Titan X-50 Nitro vibration

[fastone93]

Built an X-50 for a buddy of mine, test flew it, has a vibe...

I switched main blades (the stock ones supplied with the kit look kinda suspect), this helped out some, but it still has a vibe that translates into a high frequency side to side vibration on the tip of the vertical fin. It also causes less than desirable gyro performance (Spartan Quark that has been proven on other birds).

So, have any of you guys built one of these and had a vibe problem? Any pointers on where to look first? I am going to balance the main blades and weigh the tail blades etc...

Maybe the torque tube?

Thanks,
Brian

[WessCo]

Make sure the end of the crank shaft isn't touching the start shaft.

[Tomcat-R]

Check all shafts, loose bolts and screws, canopy posts, landing gear screws, gyro foam, blade balance.. Should be fine after that.

[Don S]

For high frequency vibes, check the clutch/fan balance, clutch bell balance, tail rotor assembly balance, and make sure nothing is bent (tail rotor shaft, torque tube shaft, etc).

Check high rpm components for high frequency vibes.

Low vibe stuff comes from the head. Engine tune can also play a part here.

[fastone93]

the whole entire helicopter wobbles...

pick the headspeed up and it seems to stop but I can still see the fuel in the tank almost foaming...

I have changed blades, changed head dampers, etc...

I hear all the time that TT is so much better quality than Align, horsesh!t, this thing is a pile of junk, same ole TT, plastic out the wazooooooooo

I am thankful that I didn't buy this....

[WessCo]

If the headspeed is too low, it'll wobble like you mention. Raise headspeed, wobbles go away?

[Don S]

TT is slipping on their tolerances for sure. The raptor, no shims in the kit. X50, shims included. Then I needed more shims to take some play out.

Does the head appear to wobble on spool down??

[fastone93]

It will wobble any time the headspeed is below insane...

In a hover, I have the throttle curve at 65% power and that is barely above the wobble, even though the whole helicopter wobble is gone, the fuel is still foaming...

when flying, any time you tax the engine and it falls below screaming the wobble will appear, right in the middle of whatever you are doing...

[WessCo]

Do you happen to know what real world rpm 65% throttle is?

All that you've said you've done is change blades. You might have to try harder to find a vibe. Have you checked all of the shafts, like was recommended? Did you make sure the start shaft is not hitting the crank shaft?

[Tomcat-R]

On my R50T after crash wobbles were mainly caused by bent shafts (all of them), loose landing gear and out of balance new blades.

Blades were the worst - really crazy dance on spool up )

[Torresma427]

I had the same problem you have. Did you check the two bolts that hold the head to the main shaft. They were snug but not tight on mine. . I added the second bearing the torque tube.i also replaced the plastic tail blades with carbon fiber ones.i flew it this morning and its very stable now. Check your head speed. I had mine to high. It would shake like crazy. I running 1650 in normal mode. I havnt set idle up yet. Still learning.

Sent from my SAMSUNG-SGH-I717 using Tapatalk 2

[phil m]

have had mine for 3 months now,once tuned properly and geometry set,it runs and flys awesome.os 55hzr/cgy750/futaba servos all around.tt x50 great heli look over everything,loose bolts,wires etc.the problem is right in front of you be patient.

[Don S]

Check engine/fan/clutch runout at all? You need a dial indicator to do this. If the runout is too much (>.002"), you can try mounting the fan/clutch combo in different configurations.

Do a search, Raptor technique also has info on this subject.

[Andy from Sandy]

I maidened my X50F nitro today and it also has foaming fuel. The tail also gives a bit of a wobble but not constant.

On my model the meshing of the autorotation gear and tail drive gear is tight going very tight with no backlash anywhere. When spinning the blades I can hear the gears grinding together at the high spot.

I don't yet which gear is out of shape and to get the boom block out is going to be a nightmare with the way the part is made.

I running 1650 in normal mode.

The gear ratio of 8.5 and running the supplied 53 engine will see a headspeed of 2000 for best power from the engine.

[sengli]

I just got my used X50 flying last week. Mine too had the wobble. Found by lowering my head speed it went away. and flies just fine now. I replaced main shaft, starter shaft, and all the bearing and blocks. Rechecked my blades for balance. Still the only thing that stopped the vertical wobble was lowering the head speed.

[Andy from Sandy]

Due to the design of the boom block I had to take just about every bolt out from the back to the engine mount to allow the frames to be spread to get it out.

I took it apart and put it back together and then assembled the model. The tightness that was in the two gears has now gone.

It was also a good opportunity to check every bolt and nothing had come loose even with the massive vibration being caused by the badly meshing gears.

During the maiden session I ran headspeeds of 1900, 1950 and 2000 and even with the foaming fuel and shudder in the tail the fbl controller was not upset in the cyclic hold of the model.

I just have to wait now for next weekend to see if I really fixed it.

[Don S]

After pulling my YS (maintenance) and replacing with an OS, rechecking blade balance, replacing the main mast (I suspect it is slightly bent, but I really can't see it), and running the tail blades a little tighter in the grips (no side to side action), I am much happier with mine.

Another interesting thing that I noticed is that with a GY520 gyro, a shock (vibe) to the connector block will cause a gyro "hit", so I foam mounted the block.

[Friedrich]

Hallo Don S ,I also have the GY520 gyro on my Titan X50 Torque Tube ,mounted in front on the upper tray. I used the thick foam and damper plate on mine and it also have that slight vibration when I take off.

When I run a little higher rpm the vibration decrease ,but is still there. I also checked my links ,tracking of blades and even balanced them out with tape ,that is all done now but the vibration is still there. Mine shake left and right ,but not too much. I have noticed with the vibrations mine caused ,the thortle came loose on the carburator. Luckely I noticed it before I started it up ,because the throttle was open to its max.

Can you show some pics how you mounted the gyro ,maby it will be the cause of mine too causing the vibrations.

Cheers

Friedrich ,South Africa

[Don S]

Pics. Sorry for the plank, it was close by so I took a shot with it.

Gyro is foam mounted, connector block is foam mounted, gyro wire isn't touching anything. Next time you power up, tap the gyro, tap the block, and jiggle the wire. All these actions will disturb the GY520. Try to isolate all the gyro components from vibration.

[Andy from Sandy]

That top shelf looks an inviting place for a gyro but I don't think it is a very good place. The shelf is not rigid and can flex. It is also quite close to a servo. I admit I have my FBL sensor mounted there for the present time.

Sad to see but it would have been much better had TT continued with the shelf at the back. On most of my models relocating a gyro to the back has fixed pretty much any strange wobbles or wags.