T-Rex600 Rebuild....

[copterboy]

Ok, so copterboy finally made his choice and converted to the dark side. Had this t-rex sat here for several weeks now, and only just managed to get her up on a new bench. I've pushed in the boom so the torque tube gears bite, but not put any screws in. Oh, and removed the old Voltage Regulator.

Gaz has noticed a slight bend on the flybar, which could have been from shipping. The previous owner said it flew well, and all he did was remove the boom/tail for shipping. That said, one of the frame side's has a pretty decent repair where the canopy mount snapped off, and there is a dent on the pipe, so this heli has definately crashed at one point.

Now I am a complete newb to owning and maintaining a nitro of any form, and I have decided to strip this thing down before I fly it, mainly to gain knowledge of how it's all put together, and take time to learn about the new electronics and engine settings. I just hope I can afford the time and money this will take before the FFFD in 11 wks time!! Maybe the FFFD would be a good time to maiden it with other experienced people around to check it over and listen first? Doubt I'll have the time to get it done and get to the club with Gaz first?

I've also got to decide on a new TX, which until yesterday was only going to be a DX7, but I may now consider a DX8. There are some cheap enough deals for the tx only, as I'm not really interested in the extra channel or telemetry yet.

So my only question for now is where the hell do I start!! I think I'll put the tail boom back out and get started on the frame first, drop the engine and give the bearings a check and clean it up.

Any help from the nitroheads and electronics guru's already here would be apprecited

Thought I would start this thread to keep you updated as I go along, and a place to post my pictures when I get stuck on something, or want to share my joy of some new bling!! lol Just like Jonnys build thread

Cheers

[Jonnyheli]

Well, I'd do a complete strip down and I mean strip down every single piece. Just like it came out of the box.

Don't worry to much about the order you take it apart, but when putting it back together, follow the manual and Bob's build videos.

Organise all the screws into sets by size and type. Same goes for washers, bearings etc. Then you can just pick out the screws/washers/bearings that the manual tell you to use...

Each step in the manual gives a life size picture of the screw or nut or bearing etc and it's units so you should be able to pick out the correct screws easily.

About the engine. There's a set of videos that pinecone made about tunning, starting and fuelling which are really helpful, they will make you feel much for comfortable when you start the heli first time. I'll find them for you later (on my iPad)

Also, read through the OS manual until you have a good idea about what to do and what not to do etc with the engine. Follow the factory settings and tune the engine as necessary from there. The OS manual will explain what your looking for in terms of engine performance (temperature, amount of smoke etc)

If you don't have a 600 manual or OS manual, let me know and I'll find a PDF for you.

By the time you rebuild this heli, you will be ready to start it, trust me.

Jonny

EDIT: here's Pinecone's videos; https://www.helifreak.com/showthread.php?t=115887

[copterboy]

Thanks Jonny, not got the OS manual. Now I know it exists I'm sure I can find it if you CBA.

I'm not saying I'll take my time over it, just that to strip everything down and finding lots of little bits to replace may take time in itself. Nature of the beast and all that.

Well, the heads off now and I'm reading the trex manual about dropping the engine next. Just going to make a fresh brew before I start.

[UPGl2AYDD]

I'd do what you can with what time you got Denis...

Maybe pull the sub assemblies (head, tail and engine) and rip them apart or do very very thorough inspections. The frame and what not I'd just double check it's square, all screws are good and everything is as it should be.

One tip, make sure your boom braces are tight, I mean tight, there cannot be any slack there, they are NECESSARY, they cause some wild oddball quirks in a big model, especially a nitro or flybarless.

Other than that, everything else is common knowledge that you already have. Really there is no major difference between an electric or nitro other than a combustion engine instead of an electric motor and ESC, so don't feel that your at square one. Just set the needles to factory if it's not broken in (cannot remember if it is or isn't) and if it's all good to go as is, leave your needles and go fly, if it makes you feel a bit better give the needle and mixture screw a few clicks rich.

Once you start her up (check the Pinecone videos for a demonstration/tips if you don't know how) and fly her, you'll learn what to look for and listen for, watch some good guides and you'll be on track. Remember, lots of smoke and never sounding pissed off and raspy.

Photos, photos, photos, may very well help us spot things or help you out, plus we luve us some heli porn!

[Jonnyheli]

I'm sure 11 weeks would be long enough for a complete rebuild. But if that's too much then do what Mike said.

If I were you I would put the needles back to the factory settings, that way you will know where you are at with them... If the engine is already broken in then tuning them back up will take 5 minutes. Your looking for a smooth transition between idle and mid speed rpm, the recommended operating temperature and not too much or too little smoke. It might sound like a pain but you will be better off if you know how and when the needles need adjusting.

