T-rex 450L Dominator wobbles

[0veritas0]

Originally Posted by jimmy77611

Are you running 4.0 in the 3GX? If so, you'll need to turn the rudder locking gain slider down from 70 to 50, in the software. Also, look at what the rudder gain value is under the settings display. There you could try setting your radio gain to where the software shows about 35. Should be a good starting point. Your radio and 3GX values won't match. Also, make sure your rudder delay shows 0.

Other than that, make sure the tail pitch slider is butter smooth. I had to redo the plastic links that go from the slider to the blade grips a couple of times because Loctite was getting in there. If it's not smooth, it will wag.

I have no idea what version it is. The manual shows a diagram over 4.0, but I haven't hooked it up to my laptop. I'll do that and check, but if it is 3.2, do I really have to update? I'm not really interested in going thrue the whole setup again.

[jimmy77611]

As far as I know, the dominators should all have 4.0, and since it has a 4.0 sticker, I'm sure that's what you have. You'll definitely have to hook it up to a comp to see what's going on with the settings.

[0veritas0]

I've now connected the 3gx to my comp (thx for the extremely short cable for the dongle, Align). It is v4.0 and I have now decreased the rudder locking gain from 70 to 50. I've set the radio gain to match 35 in the 3gx software. I now got it on 59. Earlier today I set the delay to 0 and left the 3gx to time out after reading about the problems with saving the value. I have not flown since. I have no idea if it was already set to 0 since I pressed the set button when I'd done the adjustment earlier. Neverthenless I checked it in the software and the value is 0. I am gonna work tomorrow but perhaps can take it with me and try it out. Otherwise I'm voting for good weather in the afternoon.

[0veritas0]

I have now hovered and the tail is locked. There is no sign of any wag or hunting at all. I got the throttle curve at 0-15-30-45-60 and I got 2850 rpm at about 75% throttle. That's a headspeed I feel comfortable with so I'm gonna change to a 10T pinion to get the throttle curve higher. The one thing I'm not used to is the amount of pop I get at center stick. I don't think I should bring the RPM down. Is there anything else I could do or should I just get used to it? Maybe this is what happens when I don't follow the recommended pitch and throttle curves?

[jimmy77611]

I'm still breaking in my batteries, but I noticed the pop it has too. I think it's just a matter of getting used to it.

I only fly in idle up with a flat throttle curve. Once I spool up and get in the air, I flip to IU. Even if I'm just hovering around. I don't want to accidentally do a flip or something, and forget I'm not in IU.

To me, electric helis fly better with either governed head speeds or just a flat throttle curve. I think the V shaped curves are kind of old school, and maybe best for nitro. The 5* at mid-stick in "normal" mode, even though recommended in the manual, seems kind of intended for scale flying. I think if you're going to fly any type of 3D, you would want your pitch curves to match from mid stick up, and be 0 at mid stick.

These are merely my opinions, and have served me well on the 13 electric helis that I've owned so far flying sport to mild 3d to hard 3d.

[jimmy77611]

On a side note, I have my "normal" throttle curve at 0-50-65-75-75 and my IU is flat 75%. This way when I flip into IU from a hover, it's not a drastic head speed change.

[devin120]

I'm 0-80-80-80-80-80 in normal and flat 100 in IU. It sounds like a wasp. 10 deg pitch

Everyone I fly with is flat 100 IU and flat curves in normal. Crazy?

Also for 3d anything but 0 Deg pitch at mid stick is a nono.

[markos51]

Dear friend.I have exactly the same wobbling problem with my NEW trex dominator.My wobbly is more than yours so i can not hover.When i tried to hover the heli turned left and right many times and turned on the left on the ground.
Servo gears destroyed.
I tried to solved it many hours with pitch curve throttle curve replacing main shaft.
I was disapointed till i made a goggle search and i found you case.
Please tell me clearly is the main rotor housing the problem?
Is there and guaranty?I bought it for China rc711.com.
It is shame for Align to sell new helis with problems.
Waiting for your help.
THanks.
Markos Greece

[Hemant T]

Guys I'm running my 450L 6S Dominator with Gpro at 2800 Headspeed. It does not seem to have any tail vibrations, no wagging also... its Sold dead center. But some how the body is moving on the alerions quite fast is if there is some vibration. it is more visible on the skids(Wind of like wooble). cant see it going on the elevator tho.

Tried changing the gains on the gyro but no differance.

Any guess what might be causing it & how can i check it or lose it?

I'm some how doubting the Main shaft so have ordered all the 3 shatfs to try them out... Main Shaft, Tail shaft & Feathering shaft. Hope this does the magic. any other suggestions.

[Hemant T]

Guys, when observed closely my main shaft was bent... so changed both main and feathering shafts. The vibes have come down but the wobble on skids is still there. But noticed that when I increase my head RPM to 3000+ the wobble goes away but still can see its coming in intervals.

I checked the heli more closely and noticed the vibes are coming from the end of tail section Only. Have ordered the TT bearings and will assemble two of them and I think it should solve the problem as the vibes are not too bad for putting 3 of them.

[rb30cory]

I am now experiencing a few similar issue, my 450L heli has 600 crashless flights on it. The wobble I can clearly see at the skids, I can make it go away with higher HS, but it comes back as the pack voltage starts to sag later. I have gone through it replaced every bearing besides the motor bearings and the torque tube bearings (I added an additional 1 when I built it). I don't hear any crunchniess in them or feel slop.. This is a nightmare to sort through, from what I can tell the heli seems fine and I begin questions every place there is any movement, however have nothing to compare it to as I cannot quantify ow much is too much..

