Honey Bee FP vibration

[koenejet]

Hello,
I recently purchased an Esky KOB, Honey Bee FP, Honey Bee CP2 beginners package. The KOB flies great, but I'm haveing issues with the Honey Bee FP that I need some help with. I understand that there will be a little wobble at first untill the blades are pulled straight, and this goes away by about 30% throttle, but by 50% throttle all H#!! breaks loose. It shakes so violently I swear it's about to self distruct.
Here is what I have done so far after following advice from countless forums and videos.
1) removed main blades, ballanced fly bar
2) ran throttle full power (main blades removed), there is no noticable vibration
3) ballanced main blades (dinamicly and staticly) they weigh the same and ballance at
the same point and when on the head, they ballance accross two glasses
4) reinstalled main blades, ran up heli, checked tracking, still get violent shaking after about 50% power

It's weird that untill it starts shaking, it seems very smooth and then all of a sudden it starts without warning.

Here are some things that I am 99% sure of.
1)fly bar is perfectly ballanced
2)main blades are perfectly ballanced
3)fly bar and main blade tracking is perfect
4)rotor shaft is not bent

I am out of ideas. Please help,
Thanks for reading such a long post. (and keep in mind, I am a nubee)
Koenejet

[koenejet]

OK, so I found a "solution" to my problem by searching online and saw how someone added a rotor head stiffiner to the top of the head. Even though there is already one on the bottom of the head, adding one to the top 'should' fix it. I tried it, and it doesn't seem much better. However, I think I may have been inducing the problem. I saw some videos of people weighting there heli down with heavy wrenches accross the skids to do run up tests without it taking off. This is what I was doing when the violent shakes started. But when I pick it up and hold it firmly, it doesn't shake. I am a little familiar with ground resonance (except how to spell it), is this what I am seeing?
I decided to try a short, low hover and as it was lifting off it would very briefly (half a second) shake, and stop, and shake and stop, a couple of times. Once it was about an inch or two off of the ground it seemed smooth.
Can someone PLEASE tell me if this makes any sence or if it's normal.
Thanks in advance for any help and reading my long spelling error riddled question.
Oh, and, should I leave the top stiffiner on, or take it off?
Koenejet

[SurferOfTheSkys]

How about a crack in the frame somewhere?

[Luke Warmwater]

Sounds normal to me.
If you strap a heli down tightly, it will often almost try to beat itself to death....my Belt CP did until I realised that I was fixing it down too tightly. It flew fine.

All helis want to "wobble" a bit as they straighten and balance themselves out. This is often seen as no more than a passing judder and can even go unnoticed....but strap it down and it gets enormously magnified!

A head stiffener is usually thought of as a good idea, although I must admiit, as I use the Xtreme metal head, I never used one....

[SurferOfTheSkys]

Originally Posted by Luke Warmwater

Sounds normal to me.
If you strap a heli down tightly, it will often almost try to beat itself to death....my Belt CP did until I realised that I was fixing it down too tightly. It flew fine.

All helis want to "wobble" a bit as they straighten and balance themselves out. This is often seen as no more than a passing judder and can even go unnoticed....but strap it down and it gets enormously magnified!

A head stiffener is usually thought of as a good idea, although I must admiit, as I use the Xtreme metal head, I never used one....

I used the head stiffener mod to the tune of three stiffener plates with the stock head, liked the difference but also am digging the metal head/BH, metal head took care of that prob, now not to crash! lol