HELP! Goblin 500 rotating counterclockwise...

[Marc_RC Heli]

Good morning all! I bought a Goblin 500 used from a fellow flyer here in Angola (Southwestern Africa), and flew it last week with no issues.

A fellow JSCRCC member in Houston sent me this checklist: http://goblin-helicopter.com/mkt/lin...=125&L=237&F=H and since the hell had been flown quite a bit b/y the previous owner I ran down the checklist to be safe.

The main motor belt was tight, and I tightened the tail rotor belt a smidge. The only abnormal thing was that the tail pulley set screw was loose, allowing some play in the tail rotor-head back and forth without the belt/pulley moving, so I tightened it.

Then upon take off this morning, the heli started to rotate counterclockwise and I needed full right rudder stick for it to stop. Fortunately I was able to land safely. Upon moving the rudder on the ground in normal mode, the tail rotor only moved minimally; literally just 5 degrees or so in either direction. Surely it needs to move a lot more. Using trim did nothing.

Any one have something like this happen before, and/or have any ideas on what I should do?

Thanks,
Marc

[Smoggie]

Sounds like the gain might have been reduced way down.

[bad007]

Yes but is the slider centered? Is it binding running out of travel? Does it return to center like it's in rate mode for some reason? Switch assignment for DRs limiting movement. Rather a long list of poss things. What FBL unit and do you fully understand the functionality and setup of it?

[Marc_RC Heli]

Originally Posted by Grumpy_Old_Man

Sounds like the gain might have been reduced way down.

Originally Posted by bad007

Yes but is the slider centered? Is it binding running out of travel? Does it return to center like it's in rate mode for some reason? Switch assignment for DRs limiting movement. Rather a long list of poss things. What FBL unit and do you fully understand the functionality and setup of it?

Thanks for the replies.

I haven't messed with the electronics at all, which is why this is mystifying. I didn use a flathead screwdriver to ensure the servo plugs were all in tightly..could I have messed up one of the wires going into the plug?

The setup is MKS HV servos, Beast X (MACROBEAST) FBL, Talon 90 w/BEC, and the receiver is a Spektrum AR6210. It also a TM1000 Spektrum telemetry unit.

Is the slider centered? On neutral input the is a slight pitch on the tail rotor, but if anything, the direction of the pitch is to where it would counter the heli's natural tendency to rotate countr-cloockwise.

It's not binding/running out of travel; battery disconnected it has free travel in both directions to about 45 degrees.

Switch assignment for DRs limiting movement; apologies...not sure what DR's mean.

Do I fully understand the functionality of the flybar unit? No, I'm a decent intermediate flyer, but in terms of setup and the electronics, pretty much very, very green.

The thing is that it flew perfectly last weekend. The comment on gain being turned down makes sense, but I didn't mess with the setup at all, so how could that have happened?

[Marc_RC Heli]

DR = dual rates... for the rudder the DR is 100% and expo is 25%. The rudder servo is set at "12" (positive number), and the travel is 100.

[bad007]

OK, it's Best to get familiarized with the electronics. Start with the TX. Get to know it. Go through all the settings, look for a screen for DR and Expo and see it there is a switch for auto DRs. DRs allows the user to limit input to tame the heli. The old owner may have inadvertently have altered something in there for the rudder and with a flick of a switch utilizes it.
Next get to know the BX, videos on you tube, Go to BX website read the setup manuals for your version. You may have to go into setup and check everything and start from scratch.
Also if you just tightened the set screw on the tail shaft it mat not be right. there's a dimple or flat spot on the shaft. If it was loose and you just tightened it, it may not be in the proper spot.

[Marc_RC Heli]

Thanks; I'll follow that guidance. Looking at the FBL more closely, its a MicroBeast Plus. I'll study it and the TX to see if there were any alternate switches set up for tail settings. Thanks.

[Jeff Myers]

Tail servo took a dump

[Jeff Myers]

Or u didn't turn ur tail gain from rate to hh

[Marc_RC Heli]

So if you look above, I responded that I hadn't messed with the electronics, and what I meant is that I hadn't intentionally messed with the electronics.
Turns out that if when I connect the battery and "boot-up" the heli, if the bailout switch is set to "bailout", the tail servo does what it was doing. If I then disengage the bailout switch, all goes back to normal. Also, if I connect-battery/boot-up with the bailout disengaged (like I should be doing), no problem at all. I did this repeatedly with consistent results this afternoon, booting up both ways.
I'm very excited to have discovered the root cause of the issue. ; I'm adding this to my pre-every-flight checklist.
And I thank y'all for your input and help in resolving the matter.
However, I now have a spare tail servo on its way from Dallas, but I'm sure it will come in handy in the future.
Thanks!

[bad007]