Vibration re sent

T

treff

Active Member
I have resent this vid again this time on youtube so hopefully it will work. I have changed quite a few things most except the blades which are to be honest damaged on the ends but would this cause this much vibration. Cheers
Vibration 1 - YouTube
 
Tony

Tony

Staff member
The only thing that I really noticed in that video was the ball on the tail looked like it was moving a bit. Almost like the vertical stab was loose. Is that the vibration you were talking about, or is there something else that I didn't pick up?
 
DAL2855

DAL2855

Banned
Man I wish I could fly half that good! There's no way I could hold the bird there that long! It always seems to get away from me!

- - - Updated - - -

Tony, I also noticed it vibrating back and forth as well as the up and down vibs too!
 
Tony

Tony

Staff member
You said up and down, and that got me looking at the disk a little closer. I see what you are talking about.

Treff, when you hold the tip of teh blade, what is the up and down movement? I know on my HK450GT it's about an inch and it scares the crap out of me. Looks like maybe the feathering shaft bolts are not tight, or the dampers are completely worn out. I will be trying some things on my heli here shortly to help remove this play and if it works, I will post it up on here in the forum.
 
Derek

Derek

Well-Known Member
I was gonna say the feathering shaft bolts, too. is the flybar bent at all? is the flybar centered?

Nice hovering, treff! I'm glad to see that you are still trying.
 
DAL2855

DAL2855

Banned
Tony, I have found that using O-Rings in the dampers are much more effective in reducing the up and down movement than the original dampers. I had bought an O-Ring kit on ebay to have some for my Nitro engines and had to replace some dampers in one of my heads and didn't have the original replacements so I decided to try these regular O-Rings and they worked perfectly and absolutely no slop at all in the head! Will have to get you an actual size on them measurement wise.
 
T

treff

Active Member
HI Tony and DAL2855. Thanks for the replies and suggestions. I have checked feathering shaft, it is a new one I replaced last week. The moment on the dampers is about and inch give or take, very hard to measure. I have now replaced the main blades with Align seconds to see what happens. I am having trouble getting the tracking right the vibs are so bad you can not see which blade is running high or low, it all just a blur so I think something really amiss in the head. I have removed and checked the main shaft and to me it looks true. I have run the heli up and looked down the shaft from the top and there are no wobbles or movement so I am really at a loss.
 
Karubah

Karubah

Member
Treff, that vibration in the tail looks very fast. Just a thought from a VERY inexperienced bloke but could you have a slight bend in the tail blade shaft? It seemed to vibrate up and down as well as side ways. No doubt you have already checked this. Nice flying buy the way.
 
DAL2855

DAL2855

Banned
if the blades have that much up and down play, right there is the root of the problem Treff! Sounds like the dampers aren't doing their job! Or maybe the blades aren't tight enough in the blade grips. How tight are you tightening them?
 
T

treff

Active Member
Thanks mountaindewdude76. Yes from a newbie point of view every thing looks straight and in line and the flybar is centred. It's very strange. I am probably missing something along the line. I have to go out today so all the testing will be tomorrow. I have a new flybar so I will change that also. It can not do any harm. Thanks.
 
DAL2855

DAL2855

Banned
Yeah Karubah, I didn't even think about the tail shaft being bent causing that vib like that, but it's definitely a huge possibility! Might wanna check that too Treff! I would pull the main blades off, and the entire tail head and spool the bird up to flight rpm and watch the tail shaft and see if it wobbles at all!
 
Tony

Tony

Staff member
Take the main shaft and feathering shaft and roll them on the glass of a picture frame. That will tell you if they are bent. Looking by eye can prove false.

DAL, I ordered some 80# Align stock dampers and they are a million times stronger than the crap silicone soft stuff that it came with. I also ordered the DFC dampers which are effectively the same plastic as the tail block, very hard. I will be trying both of these.

Treff, I have a video series under the DX6i link in the articles section. It's the DX6i & CCPM setup guide. In there, I show a complete helicopter setup from start to finish. Have a look if you get time.

Make sure yoru flybar paddles are directly inline with the flybar cage. And also make sure the flybar rod as well as the paddles are EXACTLY the same length form the cage on each side.

We will get you through it bro. This is just a hobby, don't take it too seriously. All in good fun.
 
Tony

Tony

Staff member
It's easier to just eyeball them to the flybar cage. I don't think I have ever used a pitch gauge on the paddles.
 
Tony

Tony

Staff member
Yeah, as long as your cage, mixing and washout arms are all level at mid stick, that could work.
 
DAL2855

DAL2855

Banned
yeah that was what the video showed to do, do all your arm leveling first, then when installing the paddles, ensure they are same distance from the cage to each paddle, then level with the pitch gauge!
 
Slobberdog

Slobberdog

Well-Known Member
Hi treff nice flying there mate, but I had the same movement on the old one I had, does your head have o ring dampers or a tube like damper, if the latter try putting Align V2 dampers or KBDD dampers on it, if its the o ring type get the align Se dampers as they seem to be a bit harder. The clone dampers seem to be a bit soft
 
Lee

Lee

Well-Known Member
Its def a tracking issue Treff. As the heli spools up, there is a point where the blades stop and you can see them wobble up and down. If the feather shaft is straight, mainshaft is straight, the dampers are solid, and the flybar is lined up and straight, then check the head block. I bent one in a crash on my 450. With the blades off, look down on the top of the head at the screw in the head button. As you spool up does the screw wobble or stay in the centre? If it wobbles, and all your other parts are true, then it could be the head block.
 
T

treff

Active Member
Many thanks to all for the suggestions. I have checked the shaft and changed the feathering shaft to an Align make. I have also changed main blades to Align and also the tail slider to Align. The helicopter as not had a serious crash more tip overs but it's difficult to tell there's a lot of force behind these moving parts. The main shaft does not wobble but the head block does quite badly. I tightened up the jesus bolt quite tight to help this but always thought is was not right. Also I was very surprised at the old tail slider wearing with just a few short flights so this may indicate something wrong in the tail section.. I will put all suggestions into practice and report back. It must be something I am missing. Thanks again guys very much appreciated. Cheers
 
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