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From: "Perry Mick" <pjmick@mail.viclink.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] Re: Post Mortem on Steve Brooks RD-1B
Date: Tue, 16 Nov 2004 09:40:11 -0800
Message-Id: <20041116172849.M93029@mail.viclink.com>
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This is good news, I was worried there for a bit. Glad it isn't a design 
issue, I recently bought Rusty's RD1B. Look forward to hearing what the 
source of the clog was.

If there was a restriction in the oil line going to the drive, such that the 
drive "saw" a low oil pressure, could that cause something like this? Just a 
thought...

On Tue, 16 Nov 2004 11:10:33 -0500, Tracy Crook wrote
> Total time on drive was 20 hours.   Steve noticed the problem as an 
> oil leak from the input shaft oil seal.  Internal inspection showed 
> the input shaft thrust bearing roller cage which is a polymer cage 
> to be partially melted and most of the rollers were out of the cage. 
>  Overheat was the obvious cause of cage failure.  Rear race of 
> bearing was seized on input shaft and was 'blued' from heat. This 
> allowed the shaft to move back and contact the adapter plate.  All 
> sorts of nastiness resulted from this but the details are not as 
> important as the root cause.  Amazingly, the drive continued to 
> operate normally but the time between roller cage failure and 
> discovery of the problem is unknown. 
> 
> The oil passage from the input shaft pilot bearing to the thrust 
> bearing was found to be clogged and no oil was getting to the thrust 
> bearing (except for incidental splash).  What caused the clog has 
> not been determined.  I will attempt to carefully grind away the 
> input gear and see what it was as time permits. 
> 
>   
> The rear race was spinning against the adapter plate and acting as 
> the thrust bearing while being lubricated only with splash.  That 
> Mobile 1 is amazing stuff!
> 
> A careful inspection of the gears showed no evidence of damage or wear.
> 
> Corrective action:  Replaced the input shaft assembly and thrust 
> bearing, installed nylon snubber/spacer to bring input shaft endplay 
> into spec.
> 
> Tracy Crook,   RWS

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