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Engines Plugs Mufflers Fuel > heehee hee YOU better do something OS !!!
 
 
tchavei
rrProfessor
Location: Portugal

Quote 
to say that some people dont have bearings that need replacing after a while is bullsh!t.

Depends on what you consider "a while". I replace mine every 300 flights as precaution and I never had a "hammered" one to date. Running them all at 17000-17500 but they occasionally hit the 20k mark during unload phase and I'm not just hovering around

Tony

PS - here is one of my OS50 Hypers with 287 flights on it:








--------------------
"Perfection and patience usually walk side by side..."
05-20-2008 12:49 AM
HOMEPAGE  
 
 
DS 8717
rrProfessor
Location: Here wishing i was somewhere else

Quote 
I don't get it, I don't get it,,

are you saying every Hyper 50 has a bearing problem rather it happens at 3 gallons or 20 gallons ???

I mean if someone has 12 gallons on their enegine and have no problems, then they have no problems,,, right..

Let me put it this way,the minute you start your engine for the first time the bearings are on their way out.Some just take longer than others.
05-20-2008 02:10 AM
 
 
the Wasp
rrProfessor
Location: Vt

well I rather have my bearing last 20 gallons than 2.6 gallons !!

Topher,, I can do that, but you living in Michigan could probably get a better deal than me, you may even find them on the shelf..

Jim
Buzz Buzz Buzz
05-20-2008 03:16 AM
 
 
the Wasp
rrProfessor
Location: Vt

weller,, I got my $40 SFK bearing ordered,, it is a high speed bearing rated up to 30,000 RPMs, AND it has a "metal" retainer,, yeeup,, it's a rated 1 bearing but from the photo I saw it has 2 more balls than my stock OS bearing,,
I have to pay shipping and tax, but I'm willing to pay the $50 one time at least to see what happens..


the guy from SKF told the salesmen (and don't bite my head off for this) the Phenolic retainer actually could "could" (could) be our problem, because cheap bearings have cheap Phenolic retainers and once they get hot they can flex and vibrate,, OK, that is what HE said !!!

he also said with the amount of bearings the engine manufacture must buy if they are Chinese bearing they are probably paying less than $1 for each bearing,,, I can understand this knowing that Boca must pay somewhere around $4 for a $10 two bearing kit,, brake that down for each bearing ($2 each)..

Jim
Buzz Buzz Buzz
05-21-2008 01:00 AM
 
 
DS 8717
rrProfessor
Location: Here wishing i was somewhere else

Cheap bearings have plastic retainers not phenolic ie: the OS bearing is plastic.
05-21-2008 01:48 AM
 
 
PilotDaz
Veteran
Location: Seattle, WA

Quote 
weller,, I got my $40 SFK baring ordered,, it is a high speed bearing rated up to 30,000 RPMs, AND it has a "metal" retainer,

I've been very loosely watching this thread, but now you have my undivided attention! Today while flying my 600N + Hyper, I started to hear that dreaded "waterfall" sound AGAIN!!

This is the 5th time I've had premature bearing failure in the past year or so. And before anyone tells me I've been running it too hard, my needle is set extremely rich and running well below the rated RPM's. I'm so sick of this problem it's not funny anymore!

I've bought 3 engines, and had 2 warranty replacements when the bearings exploded. When will the madness end?

This time, it's after 17 flights on a BRAND NEW and properly broken in engine. 17!! Last time it was after about 85 flights, which I had a little more patience for.

So wasp, you've found a bearing you think will hold up longer? I have 2 sets of replacement bearings left (From RC Bearings) that I'll use while I watch how you make out with this. Please keep us all informed. If they work out, I'd like to get a set too.

~Team Collective Mayhem - "My anger management class really PISSES ME OFF!"
05-21-2008 02:09 AM
 
 
DS 8717
rrProfessor
Location: Here wishing i was somewhere else

retainer types;
Boca bearings:

+Retainer Material All
Stainless Steel , Chrome Steel , Bronze, Polymite Plastic , Phenolic,
Brass, Full Complement, Teflon, Phenolic w/ Metal,
05-21-2008 02:14 AM
 
 
the Wasp
rrProfessor
Location: Vt

Geee guess what I found

I got thinking I still have my first OS 50 somewhere (silver head), so I found it out in the garage in a bucket with some junk, the crank and piston & liner was out of it but the bearing was still in it so punched out the bearing,,

and guess what this bearing says on it,, (Japan NSK)

now keep in mind this engine was built and sold before Futaba had bought OS,,

the NSK is on the right, not only does the NSK look like a higher quality bearing it is heavier than the Hyper's bearing I removed a couple weeks ago (left)..



