Break Down/Rebuild or Leave it

[DMJAX]

Hey All,

First time posting here, so hello to you all.

If you were to buy/receive a used CP heli (name brand) with approximately 25 hours flight time, in "excellent" condition, which also has some upgrade parts (servo's), would you first:
1) Break it down completely, replacing all hardware, upgrade any parts and rebuild?
or
2) Break it down and rebuild using existing parts (replacing only what was found to be bad)
or
3) Leave it as is and try to fly it first (after full preflight, walk around checks of course)
or
4) Other

(Note: First CP Heli, familiar/fly FP and Quads)

[ArchmageAU]

Originally Posted by DMJAX

Hey All,

First time posting here, so hello to you all.

If you were to buy/receive a used CP heli (name brand) with approximately 25 hours flight time, in "excellent" condition, which also has some upgrade parts (servo's), would you first:
1) Break it down completely, replacing all hardware, upgrade any parts and rebuild?
or
2) Break it down and rebuild using existing parts (replacing only what was found to be bad)
or
3) Leave it as is and try to fly it first (after full preflight, walk around checks of course)
or
4) Other

(Note: First CP Heli, familiar/fly FP and Quads)

If you trust the builder AND have seen it fly in person, then 3), otherwise 2). Make sure your first flights are on docile settings and are like maidens so that you can see (and understand) what is going on.

If 3), you need to ensure all screws that should have loctite have loctite and that servos are good, mesh is right, no cracks, bearings good, etc....

Both my big 2nd hand helis I saw fly before purchase and I trust the competence of the builders. Both have performed flawlessly.

[Ron_R]

I would do 2), hands down.

Take it apart, inspect all components, replace what seems to be worn/broken, clean it well, loctite and CA what needs to be and viola.

Why worry about what might happen on spool up or risk a failure midflight if you can avoid it by cleaning her up a bit?

[Big Air]

+1 on #2. You will also know how to disassemble and reassemble it when the inevitable happens...............

[Felix the cat]

# 2 For sure.

# 3 Can be considered, but it'll be risky.

Since it will be your first CP. Hmmmm make sure you set it up appropriately and have at it On either 2 or 3.
Buy extra main shafts, main gears, featherings and blades.

[Imzzaudae]

What helicopter?

I'm a fan of complete re setup of transmitter functions.
No Surprises!

I always remove the main shaft and gears.
I always clean main and Swash bearings.

Re Lubricate with silicone lubricant.
On a 400 size helicopter I use 7,000 weight silicone differential fluid.
micro I use 10 weight silicone RC truck shock oil.

Remove feathering shaft and service bearings!

Balance Blades is a must.

R/C Heli Tutorial #6 Lubricants (13 min 55 sec)

You must give the tail rotor system a good inspection!
Make sure the gyro is working and the rudder input operates in the correct direction.

Do a from the ground up transmitter setup!
If it's a fly bar helicopter?

RC Helicopter flybar & pitch set-up (7 min 29 sec)

[DMJAX]

It's a 450 size, not a clone and has some upgrade parts (I'm waiting until I actually get it to provide more info once I see everything).

So far, #2 has it, and was my first choice as well, though I'd still like to see it spool up just to see what it does (nothing off the ground), see if it shakes/wobbles itself to death or seems smooth and responsive...still deciding though so thanks EVERYONE for your inputs.

Should be here tomorrow or Wednesday, once I get it I'll send pictures and depending on what I see during initial look over "preflight" inspection I'll make final decision.

[Imzzaudae]

First Collective pitch helicopter ?

Is the helicopter a Trex 450?

What transmitter are you planning on flying the new helicopter with.

Any chance you have Real Flight or Phoenix flight simulator?
Can you fly the helicopters in the simulator?

[Ah Clem]

#2 plus complete re-set up.

[DMJAX]

Well, got here as promised. I took it out of the box, and gave her a good once (twice) look over, looks to be in really good shape, but I provided plenty of pics for you all to provide thoughts.

I am going to break it down, check each part, lub/oil as needed and rebuild (#2). I'm not in any hurry as I fly my 200SR X and Quad all the time, the 200SR X is giving me good flight lessons, and I also have the ClearView Sim which I'm flying the CP Pro model now (I can hover that pretty well but taking baby steps as it were).

One thing I did do after "pre-flighting" her was to make sure my DX6I Binds correctly, which it did and I spun up the engines just enough to get a sense everything was working; all controls responded as expected, no wobble or vibrations at a good rotor speed, but didn't get off the ground...Just a quick spin up, spin down and back into the house.

I'd welcome any thoughts or suggestions. I'm not sure where to start the dismantle but will do some more googling...

