REFLECTOR: Interesting Gotcha this morning

[Richard Riley]

Foam polyisocyanurate would do 
it.  http://www.findarticles.com/p/articles/mi_m0UBT/is_39_13/ai_55909848

At 08:47 AM 11/6/04, you wrote:
>That's a good idea.  Do they make a non-flammable version of spray 
>expand-a-foam?  Extra firewall protection.
>Is the spray foam even flammable?  I'd imagine yes.
>
>
>  Brian Michalk  <<http://www.michalk.com/>http://www.michalk.com>
>Life is what you make of it ... never wish you had done something.
>Aviator, experimental aircraft builder, motorcyclist, SCUBA diver
>musician, home-brewer, entrepreneur and barely single
>
>-----Original Message-----
>From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org]On 
>Behalf Of robajohnson at comcast.net
>Sent: Friday, November 05, 2004 7:00 PM
>To: Velocity Aircraft Owners and Builders list
>Subject: Re: REFLECTOR: Interesting Gotcha this morning
>
>I had put a shot of spray foam in each duct on each end. Easy to get out 
>or punch through if you need to run something else through there but quick 
>and eay way to keep the water and cold air out.
>
>Rob
>
>-------------- Original message --------------
>
> > After fixing the leak in my sump tank, I decided I would clean off my
> > engine and reinstall my dip stick tube as it had become loose.
> >
> > I used the spray on engine degreaser and hosed it off afterwards. It took
> > two applications to get it really clean as the loose dip stick tube had
> > been leaking oil. Rinsed it down real good and let it sit for an hour
> > before taxing back to the hanger from the wash rack.
> >
> > Fired her up this morning and taxied out to RW 13. About half the way
> > there I started getting a pop corn sound in my headset! It was pretty
> > loud. I turned the ANR off and on, no change. Tried EI or right mag, no
> > change. Changing the rpm did seem to increase the rate of popping but not
> > as much as the rpm was changing. Turned off the intercom, slightly less
> > volume. Turned off the strobes, no change.. changed comm's the quality of
> > pops changed but still there.
> >
> > All indications voltage and amperage looked within norm.
> >
> > I sadly taxied back to the hanger... Damn, and we were planning a trip to
> > Mesa Verde tomorrow.....
> >
> > At the hanger I cycled electrical power and no change. Cycled again(I'm
> > stubborn) and it stopped!! Hmmm... Now thats good and
> > bad... Intermittents can be real buggers.. I could not get it to come 
> back.
> >
> > I got out , looked at the alternator wiring, as much as I can see with out
> > de-cowling.. Popped the nose door and canard hatch. Nothing obvious???
> >
> > My friend the local A&P/AI wandered by, he said he got worried as he heard
> > me taxi out but not take off. I told him the story and he didn't have much
> > more to suggest, except that it may have been an external source, some
> > local transformer or someth ing. that got my hopes up a bit, but not 
> much...
> >
> > I decided to fire up and see if it would come back by taxing
> > around. pushed out of the hanger, "prop clear!" and started the
> > engine. He got this funny look on his face and gave me the kill signal
> > while pointing back at the engine. I stopped it and bent out and looked
> > back. There was a puddle under the engine. I had not primed or ran the aux
> > fuel pump.
> >
> > I jumped out and went back, stuck my finger in the liquid, smelled,
> > tasted, it was water?? Wow, it was coming out of he gap in the cowling
> > where the vent and fuel whiffle valve lines are.
> >
> > It must be from washing the engine I said. Strange it didn't drain when
> > the cowling was off.. I went to the nose and lifted. Water gushed
> > out!!! Must have been 1/4 gallon or more!
> >
> > Then I realized there are gaps where the oil lines and wires go into the
> > two ducts on either side of the fuselage. In my quest to really rinse down
> > the engine and firewall to insure I got all the degreaser out I had 
> sprayed
> > a bunch of water into the ducts! Who knows how many BNC and other
> > connectors are in there getting soaked. Not to mention the main big ol
> > wires for the starter/alternator. The shape of the fuselage is like a
> > banana and any liquid put in the firewall end of the duct would migrate to
> > the center of the fusalage...
> >
> > In fact I had noticed one time after I had changed the oil and really
> > bothched catching the oil from the filter, its mounted right above the 
> left
> > duct. The oil poured all over that spot. A couple weeks later I had the
> > back seat out and there was an oil stain where there is access to the 
> duct,
> > the pilled oil that got in the duct it had migrated up the duct to the
> > middle of teh fusalage.
> >
> > I held the nose up for about 5 minutes until all dripp ing stopped.
> >
> > Fired up and flew around for half an hour with no popping noise. Now I
> > don't know for sure if it was the water that caused the popping noise, but
> > I do know I don't want to get that water in there again! It could also
> > freeze and do who knows what?
> >
> > Scott
> >
> > "Those who sacrifice freedom to get security, deserve neither."
> > - Benjamin Franklin
> >
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