Swash will not level at mid stick

[tjames987]

MSH2 BT unit. On the swash leveling and 90 degree horn step i cannot get the swash to level to get 0 degrees of pitch (i have about 4-5 degrees +)

The adjuster is maxed out on the +/- button on the servo that is not leveling. I am hesitant to monkey around with the mechanical links because it is built to manual specs.

I have the Thundertiger E700.

aNY ADVICE??

[xoexoe]

You can remove a servo horn and place it back on a different angle/spline. This is pretty standard to do if you can’t adjust servo subtrim enough.

But to be clear, first you set your horns to be zero degrees at zero pitch using the servo subtrim within your FBL. At this point you stop touching your subtrim, and your swash will likely NOT be level.

Then you turn the links until you get level swash. You must level swash with links, not subtrim, for optimal performance.

After all that, you stop messing with links and move on to tracking/main blade grip links so that blade angle is zero at zero.

It sounds like you might be trying to level the swash with the servo subtrim, which will work, but you won’t have horns perpendicular at zero pitch, so you’ll have slightly uneven range.

[BrainDev]

Originally Posted by tjames987

.... I am hesitant to monkey around with the mechanical links because it is built to manual specs…..

There are no regulations or standards for the mechanics of servos.
Therefore, the position of the main shaft in relation to the fixing points of the servos can change, even considerably, between one brand and another of servos and also between different models of servos of the same brand.
Therefore, the lengths of the links ranging from the servos to the swashplate indicated in the manuals of the eli model kits are only a "general" indications that can only be exact for one and the same model and brand of servo. However, the brand and model of the servos used to make the manual are usually never indicated in the manuals.
The moral of the fairytale: the length of the links can be modified compared to the one indicated in the manuals.

[tjames987]

Thanks for the responses! First I will try the obvious solution which is on the 90 the servo step in the MSH program I will remove the horns and re-center as close to 90 as I can get (this will solve my running out of +/- trim in the MSH step.

Then, if am forced to adjust my links in order to obtain 0 degrees of pitch/level swash at the same time, which links do I adjust? I know the top links are for blade tracking. I guessing I would adjust the vertical links that come off the servo horn???


I am very familiar with the Beastx but this is a whole new learning curve. If I can fight thru it I can enjoy all the nice features such as bailout and telemetry later on.

[Dawiev]

Hi, you can try the following (old-school ) way :

Start by making sure that you are in setup mode when you go to panel # 7 (same for 8). Throttle at 0. Pitch movement will show a large deadband and jump from full negative to 0 to positive. Be sure you have a linear pitch curve, -100, 0, +100

Then get the servo horns at 90 at mid-stick. Manual adjust on the spines as best possible and here you can use trim on panel # 7 to get them as close to level as possible. (always adjust in software, after panel # 5, do not change anything in the TX again)

Now connect the swash and the three servo links, making sure the swash is level. If it needs less than a full turn on the servo link, you can use trim on panel #7 for this. (level swash the priority, rather than servo horn position).

Last the head goes on, blades at 0 pitch at mid-stick - adjust the two swash to head links. If you don't get the same positive and negative pitch you can drop or raise the swash as needed - adjust the three servo links the same amount and recheck level.

[xoexoe]

Originally Posted by Dawiev

Hi, you can try the following (old-school ) way :

Start by making sure that you are in setup mode when you go to panel # 7 (same for 8). Throttle at 0. Pitch movement will show a large deadband and jump from full negative to 0 to positive. Be sure you have a linear pitch curve, -100, 0, +100

Then get the servo horns at 90 at mid-stick. Manual adjust on the spines as best possible and here you can use subtrim to get them as close to level as possible.

Now connect the swash and the three servo links, making sure the swash is level. If it needs less than a full turn on the servo link, you can use subtrim here.

Last the head goes on, blades at 0 pitch at mid-stick - adjust the two swash to head links. If you don't get the same positive and negative pitch you can drop or raise the swash as needed - adjust the three servo links the same amount and recheck level.

I didn't know this as the old school way. What is the new school way?

[ticedoff8]

Then get the servo horns at 90 at mid-stick. Manual adjust on the spines as best possible and here you can use subtrim to get them as close to level as possible.

The term "sub-trim" may imply that you need to adjust something in the transmitter.
Don't do that.
The transmitter's "sub-trim" should be 0 for all servo channels being used for flight controls.

The servo's center point (aka: "sub-trim") should be adjusted in the iKON / Brain setup application for the SVR-1, SVR-2 and SVR-3.
Adjust the servo's "center" so that each of the 3 swash servo arms are at 90*.
You may have to "clock" the servo arm 1 tooth CCW or CW to keep the servo's center less than 20% +/-.


Once these 3 servo's centers are set - do not ever adjust them again
The last part may not be obvious - but in my opinion, it is important.

Then, level the swash at "0 degree" by adjusting the length of 1 or 2 of the 3 links that connect the swash servo's arms to the swash "crown".
Some kits will tell you how long these links are supposed to be. If you carefully measure the length of the 3 links before you install them, you may find that no adjustment is required. But, in fact, you may need to make a minor adjustment to 1 or 2 to get the swash level.

You can adjust the swash's leveling at the maximum and minimum collective points using the servo's "Positive Throw" and "Negative Throw" settings in the iKON / Brain app. Changing these will not affect the servo's center point at mid-stick.


In the end, have a perfectly level swash is not as critical as people make it out to be.
In the "old days" of flybar equipped heli, having a perfectly level swash was more important that in today's flybarless heads and flybarless controllers (like the Brain2 / iKON2).

[PhenixFord]

Originally Posted by xoexoe

I didn't know this as the old school way. What is the new school way?

1) Build your links accurately and according to specs.
2) Center your servos and throw on the horns.
3) Trim out the head and swash by site and look for drifts during maiden.


I'm not experienced enough to do this. But apparently some people are.

[BrainDev]

Then after all this, check blade tracking during hovering at eye level to totally eliminate high frequencies oscillations of the model.

[Dawiev]

Originally Posted by xoexoe

I didn't know this as the old school way. What is the new school way?

Soko Heli Tools: Precise RC Heli Setup

I do have one, it does work, but I can sometimes not be bothered and revert to the tried-and-tested.

[PaoloFCantoni]

Originally Posted by Dawiev

Soko Heli Tools: Precise RC Heli Setup

I do have one, it does work, but I can sometimes not be bothered and revert to the tried-and-tested.

Yes, me too!

On the Protos Maxes and with the Brain/iKon, it's so easy to do.

Paolo