Not flipping straight

[craigjell]

I've recently purchased two Spartan VX1e units (latest firmware) and replaced the KBars that were on my Gaui X3 and Logo 600. Both machines are now flying 'sorta' okay but will need a lot of tuning.


Concentrating on my Gaui X3 1st, the main problem is that when I begin to do a flip it will roll just a few degrees - as if I'm putting in a touch of aileron input. So when doing flips or especially elevator tick-tocks, I have to constantly compensate.


I initially thought that maybe the unit wasn't completely parallel to the head/ boom but, its perfectly straight. Also, the pitch response is FAR too aggressive although the roll rates are great in 3D and BK modes.


I've gone through the heli setup wizard and selected 450 type heli and am using flight modes (sport, 3D and BK).


Has anybody else had these problems? Could it be phasing, mounting or something else.

[gazmk2]

Is the led a solid blue after its initialised? Also as I found out the vortex is a lot more responsive than a Kbar/beastx/gt5.1/3gx so if you inadvertently phase another control in the vortex will respond to this.

I used to be able to tic-toc half decently with a beastx, then after switching to vortex the heli kept pointing it's nose down. This turned out to be me phasing in forward cyclic with the aileron that the beastx didn't respond to but the vortex did.

[craigjell]

Actually I think the LED may have been solid red but I can check that in a couple of hours.... I'm 90% sure I'm not putting any other control in but I only have my experiences using other controllers and the sim to go off. I'll try a bit more aileron expo/ deadband and see if that helps.

cheers

[gazmk2]

A solid red led means it didn't get a perfect initialisation, usually it picked up a bit of movement while it was initialising.

[craigjell]

ahh - okay. I do usually leave it on the ground to initialise and thought the swash bump meant all was well. I'll make sure its a solid blue later before I fly.

[GravityKills]

Hi,

I don't know the Spartan unit. That said, the problem you describe could be phase error of the heli (not rotation of the sensor). Many helis need 10..15 degrees of correction.
My method to optimize this is first set up the tail very carefully. Then turn off FBL stabilization and change swash rotation until it flips straight.
You'll also recognize it when you set very high FBL gain and give sharp input. Phase error causes a fast wobble in the rotor disc without any clearly distinguishable axis.
But, as said this is generic advice, not specifically for the Spartan controller.

[craigjell]

I see - my next thought after sensor rotation was a possible phasing issue. The method of correcting seems sound but also quite complicated for me - I'm no newb but rarely venture into the advanced setups of any controller.
I'm going to have a quick tweek first maybe dropping the cyclic and tail gains, ensure its fully initialized before lift off and take it from there. If its no better - I'll look into changing the phasing etc.

cheers Craig

[waveydavey]

Craig are you sure it's not you adding a little aileron or rudder and the dead area of the sticks are different to that of the BeastX. On the Vortex you can add to the deadband and rudder expo.

• Rudder Deadband - This adjustment creates a small range around the rudder stick neutral where the gyro is not affected by rudder stick movement. Some pilots prefer a moderate amount of deadband as this allows fast collective pitch changes without accidentally affecting the rudder. The default value is negligible and primarily acts as a filter for minute variations when re-centring the rudder stick.

• Cyclic Deadband - This adjustment creates a small range around the stick neutral where the helicopter is not affected by cyclic stick movement. The default value is negligible and primarily acts as a filter for minute variations when re-centring the cyclic stick.

• Rudder Exponential - Operates in a similar way as exponential on the radio and allows using a different value for each flight mode. Negative values make the control slower and more precise near the stick centre.

• Cyclic Exponential - Operates in a similar way as exponential on the radio and allows using a different value for each flight mode. Negative values make the control slower and more precise near the stick centre.

[KevDavies]

I increase my deadband to 10 on my vortex units as I keep putting in unwanted inputs. Seems to help me a bit. Also if your swash rotation arms are on a collar make sur they are exactly 90 degres to the the spindle or this will cause an out of phase moment. You can adjust the phasing in the vortex, but I prefer to get it right mechanically

[myxiplx]

When you say flip, can I just check that you mean a flip and not a roll? I ask because you can get interactions with either, but the root causes can be very different.

My X3 with a Vortex flips lovely, it's very dialed in without any phase tuning, so unless I'm missing something with the way I fly mine you really shouldn't need that.

Definitely check for a blue light before flying, if the Vortex sensors aren't initialised properly it can lead to some odd effects in the air. Generally they're fairly minor, but if you're unlucky they could potentially lead to a crash.

Also, are you running expo in the TX or in the vortex? The vortex expo is great for piro moves, but I think it makes it a lot harder to do a clean tic-tock or flip. These days I'm actually using a little expo on both the vortex and the radio, so where I had maybe 20% expo before, I'm now running 10% on the vortex and 10% on the radio.

When tuning the pitch response, you can either go through the swash setup and give it a degree or two less pitch to work with, or you can just adjust your pitch travel in your radio. I've used either approach to good effect with Spartan units.

[craigjell]

Okay, so I took on a lot of the advice (thanks guys) and made some adjustments - I upped the cyclic deadband to 10 and dropped the rotor gain to 30% (from 35%) and took .5 degrees off the pitch. After 3 packs its definitely a lot better! I've now increased the rudder deadband to 10 so that should sort the flips and tick tocks out.


There is now a dolphin effect in FFF which I guess is pitching up so, I've dropped the pitch up comp from 8% to 6%.
I'll fly another few packs tomorrow evening and see how she fares.


myxiplx - what do mind sharing your values for rotor agility, style, gain and pitch up comp as a base reference for an X3?

[myxiplx]

The dolphin effect in FFF can also be too high a main gain. From the Vortex software:

"Rotor Gain ‐ Controls the amount stabilisation that is applied to the main rotor. If youexperience main rotor oscillations on hard stop manoeuvres (for example at the end of
rainbows) or porpoising during fast forward flight reduce this value."

On my X3 I'm running 2800rpm, 85 agility, 70 style, 35 gain, and 30 pitch up comp. Not sure how well settings translate from one model to another, but those are working fairly well for me.

[craigjell]

Thanks for those settings myxiplx - My rotor gain seems still too high because of the porpoising and cyclic wobble when coming into a hover but is currently only 30%!

Also, I've never really understood what 'robotic' meant regarding style but on my last flight it was up to 70% and it appeared the heli was almost trying to right itself after a flip or worse, mid tick-tock! I'm not used to it so was causing my flips to over-rotate so have now dropped this to 60%.

I think it's time for me to read-up on ALL of the extra parameter descriptions (and buy a datapod)

thanks again

[myxiplx]

Before you go too far down the rabbit hole with the advanced settings, take some time with the main gain and get the basics dialed in. It should be possible to get it behaving pretty darn well with just simple settings.

And there's no one right value for gains, the value you need will depend on your servos, the servo horn lengths you are using, your blades, and your headspeed! Just tune it so your model flies as you want it :-D

[craigjell]

Yep - sounds like good advice. I've just watched one of BK's setup vids and he says he doesn't really bother with most of the advanced settings.
I know where abouts I want my cyclic/ rudder expo and deadbands and that 30% rotor gain is flyable but still a little too high (for my setup). I'll put the pitch up comp back where it was for now and work on the rotor gain until it stops porpoising. Then I'll look at dropping the style values to get a nice feel.

cheers