Okay, good, you're an engine expert.
So you have said.
So perhaps you can enlighten me on something...
I'll do my best.
Let's talk about Piper Mirage's with the Lycoming TIO-540-AE2A.
Sure, why not. I have a lot of time running and working with those engines.
Assuming that the owner treats it well (never lets CHT's exceed 385 F, etc), and keeps it well maintained, why would a Piper Mirage be any harder on an engine versus another plane with a Lycoming 540? The engine doesn't know what plane it is installed in... My understanding is that the early malibus and then the first mirages both had issues with engine performance that were subsequently fixed (mostly due to training issues and how to operate the engines for the continentals, then quality control crankshaft issues for the first Lycomings). Can you tell me what specifically is in the design of the plane itself somewhere causes engines to eat themselves as is alleged time and time again?
There are multiple aspects to your question. We'll look at the engine first. Although there are many Lycoming engines that are, in fact, 540s, there are also a number of differences between the TIO-540-AE2A and other 540s. Even if we separate out only TIO-540s, the TIO-540-AE2A is different than most other TIO-540s out there in several ways: it uses two small turbos (as opposed to the large single turbo that is typically used by Lycomings) with a single wastegate, has a TIT limit of 1750F instead of the 1650F standard on most Lycomings, and has twin intercoolers. It also has traditional angle valve cylinders in comparison to the Navajos, which utilize an updraft cooling cross-flow cylinder. So, the engine itself isn't the same as a another TIO-540 (or other 540) engine to start off.
To answer your question about what in the plane makes it more stressed than another aircraft, that comes down to how the aircraft is used. A pressurized piston single takes a lot of strain on the engine. The turbos are working harder to feed the pressurization (which means more backpressure in the exhaust and hotter outlet temps from the turbo), and the plane is also flown higher, which means the turbos are working harder to provide the higher pressure ratio required to feed that same manifold pressure and cabin pressurization. When was the last time you saw a Navajo in the flight levels? The highest I ever flew one was 17,500, and the only reason I did that was to say I did it. In normal flying, the highest I ever went was 12,000. You might say the intercoolers make up for that, and they do help, but that still results in a bunch of high pressures and temperatures within the combustion chamber and exhaust that go beyond what the CHTs tell you. We've also seen this on Continentals, look at the SR22 Turbo, which is known for cylinder issues, much like the Malibu. You might say "But wait, what about the Matrix? It's not pressurized." That is correct, but I recall being told (perhaps incorrectly) that it still has the sonic nozzles for cabin pressurization on the engine, they just feed the outside air. The reason for keeping those on has to do with certification. Both Malibu Mirage and Malibu Matrix use the TIO-540-AE2A, which was certified with sonic nozzles. If the Matrix used an AE2B (hypothetical engine name, not a real engine that I know of) without sonic nozzles, Lycoming would have to re-run some testing and do a bunch of paperwork, and that costs time and money. If someone can show me I'm wrong, then I rescind that statement.
Going back to the engine issues that were fixed, the Lycoming crank issue impacted multiple engine lines and certainly was not Malibu specific. As I understand it, the early Continental engine issues were much pilot error due to running them improperly, but Wayne Bower talked about his Continental-powered Malibu breaking a crank after running the engine as specified from somewhere in the flight levels. His partner had an uneventful dead-stick landing to an airport, and they sold the plane. So, who knows if the engines really are better. The plane is still demanding a lot out of the engine via pressurization and higher rate of high pressure ratios on the turbos, still with high power settings. Where do most Malibu owners run? I don't know, but I don't think it's at 65% power.
However, this then gets into an answer about the aircraft and pilots that is much the same as your structural failure point. If a pilot treats the engine right, there's no reason why it won't be reliable. But history has shown that pilots don't always treat the engine right, and that means when you buy a used Malibu, it has the baggage left by its previous owner in terms of engine treatment. If you had an owner who said "Oh, the limit is 1750F on TIT, I'll just lean right to that", then you can expect to have an unreliable engine.
Similarly with the wings falling off the plane, I recall reading the outcome of the testing after several in-flight breakups on Malibus had occurred, and it seemed that they hadn't found an inherent problem with the aircraft. My guess is that it more likely had to do with pilots going too fast (especially thinking about a dive from high altitude) and exerting too high of forces or getting into bad turbulence, flying into bad weather at high altitude (which is probably really bad), or ending up in a disorientation situation and then pulling too hard on the yoke at some point and severely overstressing the plane. But you've probably researched this more than I have.
Hope that is a sane enough answer.
Hope that is a sane enough question
Hey, you're the one who called yourself insane. I'm just going on what you've told me.
