Vibration or shakes? CHECK THIS!

[tracknoob]

Originally Posted by ChrisH

The V2 o-rings suck tho ... If I got a V2 I'd replace the front ones with canopy grommets immediately.

Huh. Good tip -- I just assumed they used the canopy grommets, since we already proved they work. I use a whole one on the front two arms, and a half on the back, myself.

[ChrisH]

Originally Posted by tracknoob

Huh. Good tip -- I just assumed they used the canopy grommets, since we already proved they work. I use a whole one on the front two arms, and a half on the back, myself.

No, they used the [much thinner] o-rings from the original mCX ... stupid E-Flite.

The single o-ring on the rear works fine, but as I said ... I'd replace the two front ones with canopy grommets.

[pakk]

This worked for me. Thanks.

But I lost a screw. I lost the one that goes on the back of the servo. Not the screw that holds the servo to the frame.

Where can I get replacements?

[ChrisH]

They may be the smaller screws in the hardware pack, but I'm not positive ... can anyone else confirm?

http://www.horizonhobby.com/products...-mcp-x-BLH3523

[motorbro1470]

i have put grommets on the swash. anyone else got any idea that could be causing the on and off shake?

[RaiDar]

maybe? > https://www.helifreak.com/showthread.php?t=289666

[BunnMan]

I FINALLY made it to the end of this thread! I just brought my mCPX home yesterday after tooling with the mSRX for about a month. SHe's had the shakes since I first fired her up. I haven't disassembled the servos as she's brand new and shouldn't have any corrosion or build up in there yet. I've checked and tried everything else I've run into in reviewing the thread. Feathering shaft is good, I did find a little up/down play in the shaft so I took the gear off and cut the flat a little higher now there's no play there, experimented with tighter/looser blade grips, put full grommets under front swash links, tightenned motor and servo screws, switched to the other set of swash links, re-bound from further than 3' away, levelled swash and set 0 pitch. Setting the pitch was an interesting pursuit...this is where I learned that when setting up the DX6i according to HH specs you have to advance the collective to the extremes and set BOTH ends at 75%. I could get to 0 at center stick but could't figure out why there was a greater differential DOWN than UP...turns out one at 75% and one at 100% will do that, go figure lol.

Anyway, at first she would vibrate occasionally in hover. I haven't tried FFF with this bird yet, skeerd to with the erratic ups, downs, and tail flicks when she's vibrating. Two things that would bring on the shakes without fail were flying outside in a little breeze and running near the end of a pack. When she get's to vibrating everything goes silly, first the tail motor becomes a blur, then she'll start with abrupt pitch changes, then abrupt 90% piros to the right. Flying inside she didn't do it as much but would always start acting up at the end of the pack. A few folks have mentioned low headspeed which could be a factor I guess as I don't hear much difference when I flip to idle up in a hover. I've read the fix for that is to keep flying it until the brushes break in but it's a little dangerous pushing it. So far I've kept crashes fairly minor, nothing broken, nothing lost but that luck aint gonna hold out I'm sure. It honestly seems to be getting worse (more frequent).

I called HH last night and ran through the scenario and they think it's a bad 3 in 1 and are sending a replacement. I'm still trying to stab at it but meeting with the opposite of success at this point. I haven't noticed any servo chatter but I can see and hear that the balde are out of track when the shakes come on. She's a brand spankin new V2 BNF. Any help?

[merch@nt]

Originally Posted by BunnMan

I FINALLY made it to the end of this thread! I just brought my mCPX home yesterday after tooling with the mSRX for about a month. SHe's had the shakes since I first fired her up. I haven't disassembled the servos as she's brand new and shouldn't have any corrosion or build up in there yet. I've checked and tried everything else I've run into in reviewing the thread. Feathering shaft is good, I did find a little up/down play in the shaft so I took the gear off and cut the flat a little higher now there's no play there, experimented with tighter/looser blade grips, put full grommets under front swash links, tightenned motor and servo screws, switched to the other set of swash links, re-bound from further than 3' away, levelled swash and set 0 pitch. Setting the pitch was an interesting pursuit...this is where I learned that when setting up the DX6i according to HH specs you have to advance the collective to the extremes and set BOTH ends at 75%. I could get to 0 at center stick but could't figure out why there was a greater differential DOWN than UP...turns out one at 75% and one at 100% will do that, go figure lol.

