swash not level at mid stick

[Darren@Oz]

I've got a HK450 Pro/sport hybrid
it's fitted out with cheapo blue Turnigy servos (apart from tail servo which is a Align)

problem I'm having since replacing the pitch servo (with the exact same make and model as the aileron and elevator) is it wants to pull to the left, which means I have to correct with trim. It then ends up with a distinct lean to the right.

I've adjusted the links and subtrim so that the swash sits level at low and high stick. I've also set the servo arms so they sit 90 deg to the servo body at mid stick ('setup' linear pitch curve)

However when I switch over to my trainer pitch curve (+2-+7deg) at midstick (which I have set at 5 deg pitch) the swash leans slightly one way, which I suspect is causing the problem. But I can't correct this, because I can only adjust low and high stick positions with subtrim.

Could this be the result of cheap servos having unequal travel ?
If better quality servos will sort the problem, I have no problems replacing them (just trying to avoid going through all the swash & pitch setup procedure again unnecessarily....)

[jhamel]

Is this leaning swash issue happening while your FBL unit is in flight mode or setup mode? Just make sure you are setting up in setup mode. Swash leaning on the bench while on flight mode is normal.

[Darren@Oz]

it's a flybar heli

[jgiannakas]

Originally Posted by Darren@Oz

I've got a HK450 Pro/sport hybrid
it's fitted out with cheapo blue Turnigy servos (apart from tail servo which is a Align)

problem I'm having since replacing the pitch servo (with the exact same make and model as the aileron and elevator) is it wants to pull to the left, which means I have to correct with trim. It then ends up with a distinct lean to the right.

I've adjusted the links and subtrim so that the swash sits level at low and high stick. I've also set the servo arms so they sit 90 deg to the servo body at mid stick ('setup' linear pitch curve)

However when I switch over to my trainer pitch curve (+2-+7deg) at midstick (which I have set at 5 deg pitch) the swash leans slightly one way, which I suspect is causing the problem. But I can't correct this, because I can only adjust low and high stick positions with subtrim.

Could this be the result of cheap servos having unequal travel ?
If better quality servos will sort the problem, I have no problems replacing them (just trying to avoid going through all the swash & pitch setup procedure again unnecessarily....)

Try swapping the pitch servo with the elevator servo - that should cure the tilting of the swash as probably the pitch and aileron servo are slightly different speeds. You will have to go through subtrim adjustment to make sure the horns are level to the main shaft, adjust the links from servo to swash until the swash is level at 0 pitch and use the ATV values in your transmitter to take away any interactions between the servos at high and low stick.

Unfortunately I dont think there is an easy way out besides re-doing the mechanical setup...

[Darren@Oz]

ok will try that thanks. Looks like I won't get away with going through all the setup again. I should be able to do it blindfolded soon lol

If I'm going to swap servos around, I might ditch the cheapo turnigy servos for the Align servos I have from another spare parts heli.