# How do I work out the specifications of motors and propellers for a quadcopter?

What will be the specifications of motors and propellers that can approx produce a thrust of 100kg in a quadcopter?

We are planning to lift a total weight of 50 Kg along with the 20 Kg weight of the quadcopter itself. So at 50% throttle the total thrust produced by it should be 150 Kg with a per motor total thrust of 37.5 kg.

I have looked at this answer to How to calculate quadcopter lift capabilities? but don't understand how to use this information to work out the specifications of motor and propeller required for my application.

The answer given in previous question is limited for small quad & I require the specifications of BLDC motor such as Kv,torque,Imax,V,Power,etc and of Propeller suitable for such motor.

• Are you talking about maximum thrust of 100kg? Or lifting a mass of 100kg? For how long? If you provide more information about what your doing amd what you hope to accomplish we can help you better Jul 9, 2015 at 20:25
• I voted to close this question because there are already answers to this question on this network Jul 10, 2015 at 6:17
• I'd like a thrust of 50 kilos from one motor. I'll use the motor for this. Help me Aug 11, 2018 at 2:24
• I'd like to thrust 50 or 60kg from one pea. I would like to use 200 to 240 kilograms of throttle using 4 such motor. I'll use the motor for this. Please help me. Aug 11, 2018 at 2:52
• Welcome to Robotics Md mamun, however on Stack exchange answers need to answer the question. If you have a related question, it should be asked as a new question (ideally referencing this one). Note that we prefer practical, answerable questions based on actual problems that you face. Please take a look at How to Ask and tour for more information on how stack exchange works. For advice on how to write a good question, see the Robotics question checklist. Aug 12, 2018 at 9:10

• Normally the larger the load the lower the KVA (RPM per volt) of the motor required and the higher the voltage required, as lower KVA generally indicates more torque.

• The larger the load the larger the prop required, a larger prop will produce more thrust at low RPMs but will require more torque to turn, choosing the right combination is key.

• For large high performance motors, Tiger motor is my favorite (their are plenty of other venders but they are the one I am most familiar with)

• For best performance in this size range I would choose the U10 range

• For best controllability you want the quadrocopter to be able to hover at 50% or less of throttle, with your crafts total mass of 70kg and with a desired 4 motor configuration the motor thrust must be at least

• 70kg/4 = 17.5kg or 17400 grams at 50% throttle
• Scrolling down you can see there thrust table and notice the largest thrust at 50% is 3254 grams (U10PLUS KV80@56v with a 30x10.5 prop), or 18% of what you need, you will need to go back to the drawing board, as in order to lift your load you would need 6 motors

• Assuming your frame had to motos regularly spaced your frame would need to be 1.3m in diameter, at hover drawing 1.6kW and at peak over 10kW

This vehicle would be impracticable to build and fly, what are you hoping to do? 50kg is a tremendous amount of weight, can you tell us specifically what you're doing? we could then give better suggestions of how to accomplish it.

• Thank u sirs for such a detailed reply ,but have a look at this video .The guy is the winner of hk beerlift. What specifications has he practically used to make it possible for quadcopter to lift a payload of approx 58 kg??.which u say is practically impossible.I m an engineering student of final year working on that project to practically make it possible to lift a payload of around 50kg. youtube.com/watch?v=VpW_B9NHwaQ Jul 14, 2015 at 19:04
• That person is doing a deadlift using well over 90% of the trust capacity of the motor is not nearly capable of normal flying Jul 14, 2015 at 19:06
• So can a 80kv motor witharound 30*8 inch propeller generate a thrust of approx 20kg at 70% throttle Jul 14, 2015 at 19:08
• Sure but the problem is not whether it will break but how difficult will be to control and running the motor at such a high power will consume an enormous amount of battery power Jul 14, 2015 at 19:10
• Can it max work for around say 4-5 min ? So that we can actually present a demo of it to our guides. Jul 14, 2015 at 19:12

Not technically a quadcopter, but if you use 6 Turnigy RotoMax 100cc motors, 24 inch props and 150A ESCs you ought to be able to get something close the the specs you are looking at. I used eCalc to arrive at these numbers.

some assumptions I made in the calcs:

• your vehicle has 'excellent' motor cooling
• it uses a 10000mAh 65C/100C 14s LiPo battery
• it uses 24"x12" props with PConst=1.3 and TConst=1.0

Notice that this vehicle:

• has a drive (motors+ESCs+batteries) that weighs 18.85kg