CO mystery - any ideas?

Andrew Gideon wrote in message gonline.com...
I thought I'd let you all know what's going on.

First, a mechanic with whom we checked claimed to be familiar with the
Cardinal's scoops, and said that the R182 had no such thing. Given that
the tail structure of the Cardinal is so different from other Cessnas,
apparently, this isn't too surprising. But I have to admin: I'm still not
completely certain.

However, we've had the extensions installed (although I've yet to see them;
the airplane pulled out as I arrived at the airport yesterday). The
airplane has flown 6.9 tachometer hours since then, and has been showing a
steady zero reading on the CO detector.

So...it looks good at the moment.

- Andrew

Sounds great! It's always nice to finally solve a problem. How much
did you extend the pipes? I am also interested in how the FAA will
view this. OK or not, as it is a mod to major component. 337 maybe?
Congrats!

Regards,
Bruce

Andrew Gideon wrote in message gonline.com...
Our Cessna R182 is getting CO in the cockpit. We've now had three different
shops look at it multiple times, all to no (complete) effect. They've done
things like resealing the firewall, the gear-wells, the exhaust, and the
like. But still we get CO.

We've swapped CO detectors around between planes, so the detectors' results
are trusted.

One interesting oddity: turning cabin heat on does seem to get rid of the
CO.

That's common. Its a well talked about myth that turning off the
heater gets rid of CO. The CO comes around the slip stream and slips
into the cockpit. Also, there really is no way to "turn off" the heat
the doors just aren't that good. I carry a digital CO detector in my
plane. After my last exhaust leak I got 1500ppm with the heat on and
800ppm with the heat off. Still more than enough to make you sad. What
works well is to open lots of windows and blow a lot of air around.
Diluting the air with fresher air keeps the ppm down.

-Robert

Robert M. Gary wrote:
: 800ppm with the heat off. Still more than enough to make you sad. What
: works well is to open lots of windows and blow a lot of air around.
: Diluting the air with fresher air keeps the ppm down.

Sucks for a Cherokee driver that has only one 6x4" window. Lean 'er 'till she
wheezes to keep the CO (and fuel burn, engine deposits, detonation potential, etc)
down I guess. There's no acute effects of NOx are there?

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

On Tue, 16 Nov 2004 13:07:57 +0000 (UTC),
wrote:

Robert M. Gary wrote:
: 800ppm with the heat off. Still more than enough to make you sad. What
: works well is to open lots of windows and blow a lot of air around.
: Diluting the air with fresher air keeps the ppm down.

Sucks for a Cherokee driver that has only one 6x4" window. Lean 'er 'till she
wheezes to keep the CO (and fuel burn, engine deposits, detonation potential, etc)
down I guess. There's no acute effects of NOx are there?

-Cory
NO is more deadly than CO. The 8hr exposre limit in ontario is 3ppm
vs. 35ppm for CO

Since noticing this discussion I started looking more closely at the
location of the exhaust stacks on my Archer. They are forward and towards
the pilot's side of the engine air intake. That makes sense since it allows
the prop wash to swirl the exhaust gasses away from it. More interestingly
the exhaust might swirl up past the pilot's vent window, possibly allowing
CO etc to enter the cockpit if that window is not sealed well. This makes
me wonder if some exhaust gasses might enter the Archer's cockpit during
taxi, especially if a scoop is installed in the vent widow.


--
Regards,
Mike

http://mywebpage.netscape.com/amountainaero/fspic1.html
wrote in message
...
Robert M. Gary wrote:
: 800ppm with the heat off. Still more than enough to make you sad. What
: works well is to open lots of windows and blow a lot of air around.
: Diluting the air with fresher air keeps the ppm down.

Sucks for a Cherokee driver that has only one 6x4" window. Lean 'er 'till
she
wheezes to keep the CO (and fuel burn, engine deposits, detonation
potential, etc)
down I guess. There's no acute effects of NOx are there?

-Cory

--

************************************************** ***********************
* Cory Papenfuss *
* Electrical Engineering candidate Ph.D. graduate student *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************