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Old 12-27-2020, 02:46 PM   #1 (permalink)
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Join Date: Dec 2020
Location: Alaska
Default Heli bobs up & down during forward flight

So, I have seen this issue raised on the blade 230s form and have experienced it on my blade 230s as well (of course a different flight controller). I could not tune out the tail wag with the AR636A on my blade 360cfx 3s. So, I installed the FC6250HX on the blade 360cfx 3s and wam bam no more tail wag! But unfortunately, it bobs up and down now during forward flight at speed. Low speed forward flight it is fine. Stability is off and have not set it up nor do I plan to same thing with SAFE. Mechanically it is solid pretty much anew bird. New main shaft, spindle, tail rotor shaft, blades, new HV servos, Spektrum smart esc. The filmware is up to date on both the flight controller and esc. And yes, I did recalibrate the flight controller.

In forward programing under the safe menu, I have lowered the stability gain and envelope down and I have no idea what attitude trim is but lowered that as well. I am shooting in the dark here with these adjustments seeing how there is no information out there on what does what in these sub-menus. Any help would be appreciated, I am looking forward to throwing this bird around!
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Old 12-30-2020, 10:15 AM   #2 (permalink)
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If you have stability turned off, the settings in the safe mode windows shouldn't change anything. I'm assuming you've already messed around with your cyclic PID's (Fwd Programming>Swashplate> Pitch and Roll)? What flight mode is this in (normal, stunt 1, stunt 2)?
Blade Fusion 270, Blade 360 cfx
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Old 12-30-2020, 12:10 PM   #3 (permalink)
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Make sure the model cg's on the main shaft before each flight, being nose or tail heavy can lead to porpoising in fff.

Worn dampeners or sloppy swash can lead to similar issues.

Try raising the P and I gains for both roll and pitch cyclic to 70.

Let me know if the issue has been reduced.

SAFE->Attitude Trim is used to trim the attitude in SAFE panic or stability modes. Defaults of roll = 450 (4.5 degrees) and pitch = 0 are correct for most clockwise rotating helis.

Horizon Hobby, LLC
My Projects: 150 S, 200 SRX, 200 S, 230 S v1/v2, 270 CFX, Fu270, Fu480: AR636/AR6335 Heli, FC6250HX, AR6250MHX

Last edited by brianbremer; 12-30-2020 at 11:31 PM..
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Old 12-31-2020, 07:08 PM   #4 (permalink)
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Join Date: Dec 2020
Location: Alaska

In all flight modes it bobs. The CG is good. I did slowly raise the P & I gains and ended up at 80. It did reduce the problem so the next thing I will do is replace the dampeners. I thought it might of been the wind, so I got the stock 360cfx 3s out and it ran true and straight at full pitch... So it was not a wind issue.
Guess I should disclose that the warmest I ran the heli is maybe 25 degrees F, but not colder than 15 F. So I guess the dampeners could be contracting along with who knows what else. And the next 4-6 weeks will be the coldest part of winter so I probably will not be flying much.
Thank you for the knowledge.
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