1. Main Shaft tight vertically
2. Feather shaft tight horizontally
3. blade grips tight but not too tight as I can still move the blades slide to slide without much force required. Shake test they are solid..
4. New bearings in everything but TT and motor - cannot hear/feel play in either
5. Spindle shaft new
6. Dampers new
7. Tail spindle feels like it always has
8. main blades perfectly balanced
9. new tail blades

Left to try is.. considering changing main shaft even though it doesn't appear bent, loosen tail grips a little - right now they are decently tight... now out of ideas

Extremely frustrating issue to say the least... Especially for having essentially flawless performance from July till now.. I hate working on them for things like this.

[Hemant T]

Originally Posted by rb30cory

I am now experiencing a few similar issue, my 450L heli has 600 crashless flights on it. The wobble I can clearly see at the skids, I can make it go away with higher HS, but it comes back as the pack voltage starts to sag later. I have gone through it replaced every bearing besides the motor bearings and the torque tube bearings (I added an additional 1 when I built it). I don't hear any crunchniess in them or feel slop.. This is a nightmare to sort through, from what I can tell the heli seems fine and I begin questions every place there is any movement, however have nothing to compare it to as I cannot quantify ow much is too much..

1. Main Shaft tight vertically
2. Feather shaft tight horizontally
3. blade grips tight but not too tight as I can still move the blades slide to slide without much force required. Shake test they are solid..
4. New bearings in everything but TT and motor - cannot hear/feel play in either
5. Spindle shaft new
6. Dampers new
7. Tail spindle feels like it always has
8. main blades perfectly balanced
9. new tail blades

Left to try is.. considering changing main shaft even though it doesn't appear bent, loosen tail grips a little - right now they are decently tight... now out of ideas

Extremely frustrating issue to say the least... Especially for having essentially flawless performance from July till now.. I hate working on them for things like this.

I would advise try putting 3 bearings, as lot of flyers advise to use 3 & also change the main shaft.
Even slight bent can cause the skids to wobble.

[Miracle Boy]

I'm glad the OP has sorted out the issues he was having and it's now just down to finer tuning.

I bought a new 450L a few months ago. I'm using a Spartan Vortex on it, so can't compare any settings, BUT, When I got mine I had to return the blade grips as they were poorly manufactured and the bearings were a loose fit in the grips and would have created a lot of slop in the head. The replacement grips I got are better, i.e a tighter fit, but they are still not as good as they should be. It might be worth checking out the grip bearing fit in the grips for anyone who is having issues with vibrations in the head.

Align's quality has dropped a bit over the last few years in my opinion, but they do still make good value helis compared the the cost of a lot of kits on the market, many of which cost more to buy, but are no higher in quality of the manufacturing of the parts.

MB

[Hemant T]

Guys, I'm in highly frustrated with the Dominator .
Tried out all ticks and no success

Let me explain... Following items have been changes so far,
- Main Shaft
- Tail Shaft
- Feathering Shaft
- Additional Bearing added, One bearing added at the stock location & other one added 1inch to 2inch from the end of the tail hub.


After all these changes and trial’s, there has no changes in wobble. Please guys give a solution. I've noticed if i spool up the heli with no tail section there is no vibe and even after putting the tail hub without tail blades there is no vibes. As soon as I put the tail blades the Vibes are back... so changes the tail blades also still NO difference
... Pls Help!

[Duikje]

Originally Posted by Hemant T

Guys, I'm in highly frustrated with the Dominator .
Tried out all ticks and no success

Let me explain... Following items have been changes so far,
- Main Shaft
- Tail Shaft
- Feathering Shaft
- Additional Bearing added, One bearing added at the stock location & other one added 1inch to 2inch from the end of the tail hub.


After all these changes and trial’s, there has no changes in wobble. Please guys give a solution. I've noticed if i spool up the heli with no tail section there is no vibe and even after putting the tail hub without tail blades there is no vibes. As soon as I put the tail blades the Vibes are back... so changes the tail blades also still NO difference
... Pls Help!

Take apart the tail section and look for faulty bearings, especially in the blade holders.
If you had a crash before this started to happen, your bladeholders them selfes might be a bit crooked.
The tailblades do exert extra force which might make this problem come out, but kind of hard to see without the blades.
I assume you already have replaced both:
- Torque Tube Rear Drive Gear Set (H45G002XXT)
- 450 Metal Tail Rotor Holder (H45T002XXT)

If you already replaced the shaft H45G002XXT but not the blade holder H45T002XXT, that would be the first thing i would have a look at and replace if you have it.

[Hemant T]

Originally Posted by Duikje

Take apart the tail section and look for faulty bearings, especially in the blade holders.
If you had a crash before this started to happen, your bladeholders them selfes might be a bit crooked.
The tailblades do exert extra force which might make this problem come out, but kind of hard to see without the blades.
I assume you already have replaced both:
- Torque Tube Rear Drive Gear Set (H45G002XXT)
- 450 Metal Tail Rotor Holder (H45T002XXT)

If you already replaced the shaft H45G002XXT but not the blade holder H45T002XXT, that would be the first thing i would have a look at and replace if you have it.

Thanks for a tips Buddy... Really appriciate it!

Its a brand new heli, have not had any crash till now. I've changed the Tail shaft but not the grear set nor the TT. I have both so will change and see.

Right now dont have the Metal Tail Rotor Holder... will try all this before i order this part. Thanks again buddy for the help!

Will keep you posted once made the changes.