450 Problem with vibration in a Storm 450 rotor head

[Ricardo]

I had problems with some blade grips and change the whole rotor head while spare grips arrive, now there is some vibration just before taking off. It seems to me that perhaps the new main shaft could be wrong...but a new one? Before I change it I will love to know other suggestion.
Thank you.

 

[Tony]

I would check the weight and CG of the blades, then check the main shaft and make sure it's straight. If you forgot a shim in the head somewhere, that can make one blade poke out more than the other (offset) and that will cause a vibration as well.

 

[coolgabsi]

check you blade tracking. and pitch on both blades. The feathering shaft is also something that can be bent... And YES new main shafts come bent sometimes. I have had that happen to me.. check these things before replacing anything. Then the main head block if that is bent at all? is this whole head new or just the main shaft? If the head has been in crashes, it might be the head block...

I know this sounds like i am counting like all major parts. But check your main gear for warp too.. they can be warped from the factory (has happened to me too.. lol ) .. so check that.. if not... i bet someone here will know something.. can you by anychance post a video of your problem ?? It will help a lot!

 

[coolgabsi]

hee hee i think tony and i were typing at the same time.. lol.... do what tony says first.. he might more to the point... haha

 

[Ricardo]

Thank you both for the reply....I already double check the blades for weight, balance, and tracking. I use to balance (dinamic balance) the blades when they arrive. Everything was O.K....but the problem gets worst, now is more obvius that is the main shaft.... And coolgabsi, the whole rotor head it's brand new. Tomorrow I will change the mainshaft and check the feathering shaft too. Anyway I want to change the original gyro and will do everything at the time. I love the HK401B gyros, they are so good and cheap that I use it in all my helis. Before I fixed them with hot glue.
If I don't solve the problem perhaps I make a video for you to help me.

 

[Paulster2]

Thank you both for the reply....I already double check the blades for weight, balance, and tracking. I use to balance (dinamic balance) the blades when they arrive. Everything was O.K....but the problem gets worst, now is more obvius that is the main shaft.... And coolgabsi, the whole rotor head it's brand new. Tomorrow I will change the mainshaft and check the feathering shaft too. Anyway I want to change the original gyro and will do everything at the time. I love the HK401B gyros, they are so good and cheap that I use it in all my helis. Before I fixed them with hot glue.
If I don't solve the problem perhaps I make a video for you to help me.

The video sounds like a great idea ... and I've heard great things about the 401 ... as long as it's glued

 

[Tony]

You have never heard any good things from me on that gyro lol. I purchased two of them, and both were crap IMO. Lots of drift, and never held. But, if you are having luck with them, then that's great. But, I will stick to the GA-250 gyro's by Assan.

 

[Ricardo]

Oh man !!!!!!! I change the brand new main shaft (it was indeed bend) I start the heli and before take off..... it bend another main shaft!!!!!!
Please help !!!!!!

 

[Tony]

Um, it's quite hard to bend a main shaft, and I'm sure that it can't happen with just spooling it up. Take the main shaft and roll it on the glass out of a picture frame. Check all of them before you install them.

 

[Ricardo]

Thank you Tony.
I always check the shafts before installing, and it's bend a lot, not just a little, and at the beginning the heli spin perfectly for a few seconds, after this little period the head went crazy. I check it now, without power and the shaft it's really bend, all the head including servos are moving when I turn the blades. I write to Helipal's Jackie for his opinion.
We will see tomorrow.
Thank you for everything.

 

[Lee]

Your shafts must be made of chocolate if they are bending that easily???

 

[Ricardo]

WELL I THINK I SOLVE THE PROBLEM !!!!!!!!!!!
There was a bolt in the down main shaft block not secure, a little loose, I tighten and apply Loctite, I hope that solve my problem. I will let the glue for 24 hours and then see if that work. LACK OF LOCTITE !!!! seems that I will never learn.
Thanks everybody for the help.

 

[coolgabsi]

lack of loctite causing vibrations..interesting.. let me know what you find out.. was that the jesus bolt??

 

[Tony]

If it was the bolt that holds the head block on, then that will cause a vibration. Hope your problem is fixed.

 

[Ricardo]

Thank you both for your concern, and yes is the bolt that fix everything to the main body thru the main shaft block, and yes it causes first the vibration and second the bend in the main shaft.
I HOPE SO !!!!!!

 

[Ricardo]

YES I MADE IT !!!!!!!!!
I let cure the Loctite (IC-LOC red this time) for 40 hours and voilá....Some minor adjustements and a new gyro (the one you don't like Tony) and the Storm is great, with 0 subtrims. And it looks good with the curly cables that I learned to do in your video.
I just need somebody to fly her !!!!!!

 

[Lee]

Lets see some video of this bird in the air then Ricardo

 

[Ricardo]

Look Lee....The moment I learn to fly I will probably forget to repair and it is very entertained.
I will try to make a short video of my hovering.
By the way, I saw your video with the Chaos 600 and the camera, nice flying and nice video

 

[Lee]

Thanks. Its my favourite heli. So easy to fly.

 

[coolgabsi]

Umm'.... Red loctite. That's gonna be hard to get out.,. Lol if you need to repair it.