Tracking Heli Vibrations

[stickman]

Hello Gurus,

my heli used to fly quite nicely.. but nowadays after many crashes/abuse etc.. developed a horrible vibrations that i cant seem to find the cause.

basically.. slow spool up no vibrations then when headspeed faster then the tail starts vibrating. like really fast one. not tail wag. then the whole heli body vibrates. very obvious cause can see the landing skids vibrate while in the air.

how to go about hunting down the cause of vibrations? got any standard operating procedure for determining cause of heli vibrations?

Thx for any help in advance.

[HotDogBun]

I encountered something very similiar. 2 causes
- taking out the entire rotor head left the main shaft, turn on trottle and the entire tail vibrates, upon closer look, tail blades not tracking well, need to stick piece of tape to balance the tail blades
- the main shaft was only slightly bent, so slight its not to notice by the naked eye, but it contributed greatly to the vibration. Only found out after changing main shaft..

Hope this helps.

[johndyl]

when in doubt, change the feathering and main shafts.. btw roll the shaft on a pc of mirror to chk

[stickman]

heh

both of u are right!

i got a lemon Main shaft from align. after crash i replace with a nib Mainshaft. as it turns out it was probrably very slightly bent, i only can tell when i take out the head like HDB suggested. even then, the mainshaft wobble is VERY VERY little.

anyway just test hover my baby.. she is beautiful again!!
woot!

thx for fast replies guys

[johndyl]

heh

both of u are right!

i got a lemon Main shaft from align. after crash i replace with a nib Mainshaft. as it turns out it was probrably very slightly bent, i only can tell when i take out the head like HDB suggested. even then, the mainshaft wobble is VERY VERY little.

anyway just test hover my baby.. she is beautiful again!!
woot!

thx for fast replies guys

if it is bent nib.. u can bring back to where u bought to change