Help! Deflection of control surfaces not even on both sides of the elevator in FT Flyer

[Foamforce]

The pushrods are bending and binding the servo and causing unequal movement of the control surfaces. Even using that ziplock, doesn't straighten the movement of pushrod instead it binds the servo.

Is there any good solution for this?

Sounds like your hinge is too stiff. It should move with very little resistance. It can be stiff if you reinforced with glue but didn’t wipe it out well enough. One way to fix that is to apply new hot glue over the top of the old. The new glue melts the old glue, then you can wipe again. When you wipe, hold the hinge open a little past 90 degrees so that when you wipe, your wiper is in contact with the inside of the hinge. I attached an illustration.

 

[Karthik1130]

Sounds like your hinge is too stiff. It should move with very little resistance. It can be stiff if you reinforced with glue but didn’t wipe it out well enough. One way to fix that is to apply new hot glue over the top of the old. The new glue melts the old glue, then you can wipe again. When you wipe, hold the hinge open a little past 90 degrees so that when you wipe, your wiper is in contact with the inside of the hinge. I attached an illustration.

I checked the interface, there is no hot glue causing any stiffness in hinge. Everytime I am facing issue in making this pushrod and servo with together to move that control surface uniformly on either side. Please help

 

[Foamforce]

I checked the interface, there is no hot glue causing any stiffness in hinge. Everytime I am facing issue in making this pushrod and servo with together to move that control surface uniformly on either side. Please help

Your picture shows your servo at almost full deflection and your pushrod bowed out, but your rudder hasn’t moved. That is caused by a hinge that is too stiff. It could also be that the 45 degree hinge cut isn’t all deep enough. With the pushrod disconnected, can you easily move the rudder? If you shake your plane from side to side, the rudder should flap around freely.

 

[Karthik1130]

Your picture shows your servo at almost full deflection and your pushrod bowed out, but your rudder hasn’t moved. That is caused by a hinge that is too stiff. It could also be that the 45 degree hinge cut isn’t all deep enough. With the pushrod disconnected, can you easily move the rudder? If you shake your plane from side to side, the rudder should flap around freely

Yes the pushrod bows out. The rudder is flapping around freely.When I install ziplock tie the servo binds and gets repaired.
The hinge is definitely not stiff.

 

[Foamforce]

Yes the pushrod bows out. The rudder is flapping around freely.When I install ziplock tie the servo binds and gets repaired.
The hinge is definitely not stiff.

Did you use very weak wire maybe? You should be using music wire, which is stiff. Try gluing and zip tying a skewer to the pushrod wire to stiffen it up.

Or maybe you tightened the nut on the pushrod connector so tight that it can’t rotate at all in the servo arm?

 

[LitterBug]

Did you use very weak wire maybe? You should be using music wire, which is stiff. Try gluing and zip tying a skewer to the pushrod wire to stiffen it up.

Deflection is VERY BAD, especially on long rods. That is why some kits come with the coffee stirers to use a guides. On my FT Cub, I used aluminum tubing almost the whole length of the rods to "fix" the deflection issue after the fact. If they are bending, use stiffer rods like @Foamforce said, or use guide tubes of some sort to control the flex.

 

[Karthik1130]

Did you use very weak wire maybe? You should be using music wire, which is stiff. Try gluing and zip tying a skewer to the pushrod wire to stiffen it up.

Or maybe you tightened the nut on the pushrod connector so tight that it can’t rotate at all in the servo arm?

Thanks a lot, you are right the bevel cut in the hinge is not deep enough. I sanded the edge and now the servo is not binding with the pushrod and I am getting the deflection of 19° in control surface as per FT Delta and FT Flyer throw gauge.

Here have built FT Delta (refer attached image) and to match the CG of plane,the 2S LiPo 850mAh battery is going all the rear end of the powerpod.
Is this battery position right?

 

[Foamforce]

Thanks a lot, you are right the bevel cut in the hinge is not deep enough. I sanded the edge and now the servo is not binding with the pushrod and I am getting the deflection of 19° in control surface as per FT Delta and FT Flyer throw gauge.

Here have built FT Delta (refer attached image) and to match the CG of plane,the 2S LiPo 850mAh battery is going all the rear end of the powerpod.
Is this battery position right?

I built a Delta that had a balance point back there. It just depends on how much weight you put in the nose. As long as it balances on the points given in the design, it doesn’t matter exactly how you got there.

 

[Karthik1130]

The FT Delta maiden flight was a complete success. I balanced the CG exactly as mentioned in the plan.The plane flew well.

But suddenly it started looping on it's own at high altitude in the same altitude,when I was trying to do axial rolls. During that time I couldn't make the wing level to the ground. it started to fall back to ground.

what could be happening here?

 

[quorneng]

If say a battery moved rearward or some part of the airframe broke then un commanded loops could result but I would also look and test very carefully the elevon servos. If one got got stuck "full up" when doing a roll the wings could then only be brought level by putting full up on the other servo however a delta does not fly well in such a condition.