Anyway, at first she would vibrate occasionally in hover. I haven't tried FFF with this bird yet, skeerd to with the erratic ups, downs, and tail flicks when she's vibrating. Two things that would bring on the shakes without fail were flying outside in a little breeze and running near the end of a pack. When she get's to vibrating everything goes silly, first the tail motor becomes a blur, then she'll start with abrupt pitch changes, then abrupt 90% piros to the right. Flying inside she didn't do it as much but would always start acting up at the end of the pack. A few folks have mentioned low headspeed which could be a factor I guess as I don't hear much difference when I flip to idle up in a hover. I've read the fix for that is to keep flying it until the brushes break in but it's a little dangerous pushing it. So far I've kept crashes fairly minor, nothing broken, nothing lost but that luck aint gonna hold out I'm sure. It honestly seems to be getting worse (more frequent).

I called HH last night and ran through the scenario and they think it's a bad 3 in 1 and are sending a replacement. I'm still trying to stab at it but meeting with the opposite of success at this point. I haven't noticed any servo chatter but I can see and hear that the balde are out of track when the shakes come on. She's a brand spankin new V2 BNF. Any help?

I just got another brand new mcpx and checked the servos straight away,they were all dirty.
Also one of the wiper arms in the rear servo was bent so i would check all of this.
Another problem is the bearings in the swashplate tend to pop out causing the eratic up and down.

[BunnMan]

I think I might have a bad cell. Disappointing to learn that you had dirty contacts in a brand new heli so I guess I can;t rule that out but I'm still reluctant to disassmble the servos right away and possibly cause more trouble as a few others experienced. I found a little play between the head and shaft as well. It looked like the hole the screw went through was a little larger than the one on the other side when I took the head off. I put a dab of CA on both holes, wiped away the excess and left it to dry to harden up the CF around the holes then re-assembled using the other side. All the play was gone but that didn't help. I was hovering in the living room with all the eratic behavior and a blury tail still. Then a few seconds later I hit LVC. I grabbed my other cell and she flew rock solid, no shakes, no craziness. I also noticed a distinct change in head speed when switching to idle up. As I neard LVC on that cell, I could hear head speed decreasing and the shakes came back. It seems one of my cells may be weak. Granted all this occurred in the living room and not in the back yard where the vibration is more prevalent in the wind. I'm marking both cells and trying to make sense of all this. It is definitely related to head speed for me.

[stablehover]

Whenever I have had the shakes and wobbles it almost always has been from the swash up. I had a slight seperation of the swash that was really hard to detect also I had a rotor head that had elongated the holes where the dampners fit in and that caused all kinds of craziness. A bent or loose feathering shaft has also caused issues for me. I feel your pain because I saw yesterday that you got a new one and the new ones have always fly themost solid. They seem to get quirky as they age. Plus one on the bad batt I have had very strange things happen from bad batts.

[stablehover]

Also that elongated screw hole in the shaft could cause some issues with a loose rotor head or perhaps a cracked shaft itself.

[BunnMan]

Took it outside after the game, bad results. A little vibration in NORMAL. Switched to idle up and the vibes subsided but pitch was unstable. Without moving the collective it would jump up about 4' every few sconds. You could hear the motor labor when the pitch jumped up then smooth out for a second, then labor and jump up another four feet. This was with the stock cell that seemed to be "bad" as it would bring on the shakes even after being topped off on the charger at an indicated voltage of 4.17V. I've got the hypo 250's as well as a warranty replacement 3 in 1 inbound this week...I reckon I'll ring it out once those are in hand.

[AlphaKilo]

Descending spiral of intermittent failures in the controls.

1/4 turn tail
No Aux
No Normal
No either
Won't make take off power
Jumps 4' in a random upward vector

Was reluctant to take apart the servos on a 1 week old bird, but it didn't work anyway. (warranty is good until heli is used the first time)

So, a painstaking saga of 12 tiny screws. Got easier with the 3rd servo. All technique. Took a few hours. All were filthy black on the silver strip.

What a difference! It's actually is flyable again. Looking at the parts, especially that little tan box component. It's on all 4 boards. I'm thinking a distributed gyro system. No primary position data for the servos, from the silver wipers, no feedback for the head stabilization? Flacky servos = flacky gyro?

But, I still think my pitch servo is bad. Still goes from nice hover to a kill switch zoom.

These servos are so small, there is probably not an after market, replacement upgrade? Someone know of one?

[ChrisH]

Originally Posted by AlphaKilo

Descending spiral of intermittent failures in the controls.

1/4 turn tail
No Aux
No Normal
No either
Won't make take off power
Jumps 4' in a random upward vector

Was reluctant to take apart the servos on a 1 week old bird, but it didn't work anyway. (warranty is good until heli is used the first time)

So, a painstaking saga of 12 tiny screws. Got easier with the 3rd servo. All technique. Took a few hours. All were filthy black on the silver strip.

What a difference! It's actually is flyable again. Looking at the parts, especially that little tan box component. It's on all 4 boards. I'm thinking a distributed gyro system. No primary position data for the servos, from the silver wipers, no feedback for the head stabilization? Flacky servos = flacky gyro?

