Page 137 - Build Your Own Quadcopter_ Power Up Your Designs with the Parallax Elev-8

116 Bu il d Y o ur O w n Q u a d c o p t e r

perform before you select a motor and propeller combination. Choosing a video platform
would lead you to select a propeller with a high pitch and/or large diameter so that it could
turn at a lower r/min to produce enough lift for the camera, while minimizing vibrations.
You should look at smaller diameter propellers with medium pitch if you are looking for a
quadcopter that can perform aerobatics.

Comprehensive Quadcopter Analysis

I found an interesting website that will interactively create a set of performance characteristics
for your quadcopter based on information you provide: http://www.ecalc.ch/xcoptercalc
.htm?ecalc&lang=en. All you need to do is input these parameters:

• Overall quadcopter weight
• Battery type
• Select motor from a database list
• Select propeller from a database list

Then click on the Calculate button and you will see the results shown in Figures 5.27
and 5.28.
A wealth of information is in the calculation results, with much of it reflecting discussions
presented in this chapter. However, I suggest that you use the website data with caution, since
it has not been independently reviewed. However, it all appears to be reasonable and useful.
When reviewing the motor characteristics shown in Figure 5.28, I noticed that the motor
achieves about 80% efficiency when operating at 3 A or above. I also saw that the motor

Figure 5.27 Calculation results from the interactive xcopterCalc website.