See Images here: https://imageshack.com/a/gHdz/1

[jml79]

That's a blade 450X. It has a lot of plastic. You shouldn't need to completely tear it apart. Plastic holds screws well and remember that it doesn't mix with loctite. Make sure your metal to metal screws have loctite and check all of the bearings and shafts. Basically head, shaft, drive system and tail need to be closely inspected. The frame screws just have to be checked that they are tight and not stripped.

Then watch everything you can on the beastx and the ar7200 so you can learn how to set it up.

[DMJAX]

Understand the Loctite/Plastic, just initial observation on the Metal-2-Metal.

So, appears that a couple of the swash linkages are a bit bent (haven't pulled them off yet but visually), so going to pull them and inspect. I have complete new replacement parts if required. I'm hoping the setup info out there will make this somewhat painless but it has to be done.

I'm also looking at the swash/main shaft. Not sure but the swash seems a bit sloppy with some play in all directions, but I believe it's the linkages as they definitely have a bit of slop (hence why I'm replacing them).

[Imzzaudae]

Very nice helicopter!

The helicopter looks in pretty nice shape!
Look at the motor. You must be careful that you do not let the battery
rub on the motor bell. It will set fire to the helicopter!

I'd pull one blade and spin the feathering shaft.
Pull the main blades.
Put a finger on each blade grip and spin the feathering shaft. If you don't feel a warble.
Lubricate the helicopter. Check the tail Belt is tight enough and bench test the thing.

Check it over with a fine tooth comb!
If it was mine. I'd do the main shaft bearings, pull the head apart.
Replace the rubber dampers with new dampers very well lubricated with 3,000 silicone
weight silicone differential fluid. Re assemble and threadlock the feathering shaft assembly.

Function everything!
Aileron and Elevator and Rudder are working correctly.
Walk away and re inspect the helicopter with fresh eyes.

Do the same with the transmitter settings!
Make sure you put it down, come back tomorrow and re check it!
You will be surprised how often you find setup errors that can easily cost you a helicopter!



You need to number 1 - 2 - 3 - 4t those Lipo with a marker that won't come off.

Discharge them and recharge!!
Do not trust them!
Don't fly the batteries until you have tested that they will not LVC on you mid flight!
If a Lipo does not last 6 min.
Give it to someone running a car, it's not worth the expense of a helicopter crash!

Hope you enjoy your new helicopter!
Ron

Remember this helicopter will not bounce, it disintegrates on contact!

[DMJAX]

Pretty much tore it down already. Spindle looks good, main shaft as well. Had a bent linkage on the Swash, main gear had some bad teeth and the tail servo linkage was bent...repalcing them all (replacing all head linkages with new ones just to be safe, some had a bit more play then I would expect).

Have new main/tail blades coming, some other parts as well but starting to put her back together...looking forward to leveling the swash, setting it up and then spinning it up...that's going to take some time and effort...8-)

I'm replacing the Dean's connectors on the batteries with EC3's to match my other 2200/2700MAH batteries I already have so it's all consistent.

[DMJAX]

So I know I need to level the swash due to all new linkages but do I need to go through the entire AR7200 setup as well? I didn't touch any servo's or the gyro/receiver. I still want to ensure the servo's go to 90 degrees as they should doing the setup procedures with 0 Trim/0 Sub Trim, just not sure how much I need to mess with.

[rcflier1]

it can't hurt. that way you know it's right.a few more min on the bench can save hours of repairs later.

[Ron_R]

Originally Posted by DMJAX

So I know I need to level the swash due to all new linkages but do I need to go through the entire AR7200 setup as well? I didn't touch any servo's or the gyro/receiver. I still want to ensure the servo's go to 90 degrees as they should doing the setup procedures with 0 Trim/0 Sub Trim, just not sure how much I need to mess with.

You do, yes. Measure twice, cut once.

[DMJAX]

Took her out today, first time. Should have waited, windy day, but it's been that way for weeks. Anyway, pointed her into the wind, spooled up (Normal mode) and up she went! Drifted left somewhat, but didn't let her get away, landed safely.

Tries again, better (wasn't near as scared this time), hover fairly well, she moved around but I easily brought her back. Did several more takeoff, hover land routines, that's my comfort level right now and with the wind, didn't want to press the issue.

Only issue I see is the tail wags pretty hard, constant. Doesn't blowout or anything, just a jerky horizontal wag. I set the Gyro Gain down from 77% to 50% in normal, will try again next day when it's good weather.

Any other thoughts?

[ArchmageAU]

Originally Posted by DMJAX

...

Only issue I see is the tail wags pretty hard, constant. Doesn't blowout or anything, just a jerky horizontal wag. I set the Gyro Gain down from 77% to 50% in normal, will try again next day when it's good weather.

Any other thoughts?

Check the mechanicals on the tail before gain adjustments. Things like pushrod friction, tail feathering shaft, tail grip bearings, etc.. Any mechanical binding or imbalance can cause wag as much as gain settings.