Long-term Memory

Trex600 time flown: 0h02 (cumulative model timer: 2h21)

Another try with the Trex 600, another crash… and again related to the rudder. Right after takeoff, the tail was oscillating heavily (yaw-wise, ~7cm amplitude, ~3Hz). I recognized this to be a gyro-issue so I landed and reduced the gyro gain from 30% to 20% (Futaba-scale). This settings still had oscillations, but they were slower and wider. Further reducing the gain (I went down to 5%) further reduced the frequency (down to ~1Hz), but didn’t stop the oscillation. Also, it became quite unstable as well.

Cyclic was still too sensitive, but I wanted to fix the rudder first; which turned out to be a wrong decision. Next thing I tried was switching to non-heading-hold mode. As soon as I switched heading-hold off, the heli started a pirouette and ascended. I managed to get it back to the ground, but with the sensitive cyclic I got myself a ground induced unscheduled maintanance.

Continue reading ‘Flight log 2012-07-28’ »

The Align manual doesn’t contain a list of spare part numbers. Luckily, the community took care of that (local copy of v1.7)

My first spool-up went rather well. The wind pushed over the rotor quite a bit, but I read that until the 3GX is actually airborn, it can’t compensate for anything. So I gave the throttle stick a push and indeed, the wind was compensated away. The controls were very sensitive; too sensitive for my taste; so I landed and increased the expo on the swash to 30% (it was 15%). During the next spoolup, there was a sudden “tick”, accompanied by a kick of the tail. Right after liftoff, the heli was pirouetting like crazy. Luckily I only was ~20cm high, so just dropping the pitch to -2º was enough to get it back on the ground without any damage.

I double-checked the gyro direction, the control direction and the direction of rotation; all seem to be correct. Until I took a closer look at the tail rotor itself:

The tail rotor hub had moved 6mm from the end of the shaft, and the set screw was gone. Moving the hub back into position was hard, it was jammed fairly hard.

After the build comes the setup. This post is mostly documentation for my own use.

Continue reading ‘Align T-rex 600E Pro setup’ »

After comparing half a dozen heli’s, and changing my mind every other day, I finally bought a replacement for my Raptor .50. The verdict became the Align T-rex 600E Pro. Since I was planning to use a Castle Creations ESC anyway, I went with the Super Combo.

Continue reading ‘Align T-rex 600E Pro build’ »