----- Original Message -----
From: "John Slade" <sladerj@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, March 03, 2004 7:12 AM
Subject: [FlyRotary] Re: 13B smooth running issues


> > I purchased a 5/8 heater nipple from
> > CarQuest that had a 1/2"NPT fitting...
> We must be talking about different holes. This one's almost 1/8 NPT, but
the
> same theory should apply.
>
> By the way - I discovered an "interesting" failure mode yesterday....
>
> I took her out for her first taxi test. First impression was that the
engine
> was running MUCH smoother with the prop in place. Still rich, but much
more
> responsive. There was a metallic noise I hadn't heard before, so I swung
her
> around and taxied straight back. As I shut her down I noticed a prop
> vibration that didnt seem right.
>
> There was a LOT of lag on the prop. Buly peered down into the flywheel
area
> and spotted a bolt lying at the bottom of the case, just waiting for the
> best opportunity to jump up and attack the expensive and really important
> piece of wood right behind the redrive. :(
>
> Wiggling the prop a bit more I noticed that the flywheel was moving a
little
> with respect to  the counterweights behind it. I removed the redrive. The
> entire damper plate / flywheel assembly was loose. I removed the damper
> plate and found, behind it, the 6 small bolts and one very large central
> bolt that hold the flywheel in place were all loose. I said 6. Actually
> there were 5. The other one, the one Buly found, had already come out.
This
> situation could have taken a very serious bite out of my ass if the
> remaining bolts had come out during the first flight. Can you say
> "catastrophic failure"?
>
> I know what happened. Three years ago, when we were making the engine
mount,
> we had assembled  the redrive to the engine. We'd mounted the flywheel and
> damper plate, probably finger tight,  at that time. For three years the
> engine had sat around with that damper plate in place hiding the loose
> bolts. When it finally came time to install the redrive properly I had
> forgotten that the flywheel had never been torqued down. It had been "part
> of the engine" for all that time, and I'd ASSumed that it had been
correctly
> installed when the engine was built. I guess this is why we do taxi
testing.
>
> Today I'll pick up a new bolt from NAPA and a new bottle of locktite.
>
> Don't feel bad, John.  With our projects spread out over years instead of
weeks, it is very easy to see how that could happen.   Paul Conner

> >>  Homepage:  http://www.flyrotary.com/
> >>  Archive:   http://lancaironline.net/lists/flyrotary/List.html
>