Vibrations...

[J-Heli]

I'm still trying to to figure out if I have a vibration, and if I do, how to fix it. In a day or two I'll try to get a video of the tail and see what you guys think. I'm visiting with my Grandparents, so I don't have access to video equipment until Thursday afternoon. It looks as if there is a high frequency vibration in the tail, but I'm not positive. I fixed the pinion to main gear mesh, which I thought could've been the cause of the vibration, but I'm not positive it's totally gone. The other possibility is that something is bent, but other than a few hard landings with training gear, I've got no idea how something could've gotten bent to begin with, unless it was bent right from the factory. Just looking for some guidance.

BTW, has anyone else had any vibration problems with the belt driven tail right out of the box?

[small.planes]

My tail fin 'buzzes' side to side, you can see it in a tail in hover. The head runs ok, no vibes there, and it doesnt seem to affect the flying, so Ive not attempted to track it down.

Dave

[MonsterMaxx]

I spun mine up for the first time last night (no blades.) There's quite a bit of vibration at low rpm, but it dissappears as things spool up and gets very smooth.

Looks to me like it could be coming from the crown gear (it has a slight wobble) but with the crown gear on global backorder there's not much I can do right yet.

[J-Heli]

I spun mine up for the first time last night (no blades.) There's quite a bit of vibration at low rpm, but it dissappears as things spool up and gets very smooth.

This is exactly what mine does. I wasn't sure if the viration was going away or just becoming more high frequency as the RPM increased. I'll still post a video so you guys can take a look, but this is encouraging! :fly

Looks to me like it could be coming from the crown gear (it has a slight wobble) but with the crown gear on global backorder there's not much I can do right yet.

When you say crown gear, do you mean the main gear because my main gear has a slight wobble? I've replaced it once, but it looks like a manufacturing defect in the gear.

Thanks for the help.

[MonsterMaxx]

I have the shaft drive version, it has a 'crown gear' for engaging with the motor.

[GeneP]

I spun mine up for the first time last night (no blades.) There's quite a bit of vibration at low rpm, but it dissappears as things spool up and gets very smooth.

It looks as if the Helista may have a mission. We have a spin-up with no no blades. Is that a flogging or just a simple thumbscrews??:shock:

[SurfCity]

My guess is that it's your blades. Try a spinup with no tail blades -- not to full throttle, just to the vibe zone -- and check.

[MonsterMaxx]

It looks as if the Helista may have a mission. We have a spin-up with no no blades. Is that a flogging or just a simple thumbscrews??:shock:
What's the BFD? This is on 2s and I didn't give it 100% throttle. Just checking things out before adding all the additional complexity of having blades on there.
Doesn't seem to have done any harm.
In reality, with modern brushless systems you can't really overspeed them anyway, particularly when not pushing the envelope on volts.
Yea, I can understand your complaint if I'm at the top of the volts range and wail the stick to WOT. But with a gentile spin up on minimum voltage what's the harm?

[Jetleaf]

It looks as if the Helista may have a mission. We have a spin-up with no no blades. Is that a flogging or just a simple thumbscrews??:shock:
That would depend on how fast. Idleup? I don't want to be near it. 20% - 40% not a biggy.

[Jetleaf]

Cuzz, did it start all of a sudden? Right after anything was changed? Have you checked bearings for smoothness? I recently had two brand new main shaft bearings that felt like they had sand in them. Does everything spin freely? All screws tight? Have you tried running the belt looser or tighter to see if that helped or hindered? What are your curves? Blade balancing? Flybar and paddles equidistant from the cage? Check that the belt isn't crossed over itself inside the boom. Check that the belt isn't rubbing the inside of the tailbox. These are just things I would be checking. You definitely want to cure the vibration even if you can still fly it like that, the fin should not be buzzing. That is still vibration and it is just wearing out things quicker when you fly it like that.

[Jetleaf]

I spun mine up for the first time last night (no blades.) There's quite a bit of vibration at low rpm, but it dissappears as things spool up and gets very smooth.

Looks to me like it could be coming from the crown gear (it has a slight wobble) but with the crown gear on global backorder there's not much I can do right yet.


Hey Maxx, try putting a second set screw in the crown gear. There is already a hole there for one. That removed a lot of the wobble from mine.

[Gr4yb3ard]

'Cuzz,

Check the boom for any bends, If memory serves, Pete had that problem once....

Gr4

[Fudd]

Also check the bearings are tight in the tail case, they tend to work loose in the cf plates. I had the same problem and only noticed it when I pulled it apart to fit the SD upgrade

[J-Heli]

'Cuzz,

Check the boom for any bends, If memory serves, Pete had that problem once....

Gr4

Will do. I remember the thread Pete started about that.

