My SK450 Deadcat with APM2.6 running 3.01 firmware is always pitching (flying forward) forward at neutral stick.
The Deadcat configuration is selected and pitch is setup correctly (so that when the stick is pulled back the PMW increases from around 1500 to 1850).
On the first flight I had to apply FULL back on the pitch stick to stop it from moving forward. After running AUTOTRIM and trying to use the SAVETRIM functions I was able to hover the machine at 50% back pressure on the pitch stick. I cannot get it better. All the other functions yaw and tilt was dialled in using the savertim and autotrim functions. I repeated the autotrim function more than once, no change.
I assume the autotrim and savetrim program function operate within preset limits, that is why it only trimmed the pitch out to a degree.
I am running Hyli 48-22 motors on 11x5.5 carbon props powered by a 4000maH 4S battery.
The machine is balanced at the intersection of the lines connecting the four motors.
Can anybody offer me a solution to get the deadcat trimmed? I cannot run the autotune function because it keeps flying away.
Thanks in advance
Replies
Same problem here,
Specs posted in the RC Groups section mentioned in this topic.
Same apm was used on a tricopter and a regular X quad (the original SK450 before DeadCat conversion) and are flying fine!
after every frame switch, I performed a full wipe, erase and calibrate.
- V frame selected has no influence on the forward drift (well drift, more like 20° pitch forward.)
- CG balanced to the picture posted with the red lines...
- Battery weight insufficient to pose real counterweight for a camera i'd like to install.
You also might want to check that your Transmitter stick positions are neutral calibrated. I had a similar problem and could not figure it out until I stumbled into the elevator expo set up and it showed my neutral was off by over 10%. I looked up the stick calibration procedure for my TX and poof problem solved.
Good question.
After reading over the RC Groups discussion, it seems successful flyers moved their battery further to the rear to move the CoG rearward.
It is worth a try. More than a few abandoned the airframe as unflyable.
I think it is just not very well documented.
-=Doug
When you state:
Do you mean like this the photo below?
Reading into that discussion reveals others have had similar issues.
-=Doug