ZeXx86 wrote:
So first from all I recommend to carefully verify Tail Mechanics. Some models has this flaw from the beginning unfortunately but it is not common for Align models. But for example old Protos 500 were almost all problematic and for this reason units such as Microbeast were often unusable there. But clearly the problem was at the model, but it was not easy to resolve because of the design and imprecision between parts.
Thank you for taking the time for such a thorough response . I appreciate your input and knowledge.
I am struggling to understand how two different helicopters, with two different spirit GT units. That both seem to be vibration free in flight and fly very well can have such high vibration levels shown only on the y axis while all others are within normal ranges.
I guess it’s possible the 550x has some undiscovered issue , I doubt it but will go through it to make sure .
Unfortunately I have spent many hours on the TB 40 at this point and have come up with nothing. I have dial indicated the main shaft , tail shaft , both feathering shafts , all but the main shaft had absolutely zero run out , with the main shaft having a half a thousandth or .0005 “ which I think is acceptable”. But I happen to have another brand new tb40 kit so I have also systematically swapped out the main shaft , complete tail assembly with no improvements in vibration on the y axis .
I have checked every bearing for roughness or looseness all feel perfectly fine . I have tried many different belt tensions with no change in vibrations, I have clearanced the belt tensioner and idle pulley bracket as the belt was slightly contacting it , no help.
Keep in mind while bench testing the vibration levels were almost zero with only the main grips and tail blades and grips removed, and around 50 with them installed (y axis ) . And raise to about 100-115 with the tail blades installed and spinning with zero pitch , but show more than double that vibration level in flight. Each tail blade with its bolt and nut are within 0.2 grains or 0.013 grams of each other , and the main blades are balanced perfectly on a beam style blade balancer .
At this point I think I’ve done about as much as I can do .
I did remember you had asked for pictures of how the unit was mounted, so I have added those for you to look at to see if I’m missing something there . But the normal things to check like tight wires , no frame contact , one mounting pad etc are all normal . Maybe it’s possible that the fbl mounting plate is somehow transmitting resonant vibrations, or maybe this is all just typical of this align TB40 . Or maybe the spirit unit is over sensitive on the Y axis especially in flight, but that doesn’t sound like it’s the case as it sounds like other helicopters can get the vibrations down around 50 .
Please take a look at the fbl mounting pictures and provide any feedback.
Thank you .