Blade 400 3D vibration problem

[Billybaxter]

New Blade 400 straight out of box. All tests OK. Spin up produced expected shudder while blades settled, then vibration continued while upping revs. The shudder is enough to make the tail dance around quite a bit. When spinning down the shudder is worst at very low revs - just before blades stop - nearly enough to tip chopper.
Gyro seems fine. Blade tracking looks perfect. No obvious bent bits. What is a good sequence of elimination? Should I remove paddles / paddle bars / blades? first?
Quite new to all this - Had a CX2 for a couple of months.
Cheers

[widower]

It sounds to me like the blades are too tight. There's different suggestions for how tight the blades should be. I have them just tight enough that when I hold the heli vertical, the blades don't fall. A slight jerk, and they fall.

[dieselracer]

New Blade 400 straight out of box. All tests OK. Spin up produced expected shudder while blades settled, then vibration continued while upping revs. The shudder is enough to make the tail dance around quite a bit. When spinning down the shudder is worst at very low revs - just before blades stop - nearly enough to tip chopper.
Gyro seems fine. Blade tracking looks perfect. No obvious bent bits. What is a good sequence of elimination? Should I remove paddles / paddle bars / blades? first?
Quite new to all this - Had a CX2 for a couple of months.
Cheers
Check the boom supports. We had one out of the box with a vibration. It was the boom supports. they were not glued in to the inserts.

[Billybaxter]

Thanks for your input guys. After some testing and surfing the forums I worked out it was a bent main shaft. Just replaced it today and 90% of the vibration has gone. Just some minor tuning now. Cheers.

[bobyjimmie]

Did you need to buy the shaft yourself or did your LHS replace it since it was fresh outta the box?

[Slyster]

There is a b400 sub forum under this one.. might be better to join us there!