Also check the bearings are tight in the tail case, they tend to work loose in the cf plates. I had the same problem and only noticed it when I pulled it apart to fit the SD upgrade

I have the MH tail upgrade so I shouldn't have that problem, but I'll check over the tail really well.

[J-Heli]

My guess is that it's your blades. Try a spinup with no tail blades -- not to full throttle, just to the vibe zone -- and check.

Could be... I'll check this out also.
Cuzz, did it start all of a sudden? Right after anything was changed? Have you checked bearings for smoothness? I recently had two brand new main shaft bearings that felt like they had sand in them. Does everything spin freely? All screws tight? Have you tried running the belt looser or tighter to see if that helped or hindered? What are your curves? Blade balancing? Flybar and paddles equidistant from the cage? Check that the belt isn't crossed over itself inside the boom. Check that the belt isn't rubbing the inside of the tailbox. These are just things I would be checking. You definitely want to cure the vibration even if you can still fly it like that, the fin should not be buzzing. That is still vibration and it is just wearing out things quicker when you fly it like that.

I'll check everything you mentioned in this post. Sounds like I should be able to figure it out with all these great suggestions.

If I've exhausted all these ideas and it's still no better, I'll post that video just so you guys can take a look for yourself.

Thanks again for all the ideas.

[J-Heli]

I haven't had real chance to look over the heli, but in a real quick look-over, I noticed that the tail pitch slider arm was loose. Really loose! Could this have been the problem?

[Jetleaf]

I doubt that was causing the vibration. It was probably loosened by the vibration.

[Buzzkill]

I had a lot of vibration on my belt drive tail. Turned out to be a bent rotor grip screw. Just like the main rotor grip screw only on the tail and a LOT smaller. Only a very very slight bend barely noticably by eye but enough to cause the tail fin to vibe at a super high rate.

[J-Heli]

I had a lot of vibration on my belt drive tail. Turned out to be a bent rotor grip screw. Just like the main rotor grip screw only on the tail and a LOT smaller. Only a very very slight bend barely noticably by eye but enough to cause the tail fin to vibe at a super high rate.

Thanks for the other suggestion. I've got to change the tail blades after some tests today anyway so I'll check it out.

I find this odd. When I first start to spool it up it's as smooth as silk, then at about 30% throttle a slight vibration visible from the vertical tail fin arises. Then as soon as the heli gets light on it's skids, the vibration goes away and everything is as smooth as silk again. Then when I spool down, when the RPMs get REALLY low, the tail boom bobbs up and down slowly until the main rotor blades stop turning. I've never seen anything like it :dontknow. I'll keep looking into it.

[crabfu]

with any vibration problems... which often throws off the gyro as well, I always say.... check the CF tail plates with the bearing, they tend to get loose and grind a nice big hole in the CF, causing all sorts of strange vibration, wag and drift problems.

-Crabfu

[Jetleaf]

I agree Crabfu. The tail box has to be tight or it causes all sorts of issues. I was playing with spare parts the other night and discovered you can really make the stock tailbox very tight and smooth by just doubling the side plates. You have to adjust a couple of the screw lengths and it bolts together very nicely. And you probably have side plates laying around so it's economical too.

[psindrup]

Thanks for the other suggestion. I've got to change the tail blades after some tests today anyway so I'll check it out.

I find this odd. When I first start to spool it up it's as smooth as silk, then at about 30% throttle a slight vibration visible from the vertical tail fin arises. Then as soon as the heli gets light on it's skids, the vibration goes away and everything is as smooth as silk again. Then when I spool down, when the RPMs get REALLY low, the tail boom bobbs up and down slowly until the main rotor blades stop turning. I've never seen anything like it :dontknow. I'll keep looking into it.

How about just flying it? :smokin:

I think my tail vibration was due to a slightly bent tail boom that caused the tail belt to "touch itself" - but I am not absolutely sure.

I now run the stock CF tail side plates, with the rest of the tail parts from MicroHeli, and it seems to work just fine.

Peter

[rotorhead58d]

How about just flying it? :smokin:

I think my tail vibration was due to a slightly bent tail boom that caused the tail belt to "touch itself" - but I am not absolutely sure.

I now run the stock CF tail side plates, with the rest of the tail parts from MicroHeli, and it seems to work just fine.

Peter

me too peter. same set up for me. no problemo

[psindrup]

me too peter. same set up for me. no problemo

I got the idea from you, Rotorhead. :thumbup:

Peter

PS: What is it you and Gray up to? :YeaBaby:

Peter

[rotorhead58d]

I got the idea from you, Rotorhead. :thumbup:

Peter

PS: What is it you and Gray are up to? :YeaBaby:

Peter


(insert evil laugh here) you'll see.....