My Vibe Log--Any Insight?

[dogbreath]

LOG115.SKV

Okay, here's my TRex 550L vibe file. Just hovering in 25mph winds in idle 1 and 2. I'm getting motor vibes (I'm assunming) at 18000, mostly fore/aft. The motor itself has no play, and I can't adjust lash. My guess would be main gear, but it looks/feels fine. Any ideas before I start ordering parts?

thanks, Dan

[georgi UK]

Dan hi, your biggest issue is the SK unit is mounted too stiff. Making it difficult to zone in on the vibes. Agreed there is a motor drone going on there, and also a possible TT issue?



My approach would be softer mount the unit, run a bench motor only log and look at the KDE adjustable motor mounting upgrade to get perfect meshing. Followed by a flight log to see where it's at,,,,,,

cheers, georgi.

[Luvmyhelis]

Get rid of the stock align motor mount plate. Georgi nailed it.... You will still have a tighter mesh on one side and sloppy mesh on the other though even with an adjustable mount.

Stock align molded gears are never ever round. They have a high (farther from gear center) tight spot against the pinion, wobble, then a low (lots of slop, closer to gear center) gear rotation every time around. You can ignore this, but will always see vibes here, which accelerate gear and bearing wear throughout. On 550s and up we also rotate the plastic gears on the aluminum main hubs to get as close as possible to a better concentric gear set. But I have tossed dozens of plastic gears that were just garbage through the years that were just way too far out.
Personally, I only use cnc milled Kde gears on my aligns now, also their adjustable motor plates.

[dogbreath]

Thanks Georgi & LMH. I'm working on the parts etc. This bird goes to a buddy so I wanted it to fly right--I'm building an eXo 500 for me. Dan

[WI_Hedgehog]

Thanks guys, love your insight, always learning new ways to spot problems quickly, and solve them efficiently.