Showing posts from March, 2013

Director's Cut: A nice place to fly - Hexacopter in Cameroon / Africa

One of my videos - the MM6 cameroon video - received more than 1000 likes on Vimeo, and about one million views in total (until march 2013). Thank you all very much!! Here I present the Director's cut, showing some additional scenes and longer sequences.

Watch the video here.

If you don't know the original video, I recommend to watch it first, and then decide if you would like to see the extended Director's cut:

GEMiNi in the TV

A pretty spontaneous interview for a report on the new i-phone app of the European Space Agency (ESA).
Radio Bremen TV asked me to do a quick FPV flight in their foyer:

Video: ARD Nachtmagazin

Wind tunnel test data

This morning, I did some wind tunnel tests with the GEMiNi chassis. The GEMiNi was designed for FPV air races at high flight velocities, therefore the aerodynamic properties are important (well, it was also designed to look good of course...). I measured the aerodynamic forces generated by the frame (excluding the influence of the propeller's downwash) at a flight velocity of 12 m/s (= 43 km/h, maybe half the top speed) in a wind tunnel using a 2-axes force balance.

Angles of attack between 0 (hovering flight) and 90 degrees (vertical climb) were tested. The angle of attack is defined as the angle between the oncoming flow and the propeller disk. Both the lift coefficient (perpendicular to the oncoming flow) and the drag coefficient (parallel to the oncoming flow) were determined for each angle of attack (n = 3). The coefficients are based on the planform area of the copter.

Four different setups were tested:
"canopy-tilt-" refers to the hexrotor without canopy and witho…

Done. Looking forward to first outdoor flights...

What I really dislike in small copters is that they have the same amount of cables as larger ones, but almost no space...
The very first flights were done yesterday night. I used the default parameters from the BOLT S|2, and it seems to fly very nicely. There is a bit too much power, I prefer when my copters hover at about 50% throttle (like the BOLTs). This one hovers at 33% throttle. However, the GEMïNï is built for speed, and too much power will certainly not harm. It will also be possible to carry the GoPro HD Hero I think. The GEMïNï looks amazing in hovering flight...: Due to the tilted rotors, the tail hangs a bit lower than the rest (see my 3D animation), which gives it a crazy look :-D .

Here are some images I shot this morning: