450 Trex 450 pro DFC

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Ricky G

New Member
I bought this heli used. After searching, watching, reading through the forums here I am finally getting close to having the heli flying. This is my first DFC, as I've always flown flybar with the exception of my 130X which was setup with presets for my DX8.

I've recalibrated everything, replaced most of the main components as I wasn't convinced they were up to my standard of a heli. I've checked and checked and I am finally frustrated with it. On to the problem

I have gotten the heli in the air, in normal mode only as I am not confident enough to move into collective. When I lift off, I get high enough to hover , (say 3 ft for the sake of this conversation) and it is fine. The tail is locked in, a little different to hover than a FB heli but I expected it. Here is where it gets strange. The heli will all of the sudden start to rise very slowly and the controls feel very very numb. The only way I've been able to get it down is the hold switch (both times I was lucky enough to have it headed back down and caught it quickly)

I will update with more detail, but I need to do some actual work and then get back to this. For now, here is my heli's info that I know for sure.

Align Trex 450 pro DFC
3GX gyro (unsure the software version, I will have the usb adaptor tomorrow)
align hardware, esc, motor as I'm pretty sure this was a super combo
DX8 radio
2 dsmX satellites

rotors are balanced, main shaft/head/swash/links/bearings/grips/all gears main shaft and rear are new.
Cg is balanced just a little in front of the main shaft
rear rotor direction is good (as it will hover and the tail has not done anything strange the couple times I've hovered it.)

I suspect the gyro version is going to be a big part of my problems, but I want to make sure I haven't missed anything strange. I've talked to several people that give me the "just get a BeastX and be done with it". I didn't spend a fortune on this heli, but I really want to fly it with the align gyro in it for now and upgrade later if I am not truly happy.

I appreciate the help,
Ricky
 
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Ricky G

New Member
I knew I was forgetting some important info.

normal
throttle
0% 40% 65% 85% 100%
pitch
40% 51% 60% 74% 91%

mode 1
throttle
90% 85% 80% 85% 100%
pitch
0% 25% 50% 75% 100%

mode 2
throttle
100% 95% 90% 95% 100%
pitch
0% 25% 50% 75% 100%

swash
ail +40
ele +40
pit +37
exp inh
e ring inh
 
R

Ricky G

New Member
Since I'm asking questions, If you have the option to setup this gyro with two satellites or one sat and a receiver, what would be the option you would choose? I can do it either way but went with two Sat's because it seemed easier.
 
Lee

Lee

Well-Known Member
Well there lies one problem.
As soon as you are at ¼ stick the heli is in positive pitch.
So no matter what you do its probably going to keep climbing unless you reduce throttle to all most nothing.

Try setting up your curves like this for Norm.

Throttle curve 0,40,70,70,70 this will give you a smooth constant power while practicing your hover.
Pitch curve. 45,47,50,75,100. You need a small amount of negative pitch to be able to bring the helicopter down.
It also helps to hold it still when spooling up in windy condition.
If your head is set up correctly (linear curve +- 10º) then 45 & 47 should give you enough negative to work, but not too much that you can slam it into the ground. :D
 
Admiral

Admiral

Well-Known Member
Hi Ricky, two sats are optional on 450 size but required for 500 and upwards, stay with the two and have one with horizontal aerial and the other with vertical for best reception. With the 3GX version 5 is proving to be very stable and has no bad habits that I've found so far.
 
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Ricky G

New Member
I made the adjustment, and it hovers fine. It's strange though because about half way through the pack it's like it got some extra positive pitch and started to climb. I was able to bring it back down but it just felt lazy. I'll be a lot happier when I get the usb adapter tomorrow and I'm able to confirm and update what's going on with the gyro. For now, I'm glad that at least it will hover. Thank you for your help, I've only been lurking on this site for a few days and it's already been invaluable.

- - - Updated - - -

Admiral said:
Hi Ricky, two sats are optional on 450 size but required for 500 and upwards, stay with the two and have one with horizontal aerial and the other with vertical for best reception. With the 3GX version 5 is proving to be very stable and has no bad habits that I've found so far.
Click to expand...

What I was getting at is, does the heli respond/act any better or worse when you use an actual reciever and the link wires instead of the satellites.
 
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Ricky G

New Member
I got my link cable today, found out i had v2.1 software. I just updated the gyro and I'm resetting the 3gx now. Just watching the swash after the update, this should be interesting.
 
R

Ricky G

New Member
set complete, and mystery solved. The aileron and elevator servo have stripped gears, only on a very small place. I've never noticed it before and had 3 successful flights without running into a problem. I'm glad I found it now.

What servo's would you put in to replace the set of 3?
 
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Ricky G

New Member
Well I looked at some nicer servo's but none of the local hobby shops had anything that I was looking for. The servo's that were in the heli were the ds415m. I put DS430M back in it. Hover's like a dream in normal mode. If the rain holds off I will crank it up tomorrow and see what she does.
 
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Ricky G

New Member
Heli hover's reasonably in CP mode, the tail seems to walk a little to the left at hover in 0 wind. I don't really know what to do about it yet, but I'm reading and trying to figure it out. Any input would be awesome.
 
murankar

murankar

Staff member
Okay i am not sure exactly what style you kit is but the concepts are the same. I had that same issue with my last gyro, ZYX-S fbl. I also had that issue with my Assan GA250 head lock gyro, flybared.

First your mechanical setup is off somewhere. While in rate mode check for tail drift. Get the gains for head hold as low as you can without tail wag. Then check for drift, if its drifting then you need to adjust your tail push rod.

If you have to keep giving left rudder then you have a nose right drift. So once you know that then you can go and fix the issue. All i do is after i land i look at the tail servo and give the input that's needed to correct the issue. My servo is mounted on the left air frame with the horn facing the right side. Now if i give left input on the rudder and i see the servo horn move clock wise i know i need to lengthen it. If it moves counter clock wise i know i need to shorten the push rod.

Now that you know what direction you need to adjust make a 2 full turn adjustment and test fly. Remember this will all be done in rate mode. Keep doing this adjustment until you get the nose to drift the other way. Finally after the nose drifts the other direction undo the final adjust by 1 full turn on the linkage, test and then determine if the linkage needs to be backed off by 1 more turn.

The absolute last thing is if you cant stop the drift completely then get the drift to its most stable point. Then using what ever technique you used to 90 the servo use that to make a 1 or 2 point adjustment. Hopefully that will fine tune your tail. Ensure your servo horn stays close to 90.

After your setup is done then head hold should be rock solid.

Sent from my LG-E980 using Forum Runner
 
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Ricky G

New Member
Thanks for the pointer, I will give it a shot tonight. Mine is drifting the nose to the right, so I'll go through it a little at time and get it fixed.
 
murankar

murankar

Staff member
Earlier in my post i mentioned getting the gains set as low as you can in head hold. Scratch that its rate mode. Make sure your rate gains are as low as possible with out wag. That will lock in the tail until you get the mechanical setup dialed in. Yes the tail may still drift but once the setup is nailed it will be solid.

Sent from my LG-E980 using Forum Runner
 
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