Not Model Aviation but a REALLY scary surprise!

[Robert Zambelli]

The exhaust system on my Cessna 120 requires inspection every 25 hours, according to a placard on the dashboard.
I inspect it every 15 hours.
This last time, I did the inspection after 13 hours and got quite a shock!   
The port side muffler was blown out as seen in the picture. When I inspected it 13 hours ago, there was not a single hole or crack. If fact, I tap it with a screwdriver handle to check for soft spots.
This is the side that is attached to cabin heat, which fortunately I have not used recently.

Bob Z.

[Russell Shaffer]

Fortunate catch.  Time to buy one of those muffler patch kits from Walmart?

[Motorman]

Don't you have a monoxide detector in the cockpit?

MM

[Mike Scholtes]

Wow, that IS scary. Is there a modern stainless replacement maybe? I had a similar but not nearly as bad situation with the muffler on the A65 in my T-Craft, requiring frequent inspection and some repairs. This seems like something there should be (or maybe is) an AD on, in addition to placarded warnings.

[Glenn (Gravitywell) Reach]

Shows you just how hot those babies run!  Good catch.

[peabody]

Hey Z-man....
A friend from NJ was prototyping a stainless 4 into 1 on his Cessna....allegedly a power increase and a weight reduction....it sounded pretty cool, too. Any progress in that area?

[Robert Zambelli]

Don't you have a monoxide detector in the cockpit?

MM

Yes, I have carbon monoxide detectors in both of my aircraft.
Since the cabin heat has not been on in a long time and the fresh air vents were open, I never got an indication.
When the cabin heat in the Cessna is closed, it seals very tight and nothing comes in the cabin.

Bob Z.

[Air Ministry .]

thats the heat box tho / , not a muffler . Is It . So youd loose the warm air in - out through the ole . 

[Robert Zambelli]

Hi, Matt.
No, that is the muffler. I removed the heat boxes to do the inspection.
That's when I found the deteriorated mufflers - inside the heat boxes.

Bob Z.

[Skip Chernoff]

Count your blessing,that could have been ugly. Great catch........PhillySkip

[Robert Zambelli]

Just finished installing the new system.
Upgraded by STC, fits perfectly.

Bob Z.

[Chuck_Smith]

Looks nice! And what's baby blue in the background? Is that Daphne blue?

[Robert Zambelli]

Looks nice! And what's baby blue in the background? Is that Daphne blue?

That's my baby blue 1974 FIAT Spider - one of the most reliable and fun to drive cars I've ever owned! I've had it since 1976.

  Bob Z.

[Mike Lauerman]

'Z' man is very 'car-anointed'.

Glad you found that 'heat annoyance' in time, Robert! 

[RknRusty]

Me too, Bob, I'm sure glad you do such timely inspections. Was it the original muffler, or is that a part that needs periodic replacement?

Damn glad you're still with us.
Rusty

[Chris McMillin]

Those new mufflers look more better, Bob!
Chris...

[Robert Zambelli]

Me too, Bob, I'm sure glad you do such timely inspections. Was it the original muffler, or is that a part that needs periodic replacement?

Damn glad you're still with us.
Rusty

Hi, Rusty - yes, as far as I know, the mufflers were original, from 1946. I could not find anything in the log books alluding to replacement.
The one in the photo was on the port side of the plane.
When I removed/inspected the one on the starboard side, I found several places where it had been welded - more than likely to repair cracks.

Anyhow, the new mufflers will outlast me!

Bob Z.