Jim, Excellent questions. They need to be addressed.
I'm not a mechanic and mustn't play one on the internet. These are the observations of a pilot who has been paying attention for 30+ years. Anything I get wrong should be corrected by those more expert than I. First, let's look at the 58 "engine related" accidents you mentioned in the last decade. We've long noted that most engine failures have nothing to do with the engine, but instead relate to fuel supply issues. So, how many of those 58 "engine related" accidents were caused by a fault in the engine? I'm guessing the number is quite small. Second, time is as important as hours of use. The most common engine lifetime statistic quoted is TBO (time between overhauls) published by the manufacturer. What most overlook is that the engine lifetime is actually listed in hours of use AND years. Our C-75 / C-85 engines have a TBO of 1800 hours of use OR 12 years whichever comes first. I bet you find that engines that make it all the way to the 1800 hours are most often those used frequently. I've heard of a few engines that were used daily going for double the TBO number of hours with no problems. I'd also bet that 80% (WAG) of the engines in the Coupe fleet have more than 12 years since major overhaul. Thus, some of them have needed a top overhaul along the way. Our C-75 / C-85 engines are substantially the same engine as was used on about half the small, two-place planes from 1939 up through today. Their overall robustness has stood up very well. As you look for a plane, here are some engine things that I, as a pilot (not a mechanic), would look for: 1. When was it last overhauled in years and hours of use? 2. When the last major overhaul was done, was it done by a good mechanic or shop? (This may be impossible to determine.) 3. Was the last overhaul done to "serviceable" specifications or to "factory new" specifications? I paid extra for my engine to be overhauled to factory new specs in 1984. In spite of a period of storage in the middle, it is still flying safely with no engine problems in the mean time. 4. How many hours was the plane used a year? Low numbers may be a caution. Fifty plus hours are better. Seventy five hours a year, better yet. A hundred or more hours a year, great. But, let's get a better appraisal of this importance from mechanics rather than putting too much emphasis based on my thoughts. 5. Almost all Coupes have been in idle storage during some part of their history. If that storage has been in the last decade or two, especially recent, has a major overhaul been done since then? If not, what were the conditions of storage? The old "wisdom" was to start the engine for a few minutes each week to re-coat the cylinders and stuff with oil. Newer "wisdom" contains the recommendation that less corrosion will take place if the engine is not started unless it's going to be running about 45 minutes at operating temperature to evaporate any moisture from the oil. In short, if you aren't going to run it long enough to evaporate that moisture, it's better it not be started at all, even if it isn't pickled. Sealing the intakes when idle is better. Pickling is best. Ed Ed Burkhead http://edburkhead/Ercoupe/index.htm ed -at- edburkh???ead . com (change -at- to @ and remove ??? and spaces)
