Some HK401b and SuperBrain issues (newbie!)...

OK, to set the stage, it's my first heli and my first RC model in ~20 years (never to late to get them toys you never got as a kid, right :-). (for those of you that want to skip right to the questions I put them in bold):

Anyway, I have a HK450 Pro belt and all the tools to properly build it and set it up correctly. Tx is a Spectrum DX6i, ESC is 40A SuperBrain (with USB-dongle for PC connection), external 4A switched BEC, HXT900 for cyclic and HK401b gyro (with the usual mods) + HK-922MG for tail.

Today I fianally was satisfied with the setup and took it down to the local field and spooled it up for the first time. I did not really know what to expect -how close to the simulator it would be.

Fist of all, it looks like I can't get the SuperBrain ESC to do soft starts. It just opens the flodgates, so to speak. Not a big problem since i have my heli setup with very small negative pitch range so I can spool it up using the pitch for now.

The second part that scared me was when I engage the throttle hold on my DX9i, and then flip it back the heli spools up to a low speed with the stick at 0. It turns out that throttle hold will put the throttle lower than 0 (even though my TH cure is programmed to be flat at 0). I ended up increasing the TH curve to about 10% and with the monitor function I checked that the throttle did not go lower than my "0" position in normal mode. Is this the way to do it or am I missing something? Do I need to calibrate the ESC differently?

OK with that done I decided to spool it up to mid stick (80% throttle and 0 deg. pitch) to tune my gyro settings. It was chasing like crazy. Even at 57% it chased, but at 56 it wasn't. This, I understand, is symptomatic to the new batch of 401b's (but I did not know about this difference until after this first flight...).

As it turned out I must have managed to setup the heli really well because it felt suprisingly smooth and no vibration or shaking to speak during spool up so I decided I'd give it some more thrust and off we went :-). Insanely nice feeling getting it of the ground for the first time and beeing able to hover it.

After a pack of hovering I decided to step it up a notch since everything felt smooth and stable enough to continue so I switched to a new pack, hovered for a minute or so and then transitioned to some "easy" pitch pumps and fast +-30 degree tail movements to check how the gyro held up and this is where I'm not really satisfied. It dosn't hold that well at all and it feels "saggy" (I can only compare to RealFlight 6 and the 450 models I have flown there). I think I need a more gain, but if I go up it will start wag, and since the gain must be set so insanely low (56-57%) a .5% step, which is the smallest I can do with my TX is actually a huge step up since I only have 6-7% of span before it goes chasing. I have a little play in the tail blade assembly but I'd say it's pretty little. Also i noticed it was taildrifting a bit, which was kind of annoying as it got worse over time.

So, should I ditch the 401b and get say a GA-250 instead? Should I change to another gyro?

I obviously got the new revision of the HK401b and it just seems so
much more sensitive/nervous than the old one. I've tested all ball positions and several different tail servos with no luck. With the ball in the closest position I still can't go above 56%.

I just can't get my 401b to perform even half decent so I'll just switch to another model since so many report issues with the new revision. To bad I did not read about the sensitivity issues before I ordered the 401.

This time around I ordered a Turnigy Mini MEMS and I also added a HK GA250 to the cart to use as backup.

Edited by krineH - 04/Jan/2012 at 2:25am