[NSRCA-discussion] Bearing tip for OS 1.40 RX

[Ed Alt]

BlankThis is an FYI for anyone with a new OS 1.40 RX.  Thinking about running with the stock bearing for even a short time?  Think again.  I was anxious to get a new model flying for this weekend and decided not to take the time to first swap out the junk stock bearing in a new RX.  I figured if I dosed it with after run oil after every flight I could get through he weekend and then do the mandatory swap to a sealed bearing.  Here's the full history.  

Friday, June 30 I did two break in runs on the ground.  Didn't do any after run between these two runs.  They were only 30 minutes apart. What could happen?.  Another 30 minutes after the 2nd break in run, did a short flight.  Had a transmitter trim lever problem, landed quickly, de-fueled, ran it dry, literally ran nearly 20 squirts of Amsoil Metal Protector through it.  Doused it.  Got it home, added a full carb barrel of castor oil for good measure and worked it through.  Yeah, that ought to do it.  Dehumidifier running all day, all night in the basement...

Saturday, July 1 dawns.  Bearings still feel OK.  Head to the field.  Fly.  Work a carb barrel of castor through it.  Repeat for 3 more flights.  Note that the bearing is starting to feel rough already.  Take it home, swap for a sealed bearing.  Note that the bearing is rusted already and that the crankshaft has light scoring from the inner race turning on it.  7 runs, handled like a newborn baby.

IMO, it is a disgrace that OS continues to produce this engine with a trash bearing that can't stand up to even the most careful use for more than a day.  They KNOW what should be in there, since they do it for the EFI version.  Lesson learned, if I ever do use another new RX, I'll never again make the mistake of doing even a single run without first swapping the main bearing.  It's not like the sealed bearing is all that expensive either.  I get them locally for a little over $11 each and they work great.  You don't even have to waste money on an overpriced Boca or EFI verson from Tower.

Ed

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