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

Contact: Shrediquette @ g m x . d e --- All content published under CC Attribution-Noncommercial-Share Alike 3.0 Germany

More propeller tests

Recently, I discovered some small counter-rotating propellers that I didn't know before. I ordered some and did some tests. The red 4x4.5" props look really good, nice thin airfoils and a good precision. During the tests, they made the least amount of noise, and are currently my preferred ones. The performance of the 4x2.5" props is even better, but they have a pretty terrible sound and seem to be less balanced. Both propellers outperform the AirAce propellers, but this is not really a surprise because the AirAce have a smaller diameter and more blades. What is also interesting is the weight of the propellers. A propeller with a lower weight potentially has a lower moment of inertia which is beneficial for the control loops:
  • AirAce: 2.1 g
  • 4x2.5": 1.5 g
  • 4x4.5": 1.3 g
So this is an advantage for the 4x4.5" propellers, especially because the weight of this propeller is more concentrated to the center, which should further lower the momentof inertia.

The difference in endurance is quite dramatic, up to additional 2.5 minutes (+20 %) are possible when using the 4x2.5" instead of the AirAce.

Test setup

Left to right: 'AirAce', '4x4.5', '4x2.5'

Static thrust vs power input (@ 12 V)
Endurance vs take-off weight


  1. Kann man die 4x2.5 nicht gut ausbalancieren? Weil die Performance ist doch um einiges besser....

    1. Kann man bestimmt relativ einfach machen. Ich habe mich für die 4x4.5 entschieden, weil die deutlich leiser sind, ohne "Gefummel" auf die Motoren passen (und deutlich besser aussehen...)

    2. Danke. Ich möchte gerne mit den gleichen Motoren einen Quadcopter machen, auch mit CCD. Frame mit einem 3-D Drucker. Gleiche Prop für FPV-Fliegen.
      Wie hast Du en die 4.4x5 auf die Motoren fixiert? Klebstoff?. DU hast die Prop ja nur aufgesteckt, oder?

    3. Die Propeller sind auf 7mm aufgebohrt (Geht viel einfacher als bei "normalen" Propellern) und dann auf die Motorglocke gesteckt. Ein Tropfen Sekundenkleber sichert die Propeller.

  2. Super. Danke Dir für die Hilfe

  3. Great blog post and really helpful and your blog are very interesting.
    GATE 2018