General Trex 450 pitch setup?

K

KOS

New Member
OK I bought a pre-owned Trex 450 Pro (I think) any way it is flybarless. Came built but without the gyro and no radio. Got a 3GX and fitted it along with a Spektrum AR610 Rx and a new model Spektrum DX6 Tx. Followed the excellent series of U-tube videos to set up the 3GX(and upgrade to V5). I have done it all with the motor unplugged so far, maybe I am wrong but the setup seems to have a problem. In the DR mode on the 3GX I have 0deg at mid throttle with +12deg full and -12deg at zero as per the instructions however when I initiate the 3GX in normal mode I get 0deg at zero throttle +12deg at mid stick and +24ish deg at full. I guess this cannot be correct but cannot see how to prevent it. Can you help. I am new to the setup of the 3GX and the DX6. I look forward to your replies. Thanks in anticipation.:scratchchin:
 
murankar

murankar

Staff member
The only thing I can think of is that its because its on the bench. The gyros are not sensing movement in the air frame.

Other than that I can't help anymore. One of the die hard 3gx guys will have to help you.

Sent from my LG-E980 using Forum Runner
 
K

KOS

New Member
murankar said:
The only thing I can think of is that its because its on the bench. The gyros are not sensing movement in the air frame.

Other than that I can't help anymore. One of the die hard 3gx guys will have to help you.

Sent from my LG-E980 using Forum Runner
Click to expand...

Thank you for the thought, but I need a bit more brfore I risk launching in case there is something fudementally wrong that I have missed. Thanks again for the response.
 
Graham Lawrie

Graham Lawrie

Well-Known Member
The pitch curve check it is linear and the throttle curve also. I am assuming you followed Tony,s video to the letter? Mechanical 90 servos etc:)

- - - Updated - - -

Ah just had a thought:)
Have you set the maximum and minimum throttle ?
 
Lee

Lee

Well-Known Member
I'm not a 3GX guy, but it looks like you have somehow set up the pitch mechanically to be 0º at low stick.
Can you provide some pictures of the head so we can see if there is a mechanical issue.
Take a picture at low, mid, and high stick.
 
K

KOS

New Member
Followed all the videos as per,(servos at 90deg, swash level etc) with -12/0/+12 at low mid and high stick in 3GX DR mode but when I recycle the system into normal mode for the 3GX I get 0/+12/+something around 24 for low mid and high stick. Don't understand why!
 
stokke

stokke

Well-Known Member
I agree with Kev. Sounds like a curve problem.
Write down your sub trim settings, reset your Tx, then do the DIR setup again.
 
K

KOS

New Member
OK guys, my error I think. Being new to the complete setup game I was trying to make sense on a step by step basis. I should have gone through the complete process for the 3GX rather than looking at the result after just the DR setup stage. Having now gone throught it all up to the flight setup stage it seems to make more sense although I haven't had chance to fly it yet. One other question is C of G. Where should it be? My guess would directly below the rotor head. At present with the battery in the correct place the CofG is about 10mm to the rear. So far back that I cannot correct it with moving the battery forward. Should I add some lead to bring it forward? Thank you for your helpful comments so far.
 
stokke

stokke

Well-Known Member
I wouldn't bother with balancing a 450. Pretty sure it won't matter much in the end due to it's low total weight.
 
murankar

murankar

Staff member
My two 450s balance out so i never had to adjust for it. I still check after switching packs just in case. I am not sure if it is as critical as an airplane.

Sent from my LG-E980 using Forum Runner
 
K

KOS

New Member
OK, the wind dropped and gave me a chance to fly - not good. I am obviously doing something fundamentally wrong although I believe I have set things up as per the series of videos. Only difference is I have v5 loaded on the 3GX not 3.1. Any way attempt to fly, helo wanted to spin CCW as though tail rotor was not working and wanted to roll right. I had training uc fitted so no damage. I think there is still a pitch problem as I still do not get zero pitch at 50% throttle more like +6deg.
I am going to strip it all down and start again. Perhaps my error was buying a 2nd hand helo on ebay that came without the 3gx and then having to buy a 3gx separately. Is there a way to check the servicability of the 3gx? I wonder.
 
Slobberdog

Slobberdog

Well-Known Member
It sounds like you have a couple of your compensations the wrong way around double check those, your pitch curves sound like you are using what align suggest,

Can you post a few pics of your pitch curves or write them down, also your throttle curves as well
 
K

KOS

New Member
Went all the way back to basics. Leveled the swash, set the pitch, checked + and - are =. Worked through all the videos - all working nicely as expected. However, reconnected the motor switched on the Tx and plugged in the power. 3gx OK. but nothing to the motor, and no noises from the ESC. Should there be anny check beeps from the ESC with the motor unplugged as I have had complete silence since I tried to fly and only had noises with the motor connected last time? Any ideas this time?
 
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