BAD VIBES

[PaulsATOM]

Can anyone help me with this? I don't have a clue what this is saying. Please any help? I'm refering to the SK vibe graph.

Thanks
Paul

[Inkslinginmofo77]

depending on what heli u have thats in the tail rotor area. check the tail rotor shaft to see if its bent. showing fore aft usually means tail rotor shaft

[Xrayted]

Originally Posted by PaulsATOM

Can anyone help me with this? I don't have a clue what this is saying. Please any help? I'm refering to the SK vibe graph.

Thanks
Paul

As stated, it's the tail. I have always found it easiest to test the tail in layers. Start with nothing but the tail shaft installed and do a bench run to check the vibes. If all is well, add the grips, and then eventually the blades. It will become obvious which part of the tail the issue is coming from. You could simply remove the blades as a start, however your blades would need to be really bad out of balance to be the only culprit here.

On another note, your entire baseline vibes elsewhere seem high to me. The entire graph has noise at the 2.5 to 3 vibe level all the way across. This makes me think your FBL mounting is too rigid. My helis spinning parts spikes such as the head and tail are under 3 while in flight, and the rest of the scale is practically zero.

EDIT: I see now that your heli is fairly small, so this is likely why we are seeing higher baseline noise all the way across. Its much harder to isolate the unit from vibrations on smaller models vs larger ones.

[PaulsATOM]

Hey guys thanks for the help. The heli in question is a new Chase 360. I am running KBDD orange plastic tail blades. I will start by taking off the mains and see what happens.

Thanks
paul

[Xrayted]

Originally Posted by PaulsATOM

Hey guys thanks for the help. The heli in question is a new Chase 360. I am running KBDD orange plastic tail blades. I will start by taking off the mains and see what happens.

Thanks
paul

Remove the tail blades. Of course the mains will also need to come off in order to bench test though, but the mains have nothing to do with that big spike.

[Inkslinginmofo77]

REMOVE ALL BLADES!!! Simply put. Fore aft indicate the shaft movement. Since that's the only component that can horizontally throw fore aft frequencies. Like xrayted said, piece by piece. But something witht the tail shaft. If u haven't crashed or wacked your tail then probably a bearing

[PaulsATOM]

Hey took all blades off. Tail is the issue but it is the blades (they are CRAP) Very wicked vibration at higher rpm. You could actually see it. One other thing though. As I spooled her up again to mid rpm range I noticed the swash was like oscillating if thats the right word for it. For a minute I thought the shaft was bent but its actually the swash. Can a bad bearing make the swash move back and forth like that. The shaft is perfect its the actual swash. This heli is brand new just trying to set it up.

Thanks
Paul

[jsbach#1]

I was just gonna say the same thing. That magnitude of a vibration can easily be heard or seen, I can hear and feel a 7 sitting on the bench. The vibe analysis is skookums most amazing feature it really helps me iron everything out.

[Inkslinginmofo77]

yes check the bearings. both main shaft bearings and swash inner bearing. make sure washout linkage or bracket is holding tight too