Thanks Mike, but the Seneca I flew was a low time airplane and even though I used fairly high cruise settings (32" MP & 2400RPM) I was careful about cooling the engines down---same thing with the Skymaster with the same engines.
Early on, as a pilot in light recips for Cal Air Freight (now Ameriflight), I was taught to reduce power settings at the rate of 1" MP per minute to avoid cooling the cylinders too rapidly, and that formula or it's approximation works well. I try to plan descents so that I can trade altitude for power at that rate at least until the MP gets out of the turbo--around 20" or below. Gentle cooling techniques work wonders with any recip engine and even when I'm running a turbine I still don't just yank the throttles back---(not goin'ta do it!--wouldn't be prudent!---G Bush Sr)
You are right though about the Mixmaster being a maintenence hog though, but our new maintenence director has eliminated a lot of problems in the last year just by being very thorough on the 100 HR inspections. Our former MD, a shop out of Big Bear Airport, was a really nice guy but was extremely sloppy and we were constantly breaking down in the field which was duly noted by BLM. Since we switched mechanics, we have had zero problems and I finished the season last year with a perfect availability record.
One of the Skymaster's problem area is the gear, Hell, there are eleven (yes 11) hydraulic actuators in the gear system which just begs to be a pain in the butt and the rear engine on the non pressurized turbocharged ones tend to run a little hot so we I never run leaner than 100 degrees on the rich side of peak with them.
The Diamond twins you mentioned are certainly the wave of the future. The Thielert diesel equipped ones get better fuel economy than a lot of singles but it looks like single engine performance is kind of anemic with only 135 ponies per side, if they could increase that by 20 HP or so with the diesels, they'd really be a sparkling performer. Yeah, I know they also come with 180 HP Lycomings but there goes the fuel economy too.
With light jets, FADEC, avionics innovations, and new engine designs coming on line, you young pilots have a lot to look forward to and I envy you.
Maybe someday when you see some old coot leaning against the airport fence, you'll come over and offer me a ride in your new 400 MPH, hydrogen powered, six seat, aerobatic single---maybe you'll let me fondle the controls for a minute---maybe you'll even forgive me for fondling your girlfriend while I climbed into the airplane!!!!!!!
