How to adjust tracking?

[heli227]

I can see the pitch tracking is off by about 3mm. How to adjust it?

[MariaFan]

An easy way to set your blades to 50% (zero pitch) is to set a pitch curve to be 0 - 50 - 50 - 50 - 100%.
This way, you are basically only going to have 0, 50 and 100 pitch.
When you are at 50, turn the main shaft until the blades are straight left and right.
Then, keeping the rotor head in place, move the blades forwards (or backwards).
At 50%, they should be the same height.
If not, adjust the servo links until they are.

Also, the difference in height should be the same at 0% and 100%, except in opposite directions.

Your swash plate should be level when you are done.

[heli227]

Originally Posted by MariaFan

An easy way to set your blades to 50% (zero pitch) is to set a pitch curve to be 0 - 50 - 50 - 50 - 100%.
This way, you are basically only going to have 0, 50 and 100 pitch.
When you are at 50, turn the main shaft until the blades are straight left and right.
Then, keeping the rotor head in place, move the blades forwards (or backwards).
At 50%, they should be the same height.
If not, adjust the servo links until they are.

Also, the difference in height should be the same at 0% and 100%, except in opposite directions.

Your swash plate should be level when you are done.

I did that. When I spin the blades at 50, the pitch is 0 but when I look at the blade tips, the height is different by about 3mm. One blade tip is higher than the other.

[oliver1071]

Bent feathering shaft?

[Canadian_Jesus]

It's probably fine. When I zero my pitch one blade always will sit on top of the other. It's just slop in the grip and the flexibility of the blades.

[oliver1071]

Originally Posted by Canadian_Jesus

It's probably fine. When I zero my pitch one blade always will sit on top of the other. It's just slop in the grip and the flexibility of the blades.

+1
Yeah resting micros are sloppy if you see a gap hovering something is wrong.

[heli227]

Originally Posted by Canadian_Jesus

It's probably fine. When I zero my pitch one blade always will sit on top of the other. It's just slop in the grip and the flexibility of the blades.

Actually, I noticed this. It seem that there is slop in the grips and they are not even.

Not sure how to adjust it because pushing on them would bend the feathing shaft...

[GoatRider]

I found I could sometimes twist the blades a bit, and adjust the tracking that way.

[oleost]

Originally Posted by oliver1071

Bent feathering shaft?

1+

Either that or maybe the top links are bent causing them to be different lenght

[stark]

For perfect tracking all these things should be true at the same time at 50% pitch. Turn off the heli after setting 50% pitch so that FBL system is not continuously changing servo position while checking.
1) Swash must be level. Use a swash plate leveler to check this. You can create your own cheapo leveler using a zip tie. You'll have to remove the head to check the swash level. Make sure the top part of swash is not having lot of play. Aluminium swash is a worthwhile upgrade. Adjust the swash level by turning the servo-swash links.
2) Blades must be perfectly straight. Take off the blades and keep them on a glass surface to see if they are straight. You can bend them to make them straight.
3) Blades must be perpendicular to the main shaft ANlD parallel to each other when bent backwards towards the tail boom with the blade grips in the aileron axis. If this doesn't happen you probably have a bent spindle shaft or didn't do 1 & 2 correctly.
4) Blades must not twist in the blade grip and have the same grip tension.

Tip: use the o-ring mod on the (plastic) swash and blade grip to reduce play.

[JonJet]

Originally Posted by heli227

I did that. When I spin the blades at 50, the pitch is 0 but when I look at the blade tips, the height is different by about 3mm. One blade tip is higher than the other.

If you followed Mark's idea and set the pitch curve to 0-50-50-50-100, you have to give it a "grain of salt" depending on whether you go to 50 from 0 or to 50 from 100...there is apt to be an ever-so-slight difference

It may also be your collective stick on the TX not calibrated...what radio are you using?

Blade tracking on the nCPX is not a life-or-death issue, so 3mm at the tips kinda points to bent blades rather than bent grips...unless you've had some serious crashes without Throttle Hold activated in time

If so, you might want to replace the entire head and check the main shaft for splitting

Curious how you discovered that the tracking is ok at 50 when you spin the blades, but when you look at the tips they are off...sounds like a travel issue unless the blades are bent...unless you have a damaged blade grip

[MariaFan]

Originally Posted by JonJet

If you followed Mark's idea and set the pitch curve to 0-50-50-50-100, you have to give it a "grain of salt" depending on whether you go to 50 from 0 or to 50 from 100...there is apt to be an ever-so-slight difference

That's your idea, not mine. I just borrowed it.
I just find it the easiest way to get to 0, 50 and 100.

[JonJet]

Originally Posted by JonJet

If you followed Mark's idea and set the pitch curve to 0-50-50-50-100, you have to give it a "grain of salt" depending on whether you go to 50 from 0 or to 50 from 100...there is apt to be an ever-so-slight difference

Originally Posted by MariaFan

That's your idea, not mine. I just borrowed it.
I just find it the easiest way to get to 0, 50 and 100.

Nah...You help out enough whenever anyone asks too...so you get some credit

I'm sorta tempted to set up an "alternative TH" with a slightly negative 0-stick position to help "hold the heli down" while spooling down at the end of a flight (at least I think the DX9 would do that)

[hellyflyer1]

Originally Posted by JonJet

I'm sorta tempted to set up an "alternative TH" with a slightly negative 0-stick position to help "hold the heli down" while spooling down at the end of a flight (at least I think the DX9 would do that)

Are you trying to stop it from spinning on the ground when after you land the bird. Do let me know if it worked out for you.

As I too am looking at diff options to stop it from spinning on the ground.

[JonJet]

One way is to use O-rings or canopy grommets on the landing gear...

But a slight amount of negative collective will effectively "pin" the heli in place

[hellyflyer1]

Agreed. Thanks