Another tail issue?

[flymustangs]

Maybe I'm just overthinking the tail on this thing, but now I've noticed another problem. With the heli on the ground, spooled up before take off, there is a bit of high speed twitch in the tail. It's not constant. It comes and goes. See the short video below:



Another odd thing is that the twitch is gone after a flight with it sitting on the ground spooled up. Maybe something temperature dependent?

I was doing some tic-tocs today and was able to bog the heli! I don't recall being able to do that before. I'm using the stock setup with Gens Ace packs set up for 14S total. The heli only has about 15 flights on it so the batteries are basically new. I don't know if this is related to the twitch or not. Maybe something going on with the governor/ESC?

[flymustangs]

OK, the twitch is really hard to see in that video even when viewed in the large format, but you can definitely hear a noise change (speed change?)

[Jays200]

I'd be very interested to know what your vbar log looks like, particularly if it contains any "governor signal glitches" or "loss of governor signal.

Any chance of uploading a copy of the log please.

Regards,

Jayson

[jamin_00]

If it is try disabling the Vbar gov and see if it goes away?

[MrMel]

Check the log as posted, if need be if you have it try a Hyperion phase sensor.
Those YGE cables are long and VERY easy to get interference on (both from external and internal on the ESC and the battery power cables)

I've seen a few that putting on a simple external phase sensor cured it all.

[jamin_00]

Forgive my ignorance here, but whats the external phase sensor and where does it go. Never looked or seen one

[MrMel]

Originally Posted by jamin_00

Forgive my ignorance here, but whats the external phase sensor and where does it go. Never looked or seen one

http://www.hyperion-eu.com/products/.../HP-EM2-TACHBL

[flymustangs]

Sorry for the delay, but here is the log. Nothing out of the ordinary that I see. The second Governor ON at 10:33 and Governor Mode Stop at 10:55 was when I spooled it back up after an auto to see if the twitch was still there after the flight.

I do have a Hyperion senser that I can try.

[jamin_00]

So where would that phase sensor plug in, running with the YGE XXtreme ESC and Vbar??

Sorry to hijack

[MrMel]

single cable goes to a motor cable, servo connector goes to SENSOR II port.

[jamin_00]

Originally Posted by MrMel

single cable goes to a motor cable, servo connector goes to SENSOR II port.

Thanks, where does the lead that comes off the ESC that would have gone in that port go? nowhere just tied up out off the way?

[MrMel]

Exactly.

[jamin_00]

Originally Posted by MrMel

Exactly.

Thanks

[flymustangs]

If I'm using a Hyperion external sensor do I need to tie the RX and main grounds together?

[flymustangs]

I was checking some ground continuity so I knew how all this should work. While doing so, I noticed the RPM sensor plug from the ESC wasn't completely inserted into the vbar. It wasn't hot glued, but it is now! I'm sure hoping that's the problem. It's going to be raining all day to day so no testing.

[flymustangs]

I got a flight on it today and it appears the sensor plug may have been the problem. That does make me wonder why there wasn't anything in the log to indicate that. I understand you would want a buffer so there isn't a rash of false alarms, but it seems like it may not be sensitive enough.

[MrMel]

Problem is if RPM just differ it could be "valid", it does not see that as a problem, only if it's "outside the possible range" it call it a glitch.

[flymustangs]

Yea, that makes sense now. If it's missing a pulse every now and then because of a bad connection it would show as a change in speed instead of a LOS.

I'm still wondering about one other thing. There is a noise in flight that doesn't seem quite normal. It may very well be on this heli since it has the combined belt/torque tube drive. There are no mechanical issues that I can find and it flies fine. I think I notice it the most when I'm coming back on collective after the disc has been unloaded, like in a rapid descent.

I've watch videos of other Xxtremes flying, but most of those are constant 3D so the blade noise would drown this out. I'll try to get some video, but I don't know if it will show very well what I'm talking about.

[MrMel]

a) take a picture of the drivetrain from the side/check alignment.
b) check pinion alignment
c) check main shaft collar (no movement up/down)

Spray everything with silicon spray.

Usually works for me

[flymustangs]

Thanks again for the help Fredrik. I'll go over these and see if anything comes up or it solves the problem.