Sunday, December 23, 2007
Yellowbird is whole again. After five long months sitting in a corner of the FBO hangar due to a cracked engine crankcase, she's finally fixed, reassembled, and signed off. Yesterday I paid the bill and picked up her keys and maintenance logs from the shop - now I just need to find a day with flyable weather. Until then, I have a box of assorted airplane refuse to dig through. This initially consisted of parts that were replaced when the engine was rebuilt. Added to the list as the process went on were various pieces that were replaced during the annual airworthiness inspection, and a few parts that were removed when I indulged in some convenient upgrades.
The major upgrade was the replacement of the stock exhaust gas temperature gauge with a JPI EDM-700 digital engine monitor. The old gauge picked up the temperature from the exhaust of the #3 cylinder, hopefully giving the pilot a general idea of the combustion efficiency of the fuel air mixture. The EDM-700 tracks exhaust gas and cylinder head temperatures for all four cylinders as well as oil and carburetor temperatures, providing a much more comprehensive picture of the engine's operation condition. The old gauge was in working condition when removed, so I may offer it up on eBay.
Also removed were the mixture control cable (top) and the engine oil pan heater (bottom. The mixture cable was replaced by a vernier type cable which allows more control when making fine adjustments. The oil pan heater was replaced by a complete Reiff preheater system which warms the oil as well as all four cylinders. I may put these up for sale also, but they may be harder to sell. The mixture cable would have a very narrow application - it's a standard Cessna part, but it's length may be suitable only for other Cardinals. The oil heater of uncertain origin (it was on the plane when I bought it, and there's no record in the logs of its installation) so it may not be suitable for reinstallation on a certified aircraft.
When the engine was remounted, the rubber shock mounts were replaced. These enclose the bolts that attach the engine to the engine mount, and consist of a chewy rubber center surrounded by a hard outer sandwich of rubber and metal.
During the annual inspection, the fire extinguisher was found to have low pressure. I took it to be refilled, but the extinguisher folks recommended replacing it, since the valve was plastic and apparently prone to leakage. That turned out to be a good call - not only was it leaky, but it was broken. (The black tube is supposed to be part of the valve mechanism.) So, Yellowbird has a brand new fire extinguisher, and I have an absolutely useless broken one. Maybe I could make a lamp out of it...
The engine had been sent off to Mattituck for repair a cracked crankcase. The repair included a complete disassembly of the engine and inspection of each part before reassembling the engine around a replacement crankcase. Any parts that were defective were replaced. The old crankcase presumably was repaired and put back into circulation. Other lesser parts were boxed up and returned with the repaired engine.
Here we have a crankshaft counterweight (left) and the four piston pins (right). The counterweight attaches to the crankshaft and helps dampen the vibrations of the engine. How it does so is a bit above my ability to visualize, but it apparently involves some of the same physics involved in the motion of pendulums. The piston pins connect the piston-bones to the connecting rod-bones. (Oh hear the word of the Lord!) These are all very impressive bits of metalworking, and quite hefty. They may make nice paperweights.
Piston rings. In the foreground are the eight compression rings. The ones on the right are clean and shiny on both sides. The ones on the left show carbon deposits on one side (barely visible in the photo). In the background are the oil control rings. Again, these are nice looking bits of metal, showing a lot of precision in their design. It would be a shame to throw them away, but I don't know what to make of them. They're a bit too large for napkin rings, but too small for that ring trick that magicians do. Bracelets, maybe?
Candleholders and napkin rings have got me thinking: I now have an outdoor balcony where I can do airplane repairs, so the Bachelor Kitchen has mostly reverted to its original purpose. But that doesn't mean that I have to give up one of the benefits of bachelor pilot living, namely keeping airplane parts around the house. So, here you have it - the Bachelor Pilot Table Setting.