Hi everyone ,i am new to this drones world , i just wanted to build a drone myself but i don’t know where to start.
i want to build the drone myself with separately parts and a 3D printed frame, but first i have to know the propeller dimension to build the frame for that i have to know the weigh of the frame to choose a good motor to can handle the all thrust that i need…
First i found that the MT2206 2200 KV brushless motor would thank my requirements.
so i started to calculate how i’ve seen on forums;
- at 11.1v it need 16.2Amps so the total drone will need 4x16.2 = 64.8 A + amps for other electronics about 65/66A (so we need 66 amps for the installation - current drawn) - let chose a battery: i found the VENOM 20C, 3S, 5000mAh LIPO would be a good choise
5000mAH-5Ah -> 20x5 = 100A; so about 25 Amps for each motor minus the amps required for other electronics
- chose an ESC (i dont understand) - so the motor require only 16.2A each, if i deliver about 25A it will take only how much it really needs to run so it won’t burn or something , i understood that the ESC current must be at leas with 20% more than the motor required current (16.2A x 1.2 = 19.44 A - 20AESC) but i also have seen that the ESC current must be higher than the battery current delivered (25A x 1.2 = 30A ESC) soo it won’t burn (the amperage of the esc refer that it can support only 30A so the battery couldn’t deliver more of that or it need 30A to run the motor so the battery need to have more curent than the ESC to handle the requirement ??)
- finally the i saw the recommended Propellers - 6045 - and i god a total of 1067 grams for the hole drone that means 2x1067 = 2134g / 4 = 533.5 grams of thrust on each motor , this motor can handle this…
- BUT THE PROBLEM HERE IS THAT I’VE GOT ONLY ABOUT 15-18 MINUTES OF FLYING , THAT IS TO LESS THAN I WANTED !
After that i found a package with 4 motor, 4 ESC and 4 propellers(
motor - T-Motor AIR 2213/920KV
ESC - T-Motor 20A
prop - T9545
This kit is able to handle a 1200 g - 1500 g drone weight with a maximum 1084 g of thrust per motor with 18 A max current drawn -> 18 x 4 = 72 A + amps for rest of the instalation = 72 + 3 = 75 A
They have a recommended or included ESC of 20 A (if i calculate with 20% more of the motor current -> 18 A max current drawn x 1.2 = 21.6 A ESC NEEDED, if i calculate with the amperage value from that picture - 14.3 A at 14.8 Volts -> 14.3 x 1.2 = 17.16 A ESC needed) but if i will put a battery with a bigger amperage delivered i will burn the 20A ESC so i need a battery with max amperage under 20A of the ESC but bigger than the minimum curent needed (75 A for installation /4 = 18.75) so about 77.5 A battery.
If this calculation isn’t right and i can exceed the current of the esc with the current of the battery then is fine…
The commanded prop is a T9545 propeller with a diameter of 9.5 inches = 24.13 centimeters that is a huge diameter , for that i will need a minimum drone diagonal of 24.13 x 2 = 48.26, + 3,4,5 cm = about 50 cm long , that seems to need a huge frame so i will exceed the thrust needed for this motor so i have to chose a bigger one. Because of that i was thinking to pun a smaller prop about 6 inches = 15.24 cm because i found that the flight time will increase if ;
- i use a lower Kv motor with a bigger propeller = this motor will easy handle the 6 inches prop
- i use a lower Kv motor with a bigger battery and enough C rating
What is the C rating ? if i multiply the C rating with the mAh of the battery i will get the max Amperage drawn from the battery, which one of these things need to be bigger to get a longer flight time , the c or the mAh because the Amperage id the same if i will increase one and decrease other?