Jim
Buzz Buzz Buzz
05-22-2008 06:09 AM
 
 
Unbalanced
Veteran
Location: Melbourne, Australia

I toast bearings through corrosion rather than wear. Same result when you look at the races. I have a big glass bottle full of them from various engines over the years. Purely a result of running exhaust pressure with the cr!p being fed into the engine particularily near the end of the tank.

I took to running 1/3 of a header tank of straight meth/castor mix at the end of the day and the engine is very nearly corrosion free and the bearing life is 1000 times better.

For those that are having real problems with bearings, and can see corrosion on the bearing, it would be interesting to try at least a 1/2 header of clean normal fuel - remove the line from the header to the tank (so the cr!p doesn't get back into the header) at the end of the day.

I have trouble believing the pics of that 100 flight + engine, even the dye in the oil leaves a big stain after a few flights ??

Jeff
05-22-2008 06:51 AM
 
 
tadawson
Elite Veteran
Location: Lewisville, TX

From what I have read, tchavei mixes his own fuel, so what dye?

- Tim

The more I touch electrics, the more I grow to hate them . . . .
05-22-2008 07:04 AM
 
 
lightningrc
Elite Veteran
Location: UK



Wasp glad you took the photo , yours were the same as mine , you can see the difference in the size of the inner race also.

My Second hand NSK is still sounding sweet.
05-22-2008 01:33 PM
HOMEPAGE  
 
 
GMPheli
Veteran
Location: W. Bridgewater, MA USA

The size of the inner race is the same. The bearing on the left has the sides of the inner race turned down so this bearing can also be fitted with a seal or shield.
05-22-2008 02:51 PM
 
 
DS 8717
rrProfessor
Location: Here wishing i was somewhere else

The bearing on the right might have more balls,which means the balls are smaller requiring a thicker race.And the older bearing in the 50 SX was just as bad as the Hyper.

http://www.runryder.com/helicopter/t59399p1/
05-22-2008 02:57 PM
 
 
GMPheli
Veteran
Location: W. Bridgewater, MA USA

Um, OK. But they both have ten balls. And if you look beyond the step you can see that the inner races are the same size.
05-22-2008 04:06 PM
 
 
AAKEE
Senior Heliman
Location: Boden, Sweden

My OS50 Hyper has about 140-150flights (10months since new), there was a new sound from the heli today, probably its the rear bearing thatī starts to go. (Ive heard this sound B4 so Iīm quite positiv that itīs the bearing...)
05-22-2008 09:56 PM
 
 
the Wasp
rrProfessor
Location: Vt

GMP has it right,, I just check and they both fit the crank very much the same,,

it's just an optical illusion cause the camrea was on a slight angle..

Jim
Buzz Buzz Buzz
05-22-2008 10:15 PM
 
 
the Wasp
rrProfessor
Location: Vt

oh,, and,, I called a few places today looking for better prices, and one guy from Timken told me that the Chinese were not finishing the Bearing Groovs, this finishing is some sort of "Wash" that smooth's the Surface of the Grooves,, not good !!

so far, the best price for a Quality Bearing I have found is $34 for a NSK bearing (part # 6902) from a Dealer in Manchester NH (phone #1-603-641-5649)

Jim
Buzz Buzz Buzz
05-22-2008 10:29 PM
 
 
Dilbeck
Key Veteran
Location: Springdale Arkansas

So after all this what is the finally word? Does any one have the definitive answer?

If it doesn't fly sell it!
05-23-2008 01:04 AM
 
 
Blade_Master1
Key Veteran
Location: Canada

IMO poor quality bearings and using 30% nitro with a high compression.

but I could be wrong

JM2C's :)
05-23-2008 01:47 AM
 
 
the Wasp
rrProfessor
Location: Vt

looky looky see what I find !!

a quality OS 50 rear bearing that is marked Japan NSK,,,, now only IF it's the bearing you will receive if ordered ??

http://www.ronlund.com/Merchant2/me...t_Code=OSMG3043

I guess I will make a call tomorrow !!

Jim
Buzz Buzz Buzz
05-23-2008 03:09 AM
 
 
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Engines Plugs Mufflers Fuel > heehee hee YOU better do something OS !!!
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