But, I still think my pitch servo is bad. Still goes from nice hover to a kill switch zoom.

These servos are so small, there is probably not an after market, replacement upgrade? Someone know of one?

The tan box is most likely a resistor of some sort, there is no "distributed gyro system" ... it is all on the 3-in-1 board.

No aftermarket servos that I have heard of.

[AlphaKilo]

Well, do you you have any techie info on how this gyro works? I'm a total noob.
For example, 3-1 refers to the 3 servos, or something else?

So far, for me, cleaning the servos is a cure all

[ChrisH]

Originally Posted by AlphaKilo

Well, do you you have any techie info on how this gyro works? I'm a total noob.
For example, 3-1 refers to the 3 servos, or something else?

So far, for me, cleaning the servos is a cure all

3-in-1 = ESCs/gyro/receiver. The board does all 3 functions.

[Andrew73]

Originally Posted by BunnMan

I FINALLY made it to the end of this thread! I just brought my mCPX home yesterday after tooling with the mSRX for about a month. SHe's had the shakes since I first fired her up. I haven't disassembled the servos as she's brand new and shouldn't have any corrosion or build up in there yet. I've checked and tried everything else I've run into in reviewing the thread. Feathering shaft is good, I did find a little up/down play in the shaft so I took the gear off and cut the flat a little higher now there's no play there, experimented with tighter/looser blade grips, put full grommets under front swash links, tightenned motor and servo screws, switched to the other set of swash links, re-bound from further than 3' away, levelled swash and set 0 pitch. Setting the pitch was an interesting pursuit...this is where I learned that when setting up the DX6i according to HH specs you have to advance the collective to the extremes and set BOTH ends at 75%. I could get to 0 at center stick but could't figure out why there was a greater differential DOWN than UP...turns out one at 75% and one at 100% will do that, go figure lol.

Anyway, at first she would vibrate occasionally in hover. I haven't tried FFF with this bird yet, skeerd to with the erratic ups, downs, and tail flicks when she's vibrating. Two things that would bring on the shakes without fail were flying outside in a little breeze and running near the end of a pack. When she get's to vibrating everything goes silly, first the tail motor becomes a blur, then she'll start with abrupt pitch changes, then abrupt 90% piros to the right. Flying inside she didn't do it as much but would always start acting up at the end of the pack. A few folks have mentioned low headspeed which could be a factor I guess as I don't hear much difference when I flip to idle up in a hover. I've read the fix for that is to keep flying it until the brushes break in but it's a little dangerous pushing it. So far I've kept crashes fairly minor, nothing broken, nothing lost but that luck aint gonna hold out I'm sure. It honestly seems to be getting worse (more frequent).

I called HH last night and ran through the scenario and they think it's a bad 3 in 1 and are sending a replacement. I'm still trying to stab at it but meeting with the opposite of success at this point. I haven't noticed any servo chatter but I can see and hear that the balde are out of track when the shakes come on. She's a brand spankin new V2 BNF. Any help?

My new mcpx v2 had intermittent vibrations right out of the box; initially I thought it was related to headspeed or the batteries, or even a problem with the 3-in-1, but it turned out to be a mechanical issue. There was some vertical play in the blades and a tiny amount of horizontal play in the blade grips. I fitted tiny shims between the blades and the grips, and another tiny shim on one side of the spindle to remove any play in the head. I also fitted a MH swash to eliminate the play in the stock one, and replaced the spindle as I'd had a few crashes, and all the vibes are now gone; it's as smooth as silk.

[AlphaKilo]

Yeah, I'm very smooth now. It's difficult to push the drive gear back up on the shaft, but if I turn the heli over and place the top if the head on a hard surface, then I can push firmly with both thumbs on the gear. When you can get to no play in vertical or horizontal of the shaft and blades, that goes very far to end the vibes.

A little tip I found is to put a drop of thread locker into the hole of the spindle shaft before you assemble it. <dooh!!!> I was try to wet the screw. It's hard enough with a dry screw and locker in the hole.

It already threw a blade at me, once. Never again.

[BunnMan]

I replaced the 3 in 1 and things got better but still not eliminated. Every now and again it will still slip into some pretty violent vibes. I tried the servo cleaning, they didn't look to bad to start with. I can see the blade tracking goes to hell when this happens as well. If I twist back and forth at the end of the blades theres definitely some rotational (pitch) play. Looked like the swash was the culprit so I replaced it with a new stock part. Not so much play but there's still some there. My Rakon swash should be here this week, hopefully that does the trick. I've check the feathering shaft and it's straight as an arrow. It's gotta be the plastic swash.

[AlphaKilo]

Just found a blade broken at the trailing edge, root, about 1/3 across the blade.
I was getting a vibration and twitchy tail.