3gx R.R.O.D.

[dontascii]

Hi, I have a 450L dom. and I've crashed it twice now. Both times, I get a sudden hard right cyclic without giving any cyclic stick input. The heli goes straight into the ground. The second time, I was compensating with left stick input to try and land safely but then the prob corrected itself and by the time my brain realized what was going on, the heli was on the ground. (From me giving so much left cyclic)

Does this sound like a vibration issue? Is this the same symptoms as the "right roll of death" I've read about with the ar7200bx fbls?

3gx is mounted label-side down right below the main gear. Im on version 3.x of the software.

I'm trying to decide if I should move the 3gx to the back of the heli or if I should ditch the 3gx altogether. (Or if I should troubleshoot other causes)

Thanks in advance!

[jgiannakas]

Originally Posted by dontascii

Hi, I have a 450L dom. and I've crashed it twice now. Both times, I get a sudden hard right cyclic without giving any cyclic stick input. The heli goes straight into the ground. The second time, I was compensating with left stick input to try and land safely but then the prob corrected itself and by the time my brain realized what was going on, the heli was on the ground. (From me giving so much left cyclic)

Does this sound like a vibration issue? Is this the same symptoms as the "right roll of death" I've read about with the ar7200bx fbls?

3gx is mounted label-side down right below the main gear. Im on version 3.x of the software.

I'm trying to decide if I should move the 3gx to the back of the heli or if I should ditch the 3gx altogether. (Or if I should troubleshoot other causes)

Thanks in advance!

Go with version 5, I have it on my 450L and it handles great. It does sound like vibration issues TBH

You have it mounted on the bottom tray, correct? Careful there as the middle aluminium landing gear bracket might come in contact with the 3GX and transfer vibrations to it!

[dontascii]

Originally Posted by jgiannakas

Go with version 5, I have it on my 450L and it handles great. It does sound like vibration issues TBH

You have it mounted on the bottom tray, correct? Careful there as the middle aluminium landing gear bracket might come in contact with the 3GX and transfer vibrations to it!

Yes, I do! It never occurred to me that the landing gear bracket might be the cause of the vibrations! I bet that's it! Looks my 3gx is very close to it, if not touching it.

I think I'll mount it on the other tray, label side up, as soon as my parts arrive in the mail. Having it underneath really makes it hard to go through the setup process and since I'll be upgrading to v5 per your suggestion, it's a perfect time!

Thank you so much! I've said it before and I'll say it again: I don't know where I'd be without this forum, but I know where my heli would be! On the ground.

Thanks again!

[CrashNburn420]

Another thing that helps with the 3gx setup is that make yourself a little switch to turn it on. Makes getting into the DIR setup a lot easier!

Did you spool it up without blades to check for bad vibes?

[RC/DC_5000]

The 3GX death roll is a vibration problem sir. I flew the 3GX for years and know it well. Its probably the most sensitive to vibrations of any FBL system.

Just the tiniest wobble of the torque tube or a poorly centered torque tube gear... and off you go, cyclic rolling/dumping.

The newer FBL systems are much better at handling vibes from bent parts. I flew my Gpro with a torque tube so wobbly, the torque tube itself actually snapped in half before the Gpro did anything weird. The entire time it was vibrating, I was flying away and didn't even know it. Maybe just an occasional skid shake.. but the Gpro kept on flying.

I'll be honest with you... if you're just learning.. I'd just replace the 3GX. It can work and even work really well. But man, its a PITA to master. I mean its a hobby in itself. VBar, IKON, GPro- they all have basically the same setup. Much easier.

I know the 3GX inside and out... but it took a lot of crashing and rebuilding to figure out its quirks. ( and it has a LOT of quirks ).

[dontascii]

Originally Posted by CrashNburn420

Another thing that helps with the 3gx setup is that make yourself a little switch to turn it on. Makes getting into the DIR setup a lot easier!

Did you spool it up without blades to check for bad vibes?

You're right about a switch! I have installed one. No way in hell I was gonna get the 3gx into dir setup mode without it!
There's no vibration issues even with the blades on, at least nothing obvious. I can take off from a hard surface with no problem.

[dontascii]

Originally Posted by RC/DC_5000

The 3GX death roll is a vibration problem sir. I flew the 3GX for years and know it well. Its probably the most sensitive to vibrations of any FBL system.

Just the tiniest wobble of the torque tube or a poorly centered torque tube gear... and off you go, cyclic rolling/dumping.

The newer FBL systems are much better at handling vibes from bent parts. I flew my Gpro with a torque tube so wobbly, the torque tube itself actually snapped in half before the Gpro did anything weird. The entire time it was vibrating, I was flying away and didn't even know it. Maybe just an occasional skid shake.. but the Gpro kept on flying.

I'll be honest with you... if you're just learning.. I'd just replace the 3GX. It can work and even work really well. But man, its a PITA to master. I mean its a hobby in itself. VBar, IKON, GPro- they all have basically the same setup. Much easier.

I know the 3GX inside and out... but it took a lot of crashing and rebuilding to figure out its quirks. ( and it has a LOT of quirks ).

Thanks for the suggestion. I have really been considering an alternative, and your comment is enough for me. I'm tired of crashing because of this issue. I want to crash in style! Lol. Time to go shopping!

Thanks again.

[jgiannakas]

Originally Posted by dontascii

Thanks for the suggestion. I have really been considering an alternative, and your comment is enough for me. I'm tired of crashing because of this issue. I want to crash in style! Lol. Time to go shopping!

Thanks again.

Have you installed a second torque tube bearing as well?

To be honest, I know 3GX has a bad rep but it has worked well for me and I'm a beginner too - just follow these videos and you're set:

3GX Setup Guide Part 1 Mounting & Wiring (10 min 38 sec)