Rotor Blade Vibration

[Decanter]

Hi me again

I'm not trying to tell the more advanced users on this forum how to suck eggs but I discovered this which might be helpful to Beginners like myself............................................ .........

Been a couple a days since I've flown the Blade Cx after its crash, and I had some vibration in the Heli which must have been caused by the rotor system making it more difficult to fly, it turns out it was a hairline crack / fracture in one of the top rotor blades that wasn't obviously damaged in the crash, I didn't replace it at the time as I thought it was fine, I obviously didn't notice it at first as it was very small but it was definitely responsible for the vibration.

At the time of the crash I checked the main shafts to make sure they were ok and the top balance bar, (sorry not sure what its called) was slightly out of balance so that was straightened out when the damage was repaired; I then thought the Heli was Ok after changing one of the rotor blades however it wasn't.

So if all isn't quite well after a tumble and the Heli moves about in an unusual fashion take extra care checking out the rotor blades you never know this may be the reason.

[Snarf]

It's also worth checking blade balance if you have a lot of vibration. I spent a week stripping down my Medevac, changing the inner shaft, changing the outer shaft, running up one motor at a time etc. etc. Turned out when I replaced one of the top blades, they were way out of balance. To check the balance, take the blades off, clip them together (but don't bother with the fixing screws) and then see if they balance at their centre point on a screwdriver shaft (or similar). Swap blades around until you get the best match - but don't mix a top blade with a bottom one

While you are at it, you can also adjust tracking on the top blades by screwing the link between the blades and the flybar in or out until the top blades show no gap when running and viewed side on.

There's hours of simple fun to be had fettling these little contra's while the weather's so foul

[scallybert]

Newbie questions:

What sort of thing would count as "moving about in an unusual fashion" ? [I've got a particular symptom in mind, and I'm wondering if it's damage/set-up/my ineptitude/just how co-axials behave in air currents.]

How easy is it to bend an inner or outer shaft ? What are the symptoms ?

Vibration is irritating, but will it cause any problems ?

The E-Sky rotor blades (Lama, Co-Comanche, etc) pivot around their mounting bolt. Centrifugal force makes the blades take up the correct position. Setting the mounting bolt so the blades move more freely may help with this, and reduce crash damage. Any reason why this might be a bad idea ?