600 My T-Rex 550 Rebuild

PLANETGETLOW

PLANETGETLOW

Banned
I maidedend my 550 this weekend and wow it was buttery smooth smooth. I wanted to do some flips amd rolls but just hovered and flew out a pack. Ill create another thread for it. It has some pretty unique features that make it a tank.
 
Heliman450

Heliman450

Well-Known Member
Hi all, another maiden with exactly the same result but on the servo end of the rod rather than the tail end :pissed-off: :banghead: . Fortunately, once again no damage and before the ball link let go it was looking good for a stable hover about 1m from the ground.

I've been back to the manuals and they don't show the centre-2-centre (C-2-C) dimensions for the carbon tail with the links only for the metal rod.
I confirmed the actual sizes as being 640mm including the threaded ends and 626mm for the rod itself. The ends measure out at 2.05mm diameter. The correct ball links are contained in pack #H60071A.

So tomorrow morning back to the workshop. If anyone can give me their C-2-C dimension, I'll test that out first.
 
Heliman450

Heliman450

Well-Known Member
PLANETGETLOW said:
I maidedend my 550 this weekend and wow it was buttery smooth smooth. I wanted to do some flips amd rolls but just hovered and flew out a pack. Ill create another thread for it. It has some pretty unique features that make it a tank.
Click to expand...

So when am I going to see this 550 'tank' then?

- - - Updated - - -

Hi all, ready to go again tomorrow morning, fingers crossed.
 
Heliman450

Heliman450

Well-Known Member
D.O.G. said:
Nothing wrong with failure as long as you learn from it.
Click to expand...

Hi D.O.G., only problem is that I'm not sure what I'm 'learning' at the moment. The problem isn't the ball links, yes, I believe that one can inadvertently use one, which is too big but the root cause of my problem lies with my tail setup. This is made more difficult as the servo is buried inside the body of the heli on the 550 (maybe others, too). I've never learnt gynaecology in my years so far, so it just isn't possible to see the servo during the setup process. I've entered a big change in the Spirit Pro settings basically out of instinct rather than from knowledge gained despite trying to find the answer here and in my books and instruction manuals.

Let you all know what I've done after today's test.
 
Heliman450

Heliman450

Well-Known Member
Hi all, I'm pleased to say that a successful maiden flight took place. Everything was videoed, so after a few initial 'hops' to prove that the tail was sound enough (and to trim up the pitch curve a little) I was able to take a couple of minutes of hover to test it out better to use up the battery. Off to charge up some more flight batteries :biggrin1:

I'll publish the video later today or early tomorrow.
 
Heliman450

Heliman450

Well-Known Member
Here it is, at last!

[video=youtube_share;PNyAIAGJDU8]https://youtu.be/PNyAIAGJDU8[/video]

Just over 2 minutes from a total of 2mins 28secs, so almost uncut. You can't quite see but she's got no 'clothes' (canopy) on.
 
trainrider06

trainrider06

Active Member
She looks good Phil! nOt quite sure the issue you were having on the sevo ball links but looks like shes ready freddy!!!
 
Smoggie

Smoggie

Well-Known Member
Looking good Phil, she looked a bit twitchy at the start but maybe that was just nerves after not flying for a while? I hope your weather holds out for long enough for you to get some more flights in.
 
Heliman450

Heliman450

Well-Known Member
Hi guys,

I agree that she's looking a bit twitchy, but to start with I was only giving the minimum of input to see how it settled out. My thinking is that the gyro needs around 20-30 seconds of flight to crunch the calculations that make up the PID control inputs. I normally give the heli a 40-50 seconds hover at the start of a battery during which, it settles itself out and afterwards is always steady. I've got no idea how long the memory is inside the unit. Another thing I've noticed is that once I've tested the gyro control directions it's much better not to do it every time as it only 'confuses' the gyro.

Maybe you've got a view on it, Steve?

After my flight this morning, the tail is a bit twitchy and I did some changes to the gyro settings but it didn't improve the problem. Maybe it just needs some more adjusting so that's something for another day now.

Rodney,

The ball links were coming off the ends of the push rod due to a combination of not being screwed in enough and with the tail settings through the Spirit Pro. I figured that something was wrong so causing the extra force that was required to pull them out. I lined up the tail rotor by entering a negative value in the tail rudder alignment until it came level. Unfortunately, it's not possible to see the actual rotor arm as it's buried inside the body when installed. I did check it beforehand without the servo mounted and it looked centred, so is probably off centre now. This servo arm has never been removed since I got the heli so shouldn't have changed (unless someone can tell me why it may be different).

The threaded ends of the carbon rod are only 7mm long and there's no forward/backward adjustment available on the servo mounting, so the only adjustment available is via the Spirit Pro after maximising the length of the push rod, which is now 672mm centre-to-centre. Any more risks the ball link coming off as it's not screwed right in at the moment.

Looking forward to the feedback but can't respond until later or tomorrow.
 
Heliman450

Heliman450

Well-Known Member
Smoggie said:
Looking good Phil, she looked a bit twitchy at the start but maybe that was just nerves after not flying for a while? I hope your weather holds out for long enough for you to get some more flights in.
Click to expand...

I have to confess to having a few 'butterflies', but not exactly nerves after what is over a month since its last flight. At the moment, I think that it is more responsive, but that really could be a lack of practice on my part.

Weather is looking very good for the next week or so albeit a bit cooler than a week ago. Can't say that's a negative thing as it's just about perfect for an old Englishman :biggrin1:
 
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