Bearings, Screw, and See-Saws

[Gr4yb3ard]

I guess I did not hit submit before my power went off.

If this is a repeat, my appologies.....

After two days of intense GAUI-200 mayhem, my bird started acting unusually. She would refuse to respond to controls sometimes, then suddenly do something unexpected.

(...and people wonder why we call them she...-)

I found that one of the see-saw arm bearings had failed, and while by itself, was hardly noticable, the linkage seems to amplify the problem to the point where the flybar would not rock without considerable force, which explains the control problems.

I would'nt mention it, but for the fact that it was one of those difficult problems to find, and that we've seen so many bearing and see-saw problems here. If you are trying to track down flaky control issues, add this to the list of things to check. It went from fun and stable to scary and out-of-control in half a pack.

So... I've just stocked up on bearings. Particularly the vital (203250) which is used in the see-saw and many other places on the heli. Also I got two sets of new bearings for the tail rotor shaft, and one each of all the others on order.

Well, tiny, close tolerance, high-speed open bearings running outdoors in a gritty enviroment. Who woulda thunk it!!!

I think the solution is to pack them with lithium grease and teardown/degrease/repack at a specific interval, just like a <real> helicopter. Doubt we'd find a sealed bearing this small, and precisely this size but I'll check.

As far as the screws go, I know an aviation fastener company down here. I'm going to check on the availability of av-grade screws this small, but from experience, I'm not holding my breath, I've already ordered my bag '0 grip screws like everyone else ;-)

Gr4yb3ard
"...Orville: Why do they call it the "Jesus" bolt???..."

[rotorhead58d]

i spray silicon on my 200's head and tail before flying. keeps everything greased up nicely.

[Gr4yb3ard]

Hey, Rotor, good idea, that sounds a lot cleaner!
Won't be quite as perfect for ball bearings as a grease, but I doubt we'll see 500,000 miles on these things anyway ;-)

Gr4yb3ard

[rotorhead58d]

i stole the idea from buzz. i can not tell a lie:o

[Gr4yb3ard]

Rotor,

Having spoken with you previously, and at length,
I would expect no less on either point... ;-)

Gr4yb3ard
"...INCOMING!!..."

[Buzzkill]

LOL. The spray definately helps these little buggers. I spray the crap out of everything non electronic. Gets messy sometimes if you don't keep it clean.

[Gr4yb3ard]

Yeah, but my experience with silicone is that it "goes away" after a few hours and does not attract grit nearly as well as grease. With open bearings this is a plus. It cleans as well, double plus.

Grease + grit = valve grinding compound.

Gr4yb3ard

[Buzzkill]

What silicon are you using? Mine has stayed on for weeks.

[rotorhead58d]

What silicon are you using? Mine has stayed on for weeks.

i'm using my x g/f's bwhahahahahahahaha

[Gr4yb3ard]

LOL!

BEST BRAND GOING!!

No, seriously, good silicone sprays are mostly silicone, with an evaporant. The spray stuff goes away and leaves the silly, which goes away as well after time.

WD-40 is a rather slow example, I *think* it's got some petroleum in it, but it sure goes away better than grease.

Silicon is a high pressure lubricant, but Not a real good lubricant, Graphite is better, but ugly. Neither is as good as grease in a ball bearing. Lithium grease is about as decent a lube as you can find for most applications, and it doe'snt stain too bad until it picks up dirt from the air.

Actually, the best bet going is tri-flon applied regularly, but it's expensive and messy. Molybdenum disulphide or graphite in a heavy grease (high-temp disk brake wheel bearing greases) are the best for severe service where it's got to stay on.

Gr4yb3ard
"...moral: lube thy bearings, yet not thy carpet..."

[goldslinger]

I use food grade silicone spray on gears, belts, etc. and it stays, and stays. . .

I use phillips grease (used in the famous 'greaser' for larger helis) and pack bearings with syringe. I let it kinda squish out from all around; never have to pack it after that as this stuff is even thicker than any other grease I've found. The excess oozes out to equalibrium the pressure inside the bearings after a flight, and after that, what is in there STAYS in there. I leave the little excess grease that oozes out to form a dirt barrier for the bearings.

You will crash and replace the bearings long before You ever have to replace them for wear, even the tail bearing, but on the tail bearing, May have to re-apply on occasion to keep the grease fresh. Oil gets slung out in short order; heavy grease stays and offers negligable amount of resistance over oil.

Gary

[SlowWhite]

I'm haveing a problem with the top Main shaft bearing popping out of it's holder constantly during aerobatics causing the main shaft to sway back and forth, and is probably bending but I usually crash and bend that anyways.

any idea's on how to hold keep that main shaft bearing in the block?

[Buzzkill]

Do you have the plastic or cnc main boom? You could carefuly CA the bearing in the boom. I had a swash on my first Gaui 200 that kept popping out. I CA'ed it and have over 100 flights on it with no problems.

[psindrup]

I'm haveing a problem with the top Main shaft bearing popping out of it's holder constantly during aerobatics causing the main shaft to sway back and forth, and is probably bending but I usually crash and bend that anyways.

any idea's on how to hold keep that main shaft bearing in the block?

I little drop of green Locktite on the outer racer of the bearing will do the trick.
Just be very careful that you do not get it "inside" the bearing.

Peter