Fuel Foaming

[robgt]

Good idea, although with no visible signs of vibration on the tail fins, I have my doubts as to that being the cause?
Always worth checking though!

Cheers,
Rob

[Janek]

Bent Tail shaft, or hub ?

[AndersUK]

Make sure your flybar has not been knocked and slightly bent - they are quite soft on the milli. Other than that, main shaft, feathering shaft, I would drop the engine and recheck the runout at the farthest point. Failing any of those I would get those engine bearings checked out. I remember pulling my hair own with foaming once only to eventually find that the bearings were bad on what appeared to be a sweet running engine.

Good luck

Andy

[Steve]

Tail hub is bent - as per previous post, it was of an unknown history.

Have ordered a new one today.

[Steve]

I've just spent an hour or so replacing the bent tail hubs on both my Millenniums with shiny new, straight ones, so here's looking forward to tomorrow to give them a whirl.

However, it was going through my mind as I was doing the changeover, that a bent tail hub is unlikely to cause vibration in the airframe. Provided that the tail shaft is straight, if there is a bit of a bend in the tail hub, then it doesn't affect the balance of the tail rotor, just the tracking of the tail blades.

Having just replaced the bent tail huib in my 90, I had no reason to suspect that it was bent from its flying characteristics - everything was dead smooth and calm with the heli. I only found out it was bent by physically checking it.

So, from recent experience, I would suggest that a slightly bent tail shaft can produce high frequency vibrations throughout the heli, but a slightly bent tail hub is unlikely to show up as a vibration problem at all.

In other words, check them manually regulary as they can easily get twisted just catching the tail blades in and out of the back of the car.