Dolphin effect after high speed looping

[jbod]

Hi,

I am very happy with the spirit on my 3 helis, except in one situation, interestingly on all 3 of them:

After doing a high speed looping with lots of pitch, I end up with a huge dolphin effect right after passing the "6 o'clock" (finished the circle).
This happens to my Diabolo 800, Goblin 770, Diabolo 550. It obviously cause a lot of noise and the heli 2-3 times does elevator up and down movement.

Setup is pretty much basic. What parameters should I look for? Before I used the Spirit I had BD3SX where this behaviour did not exist at all.
Cycle ring should be max. I can double check of course, but on all 3 helis it sounds like I missed something else.

Many thanks appreciate your support,
Andreas

[ZeXx86]

Hi,

you are right, first from all you should check, whether your Cyclic Ring is really at max. possible value.
If you configure too high collective pitch, then you can't set enough aileron/elevator range which may be needed.

The higher collective pitch is, higher cyclic range should be configured to operate properly, else your mechanics will be unable to compensate it.

Cyclic Ring allows that servos will not bind anywhere, but some flybarless units have not such feature so it can bind, but at the same time it can reach higher cyclic range (and possible damage something) - this could be the reason why it was possible to compensate it previously.

[Coco66]

Tomáš, when you talk about max possible value of Cyclin Ring, you mean even higher than the value of Pitch Range? I never understood if it's good to go higher.

[ZeXx86]

Yes, as high as mechanically possible without binding.

It is good to compensate any possible deviation even in fast forward flight - here it is very needed else the helicopter can pitchup very suddenly or even your rotation rates can't be so fast, etc.

[jbod]

Thanks for your fast reply.

I will carefully check the setting on my helicopters. So sounds like my collective pitch is to high compared to the cyclic ring limitation.
Is there a ratio I should keep in mind or just starting with 10degree pitch and decrease as long as I don't face the effect?

Andreas

[ZeXx86]

If you will be able to set same angles for collective pitch and aileron/elevator, then it should work fine probably in all cases.

[buell47]

If you will be able to set same angles for collective pitch and c, then it should work fine probably in all cases.

Hi Tomas,

nice to read this answer. Until now I had limited cyclic ring to max 10° for aileron/elevator (max. Pitch is 12.5)
Now I changed to 12,5° for cyclic ring. Mechanical binding is far away (even in -12,5° and +12,5° Pitch)

I had limited this, because of general setup suggestion of around 8° for cyclic Pitch.
Is this wrong? It´s not a higher risk of a boom strike? ( Goblin 700C and 550L Dominator)



Regards Frank

[ZeXx86]

You are right, that boom strike possibility is higher.
With bigger helicopter size chance is increased a lot, so you have to consider your helicopter model and its possibilities.

[buell47]

Hi Tomas,

okay...what is your cyclic pitch suggestion for a Goblin 700C?
The Manual has no values for cyclic pitch

Maybe better I go back to 10°?

[jbod]

I think key is to restrict pitch curve via pitch curve in the remote control and *not* via cyclic ring.

I checked the settings on my Diabolo 550 today and this definitely might have restricted the way the spirit can act. I used the first time soko heli tools and in the same time switched to the spirit. As you tell the sht (iPhone app) how much pitch you want this caused my miss-thinking.

But time will tell, hope to get out soon (rain).

Thanks again!
Andreas