General Servo Centring?

[concodd]

Because the 3 top servo's on the Sab 700 lie flat on there sides is there any need to centre them as there is no need for the servo to do any work on the down side just from level to half way up, and back down again I know what I mean so I hope you guys know.

 

[murankar]

Yes you do. This will allow equal travel in both positive and negative directions. When you go into id1 the servo arm will need to go below mid point to give you negative pitch.

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[concodd]

So once I centre the servo arm, are you saying then I remove the arm and then put it back on the servo at as close to 90 deg as I can?

 

[Slobberdog]

with the servo in centre the servo arm should be on as per your photo

 

[murankar]

Yes. Then you will need to sub trim the servo to get the arm to 90° to the servo body.

Once all that is done you will need to make the appropriate adjustments to get the links to 90° to the servo arms.

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[concodd]

So if I centre my servo and the servo arm ends up in the 3 o clock position I take the servo arm off and place it back in the position, as per the picture, as this is my starting point?

 

[Slobberdog]

take the servo arm off, then centre the servo, then put the arm on as close to the position it is now in,

as the servos lie on their sides then the link 90 deg scenario is the position shown in the picture

 

[Tony]

As stated, the servo arm should be a perfect 90º to the link, or in your helicopters case, just as pictured. It's all about geometry on these helicopters. If you have a perfect 90 on the arm to the link, then you will have perfectly equal travel up and down. As a servo arm moves, it's pivoting around an axis, but hte other end of the linkage is on something that ONLY travels up and down. So the further the servo arm gets away from center, the less travel will be forwarded to the swash. Hope this makes sense. But it's imperative that you center that arm.

 

[concodd]

Thanks Tony, think I got it now.