eCalc - e Motoren Calculator

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xcopterCalc Tutorial:  How to build your next multirotor


eCalc is based on common physics and a mathematical model that is able to simulate the resulting flight characteristics of a multicopter by simply choosing your setup among the comprehensive database.

First you have to answer yourself a couple of questions:

  • What is my overall goal? (racing, FPV, filming,....
  • What....


After years of experience to simulate electric drives, we came across with this tutorial to help user to get accurate calculations in a systematic way.

The design process is iterative

1. Enviroment

Where you fly most?
The elevation of your field dios directly influences the air density and the performance of your drive.
Enter the typical enviromental data of your flight club first.



Entiremental Data

2. Multirotor Frame

What frame are you going to use?
The frame does define the possible rotor configuration, frame size and weight.
Enter the frame weight (with option "without Drive") and the frame size.



Frame Data

3. Rotor Configuration

What configuration you want to use?
In terms of a given frame size a coaxial configuration is always more efficient and resistant against rotor failure. In contrary a flat configuration is less expensive and less complex for the pilot.
Choose the total number of rotors and their arrangement (flat or coax).

Read more regarding Rotor Configuration...




4. Battery

What battery type you intend to use?
Most probably you are going to use battery packs you have already.
Define a adequate battery and there configuration.

The charge state (full, normal, low) is only used to evaluate self-measured peak values with fully charged batteries. For mean values use "normal".

When using customized batteries be reminded the data have to be entered per cell (not per pack!).




5. Controller / ESC

Which Electronic Speed Controller are you going to use?
Choose your controller brand or use a generic ESC (like max. 20A in the example)



Controller / ESC

6. Propeller

What is the largest prop that fits your frame?
Select the largest propeller in diameter that ensures the prop tip clearance against the other prop and the center hub. Remember the bigger the prop the more efficient your multicopter.





7. Motor

What motor shall I use?
That is the most critical part and needs some experience.

But don't worry, use eCalcs Prop-KV-Wizard:
With the above selection the Prop-KV-Wizard opens. Now, you have to estimate your all-up-weight (e.g. 1300g). enter your estimate and get KV range.

That gives you a clue for what motor you have to look for bei either use the search or the drop down boxes.





8. Calculation

If all selection is done hit the calculate button...

(This is the factory setup of a DJI Phantom 2 Vision)




8. Check results and refine

Does the results fits your goal?
Go back and forth, try other setups to refine your design.

How to interpret the results see the help section...