Brain - “floats a dolphin style”

[pheek]

Hello,
I’ve got a problem with setting of my Goblin 380. When going forward and using the collective up and down, the helicopter “floats a dolphin style”. The centre of gravity seems to be ok. I use Brain stabi. Can you give me any advice for what to change in the setting to stop this activity? Can anyone send me the Brain setting from their Goblin?Thanks a lot.

[mamartin]

Raise the cyclic gain in the basic setup menu under (tab 11).
This is also where you select which ever one of the default flying style presets that suits your style best to start with.
If you have bank switching setup you can mirror your setup in all 3 banks and leave the first bank at default, raise the second bank up 4 or 5 points and the 3rd bank up an additional 4 or 5 from there even and fly it again and try all 3 and see which is best. If it still does the dolphin style forward flight raise them all up more and repeat.
Till you get it flying more to your liking.

[HeliWobbles]

I dint know if the problem I have is the same but I get an elevator "bob" on the exit of fast big-air loops. The faster the speed, the more the bob. I am careful to not let the stick flick back to centre so its not the spring. I had the same issue when I had the unit on my 450x as I do on the Forza 450 now.

It's not a big problem but does give you a spooking when it make a little dive toward the ground when you are already low and at full-noise. To overcome it I have learned to slowly ease off the stick on the exit but I know it still isn't right; I have never had the same issue with other FBLs.

Any hints on what to look for in setting cyclic gain? What maneuvers would I expect to see it? Sport flier only here, so no tic-tocs and hurricanes etc.

Thanks.
Ted

[crashjack]

There is also a Tail Drag setting to counteract head-bob on pitch pumps during FFF. Worried about oscillations and vibrations with continuing to raise cyclic gain, I started adjusting the Tail Drag. My question is similar, how far do you go with increasing cyclic gain before you start adjusting Tail Drag.

[HighFreq]

Originally Posted by HeliWobbles

I dint know if the problem I have is the same but I get an elevator "bob" on the exit of fast big-air loops. The faster the speed, the more the bob. I am careful to not let the stick flick back to centre so its not the spring. I had the same issue when I had the unit on my 450x as I do on the Forza 450 now.

It's not a big problem but does give you a spooking when it make a little dive toward the ground when you are already low and at full-noise. To overcome it I have learned to slowly ease off the stick on the exit but I know it still isn't right; I have never had the same issue with other FBLs.

Any hints on what to look for in setting cyclic gain? What maneuvers would I expect to see it? Sport flier only here, so no tic-tocs and hurricanes etc.

Thanks.
Ted

To eliminate "elevator bob" go into advanced->setipX->cyclic and raise D gain for elevator at 5 points at the time until gone.

Corrado

[pheek]

Raising Cyclic Gain didn't help. I raised it from 31 to 45 and no result. What happens if I exaggerate this value? The Goblin 380 still "swims the dolphin".
When setting G380 I used the 450 size. I put expo elev and ailer to zero and Feed Forward Gain in Ailer and Elev to 20. This is the only difference compared to default setting.

[TR450ZS]

What length are your servo horns at? Perhaps try moving the ball in a little closer if your servo horns allow this, or try shorter horns

[pheek]

According to the SAB manual I should set 13-15 mm from the centre of the ball to the centre of the screw and I've got 14 mm. Do you think this could be the problem?

[HighFreq]

You can add some tail drag compensation, it is intended to solve the issue you have.


Corrado

[pheek]

I would like to ask - when the helicopter goes nose up after applying pitch up should I compensate it into plus or minus numbers?

[crashjack]

Originally Posted by pheek

I would like to ask - when the helicopter goes nose up after applying pitch up should I compensate it into plus or minus numbers?

Something I would like to know as well. I tested my head-bob in FFF today, and it looked worse. Now, I'm flying harder/faster than when I was originally testing. Also, motor was bogging in the earlier tests so that might have dampened the effect. I'm at +10 Tail Drag Compensation and not sure if I need to keep going higher, or go negative.

[mamartin]

Originally Posted by crashjack

Something I would like to know as well. I tested my head-bob in FFF today, and it looked worse. Now, I'm flying harder/faster than when I was originally testing. Also, motor was bogging in the earlier tests so that might have dampened the effect. I'm at +10 Tail Drag Compensation and not sure if I need to keep going higher, or go negative.

Try setting around -6 and see what it does there.
Most people found that -6 was the happy value

[crashjack]

Thanks! I'll try it.

[Syfon]

Hi,
@crashjack: how are your testings? I am looking forward to hear, as I am experiencing the same issue with my 450. I have increased cyclic gain up to 60 which is maximum, but without satisfying results.

[crashjack]

I haven't been able to fly since I changed the Tail Drag Compensation to the -6 setting. Weather permitting, I'll be flying this weekend and will post results.

[bladebuster.rc]

Originally Posted by pheek

Hello,

I’ve got a problem with setting of my Goblin 380. When going forward and using the collective up and down, the helicopter “floats a dolphin style”. The centre of gravity seems to be ok. I use Brain stabi. Can you give me any advice for what to change in the setting to stop this activity? Can anyone send me the Brain setting from their Goblin?Thanks a lot.

Generally i solve by decreasing elevator P gain in advanced menu.

[crashjack]

Tested Tail Drag Comp. at -6 and that's got my head bob in FFF fixed. I didn't dwell on testing it, but a couple of pitch pumps in FFF showed no significant head bob. I'll give a few more tests and might need to adjust another -1 or so, but there is a night and day difference with the new setting.