X5 vibration issue

[rholt187]

If anyone can help id really appreciate it. I have a x5 that ive been flying for a while and started to notice a real aggressive vibration. The whole landing gear will shake. I started with blades balanced no issue there. Spindle is new and straight. Head and swash is new. Ive checked the main shaft 5 different times and my buddy checked it not bent. When u spool up the head looks bent . The screw hole in the top of the head wobbles. I dont know what else to do nothing is bent unless the new head is but dont think so cause the whole reason i changed the head because it was doing it before the new parts. No crashes and vibration just gradually got worse.the main shaft bearings are not new but when spooled up with the head off no wobble. Maybe the head on has more weight so it starts to vibrate maybe. Dont know has anyone had this problem. Thanks

[Crashalotjoe]

Do you have any way to log the vibrations (i.e. An FBL with vibration analysis)? This would tell you the frequency of the vibration to help you narrow down the issue.

From experience with X5 vibrations I can say that two areas to look at if it's not the head are motor bearings and torque tube/tail bearings. Also, maybe replace the head dampers if they've done a lot of work.

[mverhorst]

What head do you use?

The very first design wasn't that good and nows to be misdrilled and just overal bad...

Could you post a pic of you head assembly?

[rholt187]

Havnt checked motor or tt bearings yet. But the whole heads been rebuilt. Bearings dampeners thrust bearings .

[rholt187]

Here is the pic of head and swash

[mverhorst]

That's the fomula head, these are supposed to be awesome.

Did the vib just started out of no where?

[anthony1]

what head speed are you running? I noticed with mine(formula head) that while spooling up at a certain point there was a vibration throughout the whole heli which went away as the headspeed increased , it happened near to my chosen headspeed possibly in the 2000 - 2200 range. after lubing the dampeners it went away. cant explain it but it worked for me
Anthony

[rholt187]

The vibration got gradually worse. That was the reason for rebuilding the head with new swash . I think the head speed is around 2300 to 2400

[tonys-heli]

try a couple extra tt bearings..add one in front and one in the back..the align ones go right on.
mine never liked tail blades over 82mm, tried everything. stayed with 82's and went belt.

[rholt187]

Ill try tt bearings idea for sure sounds like a good idea. Do these helis have a vibration issue or no.

[Heli$]

They do. My X5 formula stretch shakes below 2400 rpm with the black dampers.

When I first got the heli over 3 years ago, it was fine. Weird.

[cudaboy_71]

The only time I've had a vibration that made itself worse over time was with getting the front TT crown gear mesh too tight. You absolutely DO need to have the tiniest bit of backlash in them.

If not you put a side load on the radial bearing that supports the vertical shaft. That side load will ruin the bearing and make it notchy and it will cause a severe vibration in the tail frequency (if you're using a vib analyzer)

In my case it manifested with a tail fin shake that got worse and worse until the heli sounded like a meat grinder.

Another spot to easily make a mistake is the two side frame screws that are next to the upper main shaft bearing. During a tear down I mixed up screws and ended up using a screw that went all the way in to the bearing journal. It didn't go far---but far enough to put a little pressure on the bearing. At speed that bearing didn't last long after that. Make sure you don't have a screw riding that bearing.

[rholt187]

Should i up the head speed. Think im running somewhere around 23 or 2350. Got the heli used and flew fine maybe 200 flights later just gradually got worse. Ima rebuild the tail with new bearings and new main shaft bearings and see what happens

[1am7h30n3]

My guess would be main shaft bearings are worn and need replacing.

[DanMcN]

Since this developed due to flight time. Head assembly and shafts do not wear out unless there is an outside factor. The obvious blade angle, tracking, balance CG and arbor.
Check all bearings for notchy-ness, you may not feel or hear while assembled. Disassemble!! Check motor, blade grip (bearings and thrust), main shaft, swashplate, TT (all, including drive shaft) and tail blade grip. Remove the motor pinion and shaft “C” clip, separate the stator and rotor, check the bearings.
Dampers wear, red my give you wobble lower head speed range.
TT gears should not be tightly mated. This will cause premature wear. There should a slight amount of play(gear lash).

[rholt187]

All the bearings looked ok. But replaced anyways sowe will see if it fixs it. Is the gaui motor bearings hard to replace

[Yfbb]

Gaui's first version of the x5 came with bearing blocks that were very poorly designed. The part where the servos mounts and the bearing socket came together was extremely thin on the upper bearing block. They rectified that by significantly beefing those corners.

I had one x5 with the old bearing block that deformed and allowed the bearing to move slightly in the socket causing a wild vibration chase that lasted months. I changed literally every part and the vibes never left until I changed the bearing block.

If you have an earlier version kit I'd recommend double checking. If not, I would check the torque tube bearing spacing, and perhaps and another one. Sometimes when stuff just doesn't work, I just pull off the boom and torque tube altogether and stick a new assembly in.

[DanMcN]

Motor bearings are easy to replace, be careful not to damage the wire windings, use a long punch and knock the bearings out. Installing never tap on the bearing inner races only the outer. If needed you can stack the old bearing over the new and tape it in. Socket of the bearing outer diameter works well.

Bearing choices: "ZZ" are metal sealed, these can be oiled but are not sealed from outside dust and moisture. I prefer the "RS" rubber sealed bearings, these are sealed from outside dust and moisture.

Also motor shafts have a tendency to wear at the pinion end bearing. Check it,,,

Note your washer stack and location. Don't over expand the "C" clip

[Parko29]

Get a new t head block, check the measurements with with your gaui distributer. I have have 2 brand new heads that where an issue for me. I just them replaced under warranty. This caused vibes

[rholt187]

Thanks everyone im to the point now of just buying a new kit . I swear its in the head somehow