As Mike said, electric and nitro are almost exactly the same, so just do what you know best for the build. The only learning curve for you here is the whole nitro engine business and really there's not a huge load to learn. A thourough read the the OS manual and Pinecone's videos should cover most if not all you need to know. And just ask here if you need help. I'm not the best person to answer obvisouly, but Tom, Mike, Grant, Gaz and Jerry etc will easily sort you out.

Jonny

[copterboy]

That's just what I need guys....a few tips to get me started and an encouraging little 'it's not so bad' nudge I'll definately keep you updated with some photo's.

I'm going to go for the kind of thing you suggest mike, where I section off each sub-assembly, and replace all screws (already bought with some nice shiny red washers that match the JR servo cases ) and check all the bearings are good (replacing any as I go along).

The guy told me the heli is about two years old, and only flown twice over last 18 months, so the engine is broken in already. I feel like taking it apart to give it a good clean because of the time it's been idel. I'll definately set the needles back to factory settings, and go from there. I will probably be using different fuel than the previous owner to begin with, so that is something I'll lookup tonight. I'll probably replace the fuel line's for good measure too.

So for now I've got this to read....
http://manuals.hobbico.com/osm/50sx-h-manual.pdf
and this....
http://www.rcmodels.org/csm/Rev20man.pdf

Plus I bought a new 2-1, so I need to read that manual too. I maybe back for clarification on a few things later

[Jonnyheli]

If it's the Align 2in1 you've got, the Trex 600 manual will tell you what to do with that

Good luck with it. Keep us updated and with pictures!

Jonny

[jperkosk]

If it's 2 years old, it probably doesn't have Align 2-in-1, as I found out on my brand new 2nd hand 600N. Have already ordered a new 2-in-1 for it from LHS @$80, so it should be cheaper than that on-line...

[copterboy]

Yep, it had a flight tech FT8AVR voltage regulator when I got it so I bought the Align 2-1 a few weeks ago and only opened the box tonight! Cheers for pointing that out Jonny, page 29 of the t-rex manual is exactly the same as the manual that come in the 2-1 box!! I'm wondering is the crocodile clip on the 2-1 positive lead enough to hold it securely to the glow plug? Looking at it, I'm worried about vibes shaking it off in flight, so does anyone change this or is the croc clip good?

I've noticed everything covered in oil, so I feel glad that I've got stuck in and stripped it down. Obviously, this guy didn't polish his pipe anywhere near as well as Mike

When I removed the tail boom again, I noticed it covered in oil. Also noticed 2 screws missing so far, and the bottom muffler screw was a bit difficult to remove, but nothing a quick blast with the soldering iron couldn't fix

I've removed the header tank (which is the red quick uk upgrade mount) and I noticed the screw was bent, and it went up and down as I unscrewed it...Obviously more crash damage!! And I don't have a spare screw that length!!

I'm trying to drop the engine now, and think I removed the wrong 4 screws, still gotthe engine mounts connected!! Also, one of the screws is shorter than the 14mm standard, and another uses a 2mm hex key but is the standard length, and the rest are all 2.5mm!?

This is what I suspected, that there would be alot of minor details to address. At least I'm well stuck in now.

I have to add that I really enjoyed working on it, and really got stuck in. The bigger frame, bigger screws, just bigger everything seemed to make it so much easier to work on.

So what was best to use for cleaning all this oil up? It's even all over the servo wire's!!

[jperkosk]

Can't answer everything, Denis, too green for that, but couple of things are easy:

Don't worry about Align 2-1's crocodile clip. The 2-1 only preheats your glowplug for about 20 sec after you've pushed the ignition button, after that it powers down and the glowplug keeps on glowing only from the combustion heat, so even if it comes off mid-flight (never happened to me, but I'm a slow and gentle flier), the engine operation is not affected.

The engine is much easier to drop when you undo the mounts from the frame, not the engine from the mounts, those screws are PITA to undo. Tom recommends to undo engine from the mounts on one side and mounts from the frame on another to maintain clutch-bell alignment during the reassembly, but I have dropped the motor complete with the mounts for the bearing replacement and never had a problem with alignment later, maybe just gotten lucky.

Spray-bottle of window cleaner + paper towels for cleaning. On this side of the pond Windex is the most popular brand, I spied it on semi-pros at the club's field, and it works well for me as well.

[copterboy]

To late now Jerry, I've dropped it and removed the 4 engine to mount screws!! Made me realise I'd missed 2 of the screws on the fan shroud!!

It appeared the frame mounts were catching on the bottom frame, so I screwed them back in and managed to undo the 4 others on the engoine fairly easily. Maybe I've got a longer hex-driver so the angle of alignment isn't to bad?

