This project was started in , electronics and control loops. Because I always need a cool project to learn new things, it was clear that something that can fly had to be built.
The project started as a "tricopter-only" project, but as I wanted to build smaller vehicles with more payload capacity, I decided to make some quadrotor, hexacopter and Y6 hexacopter firmwares too. My main interest is to build very small MAVs that fly as good as larger ones (or even better) and that can be controlled by wireless video link. I also experimented with autonomous flight in GPS-denied areas (video), and with GPS assisted autonomous hover (video).
-- William

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12" multirotor propeller tests

Recently, I tested some 12" propellers as I want to make a 12" hexrotor (nothing special, existing 3rd party frame). There are some different opinions about these propellers, but I was missing a direct comparison. I tested 3S (12 Volts) and 4S (16 Volts) and measured the thrust and the current on a test stand, simulating hovering flight. I used a RCtimer HP2814(3536)-710KV motor and an AfroESC 20A slim speed controller.

Here are the props I tested:
The propellers under test: APC Multi Rotor 12x4.4" ; Xoar Electric precision 12x4" ; Maxxprod EPP 12x4.5" ; Aeronaut CAM Carbon light 12x5" ; Graupner E PROP 12x6"
The results clearly show that the popular Graupner E PROP isn't really the first choice for hovering. It requires about 13% more power than the Aeronaut prop for the same amount of thrust during hovering flight. I think the chord length is too small close to the tip (I know that high aspect ratio wings have less induced drag, but here, other effects seem to dominate). The Graupner propeller also makes much more noise than the Aeronaut prop - which is the most quiet prop and also my favourite propeller. Interestingly, it has the largest (mean) chord length and the largest blade area of all props I tested. The APC multirotor is very similar, but has a higher weight. The Maxxprod is not stiff enough for these motor speeds and really shouldn't be used for heavier multirotors. I included it just because I had one lying around. The Xoar wood propellers are really beautiful, very well manufactured and light, but they have a pretty thick airfoil.
Here are the measurements:
Thrust and power at 3S (12 Volts)

Thrust and power at 4S (16 Volts)
The weight of propellers is also pretty crucial, as lighter propellers enable faster prop accelerations and decelerations which is advantageous for the flight stability. Here are the weights:

Graupner E PROP 12x6"21 g
APC Multi Rotor 12x4.4"22 g
Aeronaut CAM Carbon light 12x5"17 g
Maxxprod EPP 12x4.5"9 g
Xoar Electric precision 12x4"16 g

So, my choice is the Aeronaut CAM carbon light propeller (they exist in quite a number of diameters).

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