More vibe log comments?

[npomeroy]

The vibration levels were less than 1.0 most of the time so probably no remedy is needed. Nevertheless I'd appreciate comments.
This is for a TRex 550 stretched to 600, with a 3-bladed head, on a test-bed for flight trials before going into an AS350 fuselage.
Here's the build thread with the page showing the test rig.
https://www.helifreak.com/showthread...12#post6716112
HS govenerned to 1400. Tail ratio is 4.5. Gearing is 11.8 : 1 with an Align 750MX - 450kV motor.

[A VIKING]

Nice...vibe levels look great to me.
It will change somewhat after you move off the test platform as I am sure it's dampening out some of the vibes but it looks great for now.
Nice looking ship, good job!

[npomeroy]

The vibe levels are not so different here on a later flight where the HS was governed to 1500, but there are some higher ones. Do you think any of these are due to the CC governor zapping the motor on/off? You can see the ESC log here https://www.helifreak.com/showthread...=595869&page=5 and I've posted the actual file over in the Castle forum.

[Luvmyhelis]

Originally Posted by npomeroy

The vibe levels are not so different here on a later flight where the HS was governed to 1500, but there are some higher ones. Do you think any of these are due to the CC governor zapping the motor on/off? You can see the ESC log here https://www.helifreak.com/showthread...=595869&page=5 and I've posted the actual file over in the Castle forum.

Nope, the up down motor vibes are from harmonics related to the timing pwm settings. I have seen far far worse on flying ships, most notably out of Kontronik's. A very slight tail imbalance, ( TT issue if this is TT equipped?) and some very minor side to side vibes out of the head, which may be due to main shaft wobble if this is a two bearing main shaft support. Or even damps or the blade design, even some slight slop in one or more of the grips. Tracking that has a very slight deviation under load? Notice it sends harmonics through to the others?

At these levels. None of this, nothing. Is remotely worrisome unless you want to chase the rabbit?

[npomeroy]

Thanks LMHs. It has a TT tail, and there were similar tail frequ. vibes with different blades. It has a longer-than-standard main shaft with 2 bearings (T-Rex 550 mechanics). It has a three bladed head and I just noticed a bit of end play in two of the three grips. The head needs to come off soon to insert scale bellows so I may strip it down. I can't see the point in chasing any other rabbits.

Nelson