450 I have a wobble in the heli after upgrades and repairs

[murankar]

I finally got the heli in the sky since the upgrades and main shaft replacement put in. I now have a wobble in the heli. I also have to re setup the gyro and forgot to for this new servo so that could be some of it, the rest not sure. I am hoping the exceed motor is no the root cause if so then I will be waiting till I get home to fly again.

Heres a thought; could the main blades cause it to wobble it they are to loose?

I did the whole hold it on its side and give a quick jerk and they fall to about 45 degrees. the motor is flush tight on the motor mount, links appear to be good, nothing appears bent and I rechecked the tightness of everything.

I just took a pause from this post to set the gyro up. I wont know anything till after I charge the batteries again. Blades balance well, just need to check tracking.

 

[coolgabsi]

What kind of wobble? Tail? I am sorry I don't remember this, but yours is FBL or flybarred?

 

[murankar]

Fly barred, it's not vibrations it's a wobble. At first it was nose to tail then it would wobble in all four directions. When the wind blew it would get a little worse then I would have to set it down. Take off again it was fine. Sorry I do not have video, it was bad enough I was flying today. I guess I am not allowed to fly the rest of time I am here due to missions going on. I get my clearing papers in the AM (wednesday) and I start checking out so I can come home. I will attempt tomorrow if I get the chance.

OH-YEAH, I just went through and oiled some bearings tonight, main blocks, front tail gear (for the belt), all three bearings in the tail, swash and then greased the ball in the swash. It all moves rather freely. I also went and put a drop on the main shaft sleeve and smeared it around the sleeve. I hope maybe I fixed it without knowing it.

 

[Lee]

Normally, unless something is bent, a wobble is due to too low a head speed. Did you change the motor to a lower KV? or smaller pinion?

 

[murankar]

Both, went back to the 3000 kv and 12t pinion. This is only till I get home. I am ordering a new motor shaft today and having it shipped home.

 

[Lee]

3000KV? I would say thats your issue right there. A 450 should be running 3500KV at the least. Mine had 3700s in them. With your set up at 100% throttle you will only get 2600RPM and the recommended is around 2800/3000+

 

[murankar]

Looks like I'll be waiting till I get home. Shame I am gonna be board.

 

[coolgabsi]

Now I have seen that... There has to b a bind in the tail. The brass shims / jackets that sit inside the plastic linkages on the tail slider going to the blade grips ... Both toward the grip and the pitch slide get jammed with loctite and or dust ..

That causes the servi to work twice as hard and then overshoot when the bind loosens at an angle.. Thus the wobble.. That also means that in wind, the tail will wag more as more corrections need to be made..

Either that or the tail push rod from the servi to the tail 90 defree arm is bending somewhere.. Mainly happens if the first support plastic thing for it on the tail boom is sitting too far from the tail boom block or is sliding around causing the tail push rod to bend as the servi will bend it easy.

Let us know

 

[murankar]

When I oiled everything I made sure that everything was running smooth. Took the main tail block out and oiled the bearings for the belt drive gear. I feel that lee found the issue, but won't know for a couple weeks.

If I have time I will try and get over to the auto hobby shop and see if they can help me. If not then when I get home I will have the issue fixed quickly.