, in which case you want high rpm, and the efficiency will necessarily take a hit which is usually the case for high KV motors. In our example we are choosing a motor for a mini quad, so the type of motor you would use for these copters is one like the MT2204, the table of which is shown above. This is why the efficiency of this motor is relatively poor.

Checking the motors thrust is one part of build a quadcopter, and you must know how to choose a right motors first, you can read “The guide to help you choose motors for your quadcopter and multirotorto teach you how to choose a right motors.

Related articles:

  1. How To Choose A Motor
  2. Motor Basic Knowledge Introduction  
  3. Tattu 2305 2450KV Brushless Quadcopter Motors
  4. The guide to choose motors for your quadcopter and multirotor