Stiff tail movement

[Anthony Oxlade]

Hi Guys,

I'm just finishing off my e7 build and having a bit of trouble with the tail. Its movement is smooth but stiff and i have figured out that this is due to the tight fit between the Tail bell crank cup and pitch slider ball. Whilst this makes for a very nice slop free tail, it makes the movement much stiffer than i am used to on other helis.

Should i resize the plastic cup until the ball can rotate smoothly inside? At the moment it is a pretty tight fit and does not rotate easily, even with grease.

[Brandon Bartolomucci]

I would also like to hear an opinion on this. My N5c is the same. While my tail holds in the air and moves, I worry about putting extra load on the servo and burning it up. Really all the links are very stiff and one I tried to resize little bits at a time but by the time I got it loose like other helis, it was too loose and slid over the ball & I had to replace it.


Regards,
Brandon Bartolomucci
Sent from my iPhone

[Matt Botos]

Guys,

Here is proper way to make sure your tail bell crank is operating smoothly.

1. Thread M3 bolt into the bell crank and through the bell crank mount but do not fully tighten
2. Thread M3 Nylock onto the end of the bolt
3. Check bell crank for free movement.
      a. If bell crank is too tight loosen bolt.
      b. If bell crank is sloppy, tighten bolt.
4. The M3 Nylock nut is there to lock the bolt from loosening

The trick is to not tighten the M3 bolt all the way and then lock the bolt down with the Nylock nut.

Hope that helps,

Matt

[Anthony Oxlade]

Thanks for the tips Matt. However the stiffness in my tail bell crank is not due to the M3 bolt being too tight. I followed your instructions and the bolt is tightened correctly. The stiffness in my case is due to the friction of the special pivot ball (107-104) in the plastic cup of the tail bell crank.

I measured the outer diameter of the special pivot ball and it is slightly larger than the pivot balls used elsewhere on the heli.

I just want to make sure that i do not need to enlarge the plastic cup to achieve a free moving slider?