General Check list after a crash

Lee

Well-Known Member
I just ditch my 600 today, and once i got it home, I decided to strip it down to see what was broken.
Thought i would share some of the things a look for when taking apart a broken helicopter.

Have two boxes. 1 for good parts and 1 for broken parts.

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A trick for finding out if you have a bent feather shaft is to, take the two blade grip ball links ( or control arms in my case) Hold them together, then rotate the feather shaft with an allen key in one end. If the shaft is bent, you will see movement in the ball links or arms.
This can be done with the tail as well to check the centre hub.

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Take the main shaft out and on a clean glass surface ( i used the cooker) roll the shaft across it. If it wobble across then its bent.

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Check each bearing for grittiness. A sign of damage. Mine where fine except one that got mud in it. I managed to clean it out with some silicone spray.
Turn all the servos by hand to there limits. If you feel crunching, you have broken gears inside.
Check linkages for damage. Bent arms or broken ball links.
Check all wires for damage.
If its a belt drive, check the belt for fraying or damaged teeth.
Check main and auto gears for damaged teeth and (torque tube tail gears) if you have torque tube drive.
Check blades for damage. Some may be obvious, but some may be stress fractures you cannot see. Give them a slight bend to see or feel if theres a problem.
There are many other things to check like electronics. They can be done on the rebuild.
Feel free to add anything else you think of. Or top tips.


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coolgabsi

Super Mod & DEAL KING!
That blade grip trick is really good for bigger birds ESP as their feathering shafts are tight on the dampeners and the bend is sometimes really really subtle.

I found out that technique to be really useful and someone at te field told me about it... Nice documentation there...

Fly safe!! :) have fun!
 

zenmetsu

Member
Great writeup. I admit that I often don't check feathering shaft after minor incidents with my 250, will probably be a different story on the 500.

I found that I've blown a few one-way bearings in crashes. It may be a good idea to check the bearings in the gear as well.

I have run into a problem where the main blades seem to rotate freely after cutting throttle, but then they bind after coming to a stop and I have to turn the main blades clockwise until the bearing pops and the blades are free again. The bearings will usually fail shortly after this point.

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Might wanna check the LiPo packs for damage also. :)
 

Lee

Well-Known Member
Never mind the OWB. Check this out. :eek1:
OWB Shaft destroyed.

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Once there have been a few posts with other valuable additions to the check list, i will edit the first post to include them all, and maybe Tony could Sticky it to the top of the beginner thread.

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Lee

Well-Known Member
When the head i spinning at 2300RPM with 600mm blades on it, and they stop abruptly in the mud, things break LOL The one way bearing would you believe is actually ok. Only the shaft broke.
So breakage list is:
Main Blades
Bottom plate
Front torque gears
Main gear
1 landing skid
OWB shaft
And my canopy is a bit scratched :(
I cracked the plastic case around my new Castle ESC where the screws hold it together (only cosmetic). I have no idea how, as its in the middle of the frame and it didn't move??
 

zenmetsu

Member
Yup. Impact forces can do strange things.

I have seen flexible shafts, much like the tail boom supports, flex and jump out of place to the point where trying to flex them to put back into place results in failure.

Add to your list: do a check of all screws to make certain that they didn't pop the loctite and work loose. I have had screws in my frame jump out, never to be seen again. :)
 

coolgabsi

Super Mod & DEAL KING!
On my vibe... I bowed the frame halves once just by a small crash... It's a g10 frame... I had to do a full repair and rebuild but it was crazy how my frame would take that hit inside the canopy whe canopy didn't have a scratch!! Lol

Fly safe!! :) have fun!
 

Tony

Staff member
Lee, you and Gaba both have the option to sticky a thread. Just make sure it's worthy. I think this one is IMO.

and wow, I have never seen a sleeve like that shatter as it did. That is some force right there lol.
 
Hey Lee,

Okay...I'll ask and show my "newbie-ness"...What is an "OWB"? I just found out what a "FET" is, recently from Tony!

It would be really awesome if you mucho experienced heli-guys posted a list of heli "Acronyms" for us newbies? Or at least "defined" them in your posts?
I know...I'm not a skilled/fast "typist" either. And it makes typing so much easier when I can abbreviate stuff. Just a suggestion...

Thanks for reading my post!
 
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