Ball bearing problems

I like flying with small acro trainers.
I used a OS 50 SX for several months on a Soprano (1,55m - 2,6 kg - APC 12 x
6 - Cool Power 15 % Nitro) with great satisfaction. Suddenly the engine
lost some power. Reason : several balls in the rear ball bearing where
damaged, and the particles did ruin the engine. OS (Graupner Germany)
accepted no warranty.
I replaced the OS by a Magnum XLS 46. Performed well after runnung in. A few
weeks later : sudden power loss and same story as above. Chrome did come
apart of the balls of the rear ball bearing.
As far as I heard, this happens very seldom.
Can there be a common reason ?
Thanks for anny comment.
Reply to
Jos Truyen
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15% nitro runs hot. Were you running your engines too lean? The chrome plating either got too hot, or you got hold of defective engines.
Reply to
Vance Howard
you should only be running 15% in high performance or cold weathe
applications. with a trainer type of aircraft you only need 5% and tun it a little rich on the ground as it will lean out once you ar airborn
-- papama ----------------------------------------------------------------------- papamac's Profile:
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Reply to
papamac
The last I heard, Cool Power used about 16% all-synthetic oil. Your 2-stroke engines are probably better off using fuel containing at least 18% oil with at least a small amount being castor oil. The castor oil adds a margin of safety in case of a lean, too hot run.
Jim - AMA 501383
Reply to
James D Jones
MAYBE NOT ENOUGH LUBE IN THE COOL-POWER FUEL ( or maybe no lube )
Run the engine slobbering rich and check for oil-residue from muffler You'll see the proble
-- hall wo ----------------------------------------------------------------------- hall woo's Profile:
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Reply to
hall woo
This seems to be more and more common with engines running Cool Power. I just sold 4 sets of ceramic bearings to some heli fliers using the OS 50 SX-H engines who had exactly the same problem. My advice would be to make sure you use a rear bearing with a high speed plastic retainer and run a fuel other than Cool Power.
-- Paul McIntosh
Reply to
Paul McIntosh
the 50 sx is a ringed engine....unlike the abc engines that must be run in 2 cycle to come up to temp for proper piston cylinder fit a ringed engine should be broke in 4 cycle at first then after a few tanks to 4 cycle breaking into 2 cycle (plenty rich) I suspect a lack of lube and a 12 x 6 prop seams to be on the large side (too high of load...too much heat) for this engine it might be ok after breaking in on a smaller prop, by running a smaller prop for break in it will run at a higher rpm and what comes with that is a lighter load with more fuel that come with more oil which carries away the heat as well as more lubrication I have read the Os manual and see that they recommend a 12 x 6 but personal experience with my 50 sx has shown that a 11 x 6 is a much better choice for this engine... mine is 3 years old and I have run 11 gallons of power master 15 % thru it and it still has original bearings and is still as strong and smooth as ever....I ran the first 3 tanks in full 4 cycle then the next 5 in a 2 - 4 break and since then in a semi rich 2 cycle all with apc 11x6
Reply to
Andrew Noll
This is speculation on my part, but it appears that you are in Belguim, so do you perchance have engines designed for use with 0% nitro, which will have higher compression than an engine designed for nitro? 15% nitro in a high compression engine swinging a large prop, and using inadequate oil in the mix is bound to spell disaster.
Paul McIntosh, you surely know whether OS and Magnum suppliy European engines with higher compression than US engines. Let us know!
Geoff Sanders
Reply to
Geoff Sanders
Therein lies the difference. You used Powermaster which has a very good lube package.
-- Paul McIntosh
Reply to
Paul McIntosh
They are all the same. Many of the Brits complain about the performance on low/no nitro fuels with the Japanese and Chinese engines. Many of them are now seeing that the engines are designed for the mass market (US).
-- Paul McIntosh
Reply to
Paul McIntosh
Just another thought. If the chrome came off the balls, they you have a real big problem! The balls are solid chrome-steel, not plated!
-- Paul McIntosh
Reply to
Paul McIntosh

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