I recalled Tom's method, but didn't try it as I wasn't sure if it just applied to the avant, I just wanted to get it done before the night's out. I'll put it back in tomorrow, and try to see if the other methods work for me, but this time I'll make sure all 4 fan shroud screws are removed first Also, the fan shroud is plastic but has the alu. hex frame mount bars inside the moulded part, so should have M3 screw's - 2 of them were self tapping for plastic!!



I've heard of windex, so I'll stock up on some 2m and some nice paper towels for pipe polishing Bed for me now...another new emoticon discovered!!

[Jonnyheli]

Self tappers into metal threads tut. Sounds like that guy didn't bother much with the minor but important details of the build.

I've left the crocodile clip on Denis. As Jerry said, it's only to ignite the glow plug when starting the engine, after that it does nothing. Some people don't even use an onboard glow igniter. They use a glow driver which they remove from the heli once the engine has started. That's what I do for my nitro buggy...

Think of Nitros as mini diesel engines

Jonny

[copterboy]

I decided to do a bit more work, so I've still not gone to bed Removed boom block, undone some of the electronics and then noticed another self tapper in the upper most main shaft bearing block.

Tried to remove it and the head has stripped. Too late to try anything else now, so will come back to it tomorrow with some plumbing grips. This one really is stuck fast. Wouldn't surprise me if he's stuck it in there with CA

Plus when I do finally remove it, will the thread still accept the machine screw's or will the hole be chewed up and need re-tapping?

Bah, enough for one night. Good progress made

[UPGl2AYDD]

A good little 4.8V Battery Dremel does wonders on these helis when you get a screw that will NOT come out. I just grind out a flat head and it always works.

Sounds like some good progress Denis.

As for a pipe polishing tip (LOL): Using an S.O.S pad (which is steel wool and soap combined more or less if you never heard of them) is great, I just grind it around the radius of the pipe (any other way will dull the finish) and it does wonders. A steel-wire rotary bit helps with those stubborn build ups also.

Which reminds me, my heli's have been done for a month or more now and I never posted pictures...

[Tomstoy2]

Take it from my good buddy Mike, he's the official pipe polisher!

[UPGl2AYDD]

Originally Posted by Tomstoy2

Take it from my good buddy Mike, he's the official pipe polisher!

Indeed Tom, [insert snappy comeback here].

[copterboy]

You should do a how to vid of that polishing action Mike. Sounds like you've got that technique perfected

The late night last night made me oversleep for work, but the floor tiles had to be finished today so I can go back and grout tomorrow. Didn't finish work till 7pm, and it's my mates birthday so I'm off out again for a quick couple of pints. Be back later and try and get that screw out!!

All I have to do before I start the re-build stage, is remove the servo's and I'm back to the basic airframe.

Then I'll replace the damaged frame side for a new one I got with the spares. This will mean the new canopy mounts are an equal distance from the frame again, as the repair he did makes it stick out more on one side by about 3-4mm. Next is swap the landing skids from black to white, and swap the skids too. Noticed last night there are no rubber stoppers on the skids!!

Whilst it's apart I can start the cleaning process and replacing the screws I bought weeks ago. Seems fairly easy so far!!

Still got half the engine manual to read, so I'll finish that tonight too. As I think Mike said earlier, I was amazed how much I already knew because of reading the banter on here. So I'm feeling alot more confident about it.

11 weeks!! pah!!

[UPGl2AYDD]

I learned majority of all I know from just back and forth and reading banter - you truly learn what works and what doesn't, what to look out for and all the possible ways you can be screwed or screw up. LOL

Oh, a tip when you strip down your motor, leave the fan/clutch on it until you get the head and piston liner out. You cannot be 100% sure that the liner will come out smoothly or not until you try. With the fan/clutch on you have the ability to turn the crank with little effort, so all you need too do is jam some cloth/rag in the exhaust port into the liner opening and turn the engine over by hand and it should pop that liner up easy as pie and not leave ANY damage. Just crossed my mind when I remembered you were ripping the engine down possibly soon (I would if it has sat for so long, likely gummed up so it may run weird the first few tanks as the carb may be globed up).

I just might have too do a quick tutorial. My pipe was mint when I got it, than that failed RX pack incident ruined it's finish, now it looks nearly new again.

[copterboy]

Cheers for that tip again mike, I'm upto the exploded view in the manual, so I'm just comparing notes to understand what it is your talking about

I understand what your saying though, so will come back to this page once I get to that stage. I can remember reading a warning about causing damage when removing the liner, so I planned to ask when I got to that point!! Saved me the trouble, thanks again

[Jonnyheli]

These little engines are so simple in design. It's amazing how precise all the machining is too. They are such nice things and don't deserve all the bad press they get. People who bash nitro from using them 20 years ago need to see these new engines up close and working.

My engine is still brand new and last time I started it, it literally took like one turn over and it started.

Jonny