----- Original Message -----
From: "John Slade" <sladerj@bellsouth.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, March 03, 2004 8:12 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.
>
>

Very glad to hear you caught it in time, John.  You experience points out
what I believe is absolutely essential - anytime something doesn't seem
right, immediately (or as soon as you safely can) stop and find out what it
is and correct it.  Don't fly (or even run) with unexplained anomalies, true
some may be benign but the others can kill you.

Reminds me when I had the DAR come out and give me my inspection.  I had
gone over the aircraft several times with a fine tooth comb (I thought at
least) only to have the DAR find that every bolt on the control surfaces
interconnect with the controls were not torqued.  Had put them on finger
tight as I had awaited some special washers that one of Van's service
bulletin called for placing over control rods to keep the rod connected
should the rod bearing fail.  I would like to think I would have discovered
this before the first flight - but, you never know.  Whew!

Won't be long now until that first flight.

Ed Anderson