Hey,

I just had my first few hovers on the T-Rex 450X I got from RC Expert a few weeks ago, after making a heavy-duty training-gear out of PVC pipes, long enough to make me feel comfortable. :-) Most of it was inside the ground-effect, but I got knee-high on some occasions. Inside the ground-effect, it would sometimes slide from side to side very fast and it was hard not to over-compensate. A bit higher up, it got a lot more stable. The space I had available wasn't very large (something in the order of 5x10 meters, I think), so I was still a bit careful. Tomorrow, I'm going to have a go in a sports-hall size (and height) empty floor at one of my employer's data-centers, which also helped a lot when I was learning to fly the Walkera #05-2. It's really a nice place to do some practise after work. You'd really have to try very hard to hit any obstacles, if you don't count crashing into the floor. :-)

Here are the adjustments I made to my RC Expert T-Rex 450X with Airtronics Sanwa RD8000 so far. I got the one with the carbon-parts.

- Pitch and throttle-curves it came with only went to 55% max power and pitch needed adjusting. Adjusted the 0-point for the pitch-servo and put in the recommended pitch and throttle-curves from http://www.trextuning.com Now it gets off the ground just above half throttle-stick (with the PVC training-gear on), with a decent head-speed.
- Gyro-sensitivity and tail-servo weren't adjusted properly. The way it was set up, the switch on the TX switched the sensitivity between 50% and 55%, which are both heading-hold mode. I set the non heading-hold mode to -50%. The length of the tail-servo rod seems to still need the adjustments described in the gyro's manual to have equal trim across both HH and non-HH modes.
- Blade-tracking was slightly off (about 0.5 - 1 CM). This was easily adjusted.
- Some minor adjustments to some of the linkage-rods, to make the angle of the round holes align with the balls on both sides.
- I set the dual-rate for the collective-servo's to 40% and added 35% exponential. This seems to help in "taming the beast". I didn't even have to move the servo-rods to the inner holes (they're all still in the outer holes) or add flybar-weights.
- ESC (Align 25A with governor-mode) came with quite agressive low voltage-cutoff at 2.52V per cell under load (which, after reading up on it, seems to be the default Align ships it with). I adjusted it to 2.73V per cell.
- The ("RC Expert"-branded, carbon-coated) 3200KV brushless motor that came with this set tends to run quite hot after just a few minutes at hover-speeds. RC Expert shipped me a free cooling-element for this motor, but I haven't received it yet, so I cannot yet comment on how much it will help. I programmed the PWM-frequency of the ESC from the 16KHz it came with to 8KHz, as I read somewhere that this makes it a bit more efficient (at a slight performance-cost), and that seems to have helped a little bit. FYI: My ESC-settings are currently: 1-1-2-2.

Except for the motor heating-problem, which RC Expert is very helpful in trying to solve, it's mostly pretty standard stuff you have to check and setup with any new heli, even if it's "RTF". I'm still of the opinion that RC Expert is a really pleasant seller to deal with and they offered me very intresting deals, with good service, so far. I'm mostly dealing with a guy named "Benny" there. He's one of their sales-persons and has been of great help. I still haven't had any other technical problems I couldn't solve myself and needed their help on, because I tend to look up most of the info I need on the manufacturer's sites, Google or forums like these. That way, I'll learn a lot more about the subject too. :-)

If anyone bought a setup like mine from RC Expert and has a problem with it, I might be able to help. Learned a lot while tinkering with mine.


Grtz,

Traveller