----- Original Message -----
From: "Europa Aircraft" <europa@gate.net>
Subject: Re: Things that go bump....
>
> > Hi Guys,
> > As I was the one flying the factory 912S powered trigear when this
> > happened, I can assure you after investigation it was indeed carburetor
or
> > induction system icing. After removing the cowling immediately upon
> landing,
> > I first noticed that the starboard carburetor was noticeably cooler than
> the
> > port one. Also, inside the intake manifold was a considerable amount of
> > water! Not merely damp, but dripping wet! Maybe in other cases it is
> another
> > cause, but this was CLEARLY carb icing.
> >
> > Jim Thursby
> >
> >
> > ----- Original Message -----
> > From: "Fergus Kyle" <fkyle@bigwave.ca>
> > Subject: Things that go bump....
> >
> >
> > > Funny thing -
> > > Cheers. I fly a North American Yale (Harvard's 'uncle' with a Wright
> > > Whirlwind 425hp) from The Can. Warplane Museum locally and have done
> > > since we finished it in 1992.
> > > First time out of the circuit last June, we were enroute to an airshow
> > > about one hour away, and were 25 minutes into the flight when I got a
> > > thump in one or both rudder pedals. It was an instantaneous 'rap', as
if
> > > someone had whacked the back of the pedal with a small hammer.
> > > I said to my buddy, "you feel that?". He hadn't - he's in the back
seat
> > > sorting out maps, so I had him put feet to pedals.
> > > After ten minutes he was beginning to question my contact with
reality,
> > > when it happened again. Five minutes later we took TWO whacks with the
> > > engine smooth as a kitten. I turned back and he began to point out
large
> > > roads and suitable fields.
> > > During our return this began to occur more often and in greater
spurts,
> > > so that by the time we got back to base, the tower were ready to call
> > > out the rescue crew.
> > > Ground runups brought nothing, so the complaint raised eyebrows but
> > > little reaction, except that it seemed to affect only the port magneto
> > > and applicable plugs. We rewired the plugs (rear for port mag) and
runup
> > > was fine. Second long trip was fine till about 25 minutes and guess
> > > what? Definitely port mag so we took the mag part and found dirt and
> > > loose material. Cleaned it up and runup was OK.
> > > This time I stayed in the circuit at high power, and sure enough after
> > > 20 min. or so we got thumped again. On return, the boss stripped the
> > > inbuilt condenser and we tested it under heat. There it wasw. When the
> > > engine had transferred enough heat to the mag, the condenser began to
> > > break down, and one miss was enough to thump the pedals under foot.
> > > Replaced the condenser, reinstalled and she purrs again just like she
> > > always had. So mebbe it ain't all gasline contamination. Just like ol'
> > > Barney used to say, "3 things, it's gas, spark or timing".
> > > Here endeth the lesson.
> > > Happy landings
> > > Ferg #A064
> > >
> > >
> > >
> >
>
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