Repeditive muffler inspection

[N2709P]

There is also the argument over ceramic coating the exhaust system components. Some say that it is just a cosmetic coating and no approval required and others say that it requires an approval as a modification. The only argument for an approval, in my opinion, would be the possible loss of energy for the carb heat. Different color coatings are better than others in containing the exhaust heat within the pipe and not letting it radiate out. The exhaust erosion issue with the ceramic coating is almost nil. We have used it for years on brake calipers and engine exhaust in the racing industry. Have also seen a great improvement in the lowering of heat in the engine compartment of the L-19. These aircraft have always had an issue with high oil temps. I have used it on exhaust pipes on engines that do not use that stack for carb heat with good results. Any other feedback?
N2709P

[Steve Pierce]

Does it coat the inside as well I guess?

[Armstrong]

Usually the whole piece goes in the media and so the internals are coated too. The only snag I see is the medium (pellets) might get trapped in the baffle gills. The racing and muscle car guys use this alot. Very thin layer, I don't think it even flakes it’s that thin. Very robust too.

Would be interesting to try a used muffler first.

[Armstrong]

Oh, and to N2709p’s point, different colors and coatings have different heat emissivity and absorption characteristics, so I would think a professional coating service would have some insights into what would be a most “neutral” coating in that respect. Black or dark would be high emissivity and high absorption, and white, silver, and light colors would have low emissivity and absorption. It does make a pretty big difference. Some even coat piston tops to reduce heat absorption into the crankcase.

[Subsonic]

Annual inspection completed on my PA22. Muffler checked out fine. Put it all back together with new gaskets and flange nuts and used anti-seize on the slip joints going into the muffler. Ordered new Univair carb heat thing that goes on the right side header. OMG do they think highly of those parts! Called Attlee Dodge and talked to somebody there for a while about the PA12 hot rod muffler. He said that because the PA12 and PA22 mufflers have the same part number, several PA 22 owners have gotten FAA approvals to install the hotrod muff on their PA22s. I’m going to have to look into that further.

[walt.buskey]

You're talking about the carb heat "elbow heat muff"? Over & above the many very high-priced parts I've had to purchase over the years, that's the ONE thing I also thought was ridiculously expensive, for 8 ounces of stamped aluminum. OK, yeah, it has that welded stub and the header stand-off spring thing, but really?? Mine was $535. Still the same price? Only bright side is now it's in one piece and I shouldn't ever have to buy another one!

Glad your annual is all done! 57A now sits again, waiting for determination of a lot of stuff --mostly avionics-- that apparently needs replacement. Back to the drawing board....

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[N2709P]

As expensive as these parts seem to be, we need to be thankful that our airframes are not an Orphan. Been there, done that. Not only is the value if the aircraft greatly depressed, scrounging for serviceable used parts in not high on my fun to do list. Look at the prices they want for the junk on the internet. It really comes down to while Tri-Pacers are considered “affordable” to purchase, they cost as much to maintain properly as a Cessna or Grumman. Many times it is more. With airplanes, for the number of hours flown by the average pilot, it is far cheaper to rent. And that is with the rental price of a 172 around $200 an hour. For just the average monthly hangar rental cost you can fly about two hours. That is 24 flying hours a year. Give them back the keys to the plane and walk away.
I had an air mix valve for an aircraft overhauled and one 8/32 screw had a price tag of $800. I went clear to the top of customer service at Honeywell and they confirmed the price. Don’t want to pay it? Ground the jet. The exchange price of a repaired Collins High Frequency radio transmitter was $28,900. Not for the faint of heart. In comparison, the prices for PMA’d parts for our birds are not that bad. I personally am thrilled that we can still get them.
N2709P

[walt.buskey]

A very good point, and I do appreciate the fact that parts for our airplanes are actually still available. I did not mean to discount that fact. One of my former students, now a DER/DAR with his own engineering company, told me "Just bite the bullet and replace it!" after he saw my old elbow heat muff. I did, and am not sorry I did, but the price still gags me... But that's the price we pay, right?

[Jim]

EZ folks, there are others in the room.

[Steve Pierce]

I get frustrated with parts cost especially when I figure out what it cost me to make a part. Some vendors seem to charge a premium price until someone else figures out that they can build that same part, get it approved and sell it at a lesser price and still make a profit. We are fortunate that we fly an airplane that was successful, popular and still supported which is a testament to Piper, there design, design and production philosophy and I am gonna say a touch of luck.