Synergy E5ss 716 blades Low Headspeed Elevator bounce

[gta18]

Just finished setting up my E5ss 716mm edge blades, I'm getting elevator bounce on quick inputs during hover. What parameter should I tune first?

[ZeXx86]

Elevator Filter, this is exactly the parameter which should be used for reducing the effect.

[gta18]

I actually have it maxed out to 3 already and still getting the bounce.

[ZeXx86]

Max. value is 4 here.
What is your Cyclic Feed Forward value?

[gta18]

Sorry, I got the bank 2 on 4 and bank 1 at 3 and bank 0 at 2 on the elev filter.

cyclic ff if I recall right is set pretty high:
b0 = 9
b1 = 10
b2 = 12

flight charac
b0 = 5
b1 = 6
b2 = 7

[ZeXx86]

If Cyclic Feed Forward is so high (no more than maybe 8), then servos are not able to handle such rapid changes. This is the reason why you observe elevator bounce even with high elevator filter value.

I recommend lower values there.

If you want faster cyclic reaction (in other way than CFF does), you may try to increase Geometry 6° value by 10-25 (even that then it will not correspond to 6° mechanically). Also decreasing Cyclic Gain can make the reactions faster.

So then your servos should handle it fine.

[gta18]

Thanks! I'll Try that tonight.

[gta18]

Tomas,

Here's my setup files.

I lowered the cff down to 3 and raised the elev filter 2,3,4 on 3 banks ( now the files attached have the elev filter down to 3 only but during flight I had it at 4 on bank2)

I now am getting aileron shakes after flying around on bank 2. I still am getting the elevator bounce on all 3 banks, but not as bad when I had the cff at 12.

I also have increased the cyc geometry by 15 counts from 6deg so its around 8deg now

on this setup I get tail bounce on right yaw stops.

By the way I'm running
7s 4100mah pulse 45c
yep 120hv on active freewheel
100% straight tcurv
-14/14 cyc and 12.5cyc
14t pinion
106mm tail with 54/12t


I know that with this battery I am tail heavy, can that be the cause of the elev bounce too?

Maybe put 12s or 2 6s in parallel to balance the heli?


P.s. the aileron shakes showed up on 7s, none on the 6s.


What gains should I change (higher or lower) when I change headspeed?

I am planning to run it on maybe 1600rpm and 1300 rpm.

I've read that on other FBL's the D gain is supposed to get rid of this elev bounce, Which parameter would that be on the spirit?
Thanks
Arnold

[gta18]

Tomas,

Any updates?

[ZeXx86]

If there is wrong CG, then it can create such problems, especially with elevator.
So correcting this should solve your problem and maybe it can work with previous settings and any other tuning.

Parameter D you have mentioned is elevator filter. But if there is something really wrong, than it can't be fixed by this parameter.

You should have always good CG else you will need ultra fast and strong servos to make corrections fast enough.