FBL Gyro Bad 3GX....?

BAdair

Member
Has anyone known of or had a 3GX go bad?

My T-rex 500 is now trashed, and it was not me, I would be a little less pissed if I was doing tick tocs, or funnels a foot off the ground and stuck it in but nope. I was just trying to hover after trying to work out issues and it took off ok, hovered for a bit and then went nuts!
Flipping and rolling can't say it was to the same direction either as I was trying to counter act it to get it back down in one piece but it was just too crazy.

I have had good luck with the 3Gx's until now and couldn't believe all the issues most were saying they have had, well now it's my turn I guess.

Some info on the heli and problem.
I bought this heli used off of HF, it is an older esp I think has DS510 plastic servo's, 1600kv motor and a Hobbywing 80amp esc, belt tail setup.
I had been using a CC BEC and a 3s 1000mah to power all electronics, then align 3300mah 6s for motor. 3GX was 2.1, previous owner updated to v3.1.
The heli had always had a weird twitch since I got it as if the elevator gain was to high, in forward flight it would tip and rock forward. I messed with the gain and it didn't change anything from 12 o clock position to all the way down, even tried aileron gain also. I flew it like this for probably 20 flights until I couldn't get it to stop by changing gains and programming, so I thought it might be the belt tail... Spent $115. for a whole TT setup, changed this out, also bound to my JR11x instead of my DX7s and went through all the DIR, rudder, throttle, flight parameter, setups.
Went out to test fly and it didn't seem to have the rocking twitch anymore, it seemed to hover level but in full throttle flight it would have hard elevator forward, almost to the point of going into the ground, I had to hold back on the sticks to keep it up. Swash was all level and even when plugging it in, it initialized and leveled.
I said screw V3.1 took it back to v2.1 to see if that was it, all the setup again, 2.1 doesn't have dampening in the flight parameter settings so I added expo to my radio after DIR setup. (you can use expo right?) Test flew same thing....!
So I then thought well, maybe the extra 3s 1000mah battery and the 3300mah 6s instead of a 2650 is putting it off on balance didn't feel that way holding it but maybe in the air, i don't know figured I would try it and see. So I removed my BEC and plugged the one back in on the Hobbywing ESC & went to fly, spooled up hovered, started moving forward, same thing with the elevator pushing hard forward. I flip it tail over and hovered inverted for a second, flip back over and then all of a sudden it flips on it's own!
From then it seem liked forever fighting it to try and get it down it kept flipping and rolling on me while I was just trying to hover back to a spot to land, it went over my head behind me, I turned around and about the time I thought I had it, flip SMACK!!!

The previous owner did say he crashed it hard about a year before I bought it but he had rebuilt servo's & everything and flown it since.
Could a crash mess a 3GX up where is it intermittent..?

I'm thinking either 3GX is bad,
HobbyWing built in BEC is CRAP,
or a servo went out on me, but I have replaced all gears and tested them on bench.



I am confused on something tho,
You can't use SUB trim after the DIR setup I know that.
So how is it you can use your trim tabs? or can you not?
And Expo, can you use expo on all versions 3GX?
This is the only one I ever have tried it on and I see where it ended up..
My 550 is v2.0 on my Jr11x no expo, my 450 pro is v3.0 on my Jr11x no expo, after trashing the 500 I flew the 450 for 5 batteries just fine.

Any input or Idea's guys?

Thanks


The scrap pile is almost the same as the save pile, think I have a motor to start with...LOL

2014-01-15 15.15.01.jpg
SCRAP
2014-01-15 15.15.11.jpg
KEEP

2014-01-15 15.15.01.jpg

2014-01-15 15.15.11.jpg
 

Tony

Staff member
Yes, you can use Expo.

No, you can not use any trim or subtrim except in DIR mode, and even then, it's ONLY subtrim. Never trim. If it's moving in a hover, then you need to adjust your linkages.

Yes, a hard crash can cause issues like this. I'm thinking you have a bad 3GX. Also, these things HATE vibration! Found that out on my 600 Nitro.

My advice, get the 7200bx or ikon for anything over a 450 size. It sounds like either your elevator servo is cracking out on you, or you need to 86 that 3GX. Now is a great time to upgrade to the 515's if you have the coinage. If you are even going to rebuild this heli. Or just stick with the 550 and 450. Sell what you have of the 500 and thank your stars that those two are working. 2.0 and 3.0 are some horrible firmwares, but if they are working for you, great. I still like the BX much better though. Even with as much testing as I have done to get the 3GX stable.
 

BAdair

Member
I hear ya Tony.
I will more than likely eventually go to the BeastX just can't right now, $240 a pop.. Then again they could save me a lot more than that..
I'm canning that 3gx and just bought another one on ebay for $50 new out of a kit, (yea I know never learn still using 3GX):rolleyes1: lol

Thanks

Brian

- - - Updated - - -

Oh, and a buddy of mine is getting rid of all his 500 stuff he has everything plus a complete bird I'm getting CHEAP from hime with the 515 servos or Savox can't remember.
 

Tony

Staff member
If you can get a kit on the cheap, sweet deal. And I know your pain of the 3GX. It was kicking my ass for the longest time, and I'm still thinking about putting one on my new (er.. old :thinking:) 450 just for giggles of having it the way it was. I remember that thing wanting to tip on the ground (still 2.1), but the thing was stupid stable in the air. Speaking of that, I need to tear the servos apart and check the gears... Ugh, not tonight though. Too busy busting sams B***S over on BrokeAuto.com!!! Everyone should check this out. I have not laughed this much, EVAR!!! lmao. Adults only please. Okay, thread jack done. Good luck on the new 500!
 
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