Hello C.A. I flew a navajo on skydiving ops for over a year with no engine problems, thats not to say we didn't have other problems...
Power settings etc, if i can remember correctly were.
After takeoff 36' 2400rpm, and lean to approx 1400 egt for the whole climb.
Approaching the final run reduce power to 30 inches over about 1 min, then reduce rpm to 2200, this will reduce the manifild pressure to about 25'. Leaning the whole time to keep 1400egt.
Airspeed between 90 and 100 knots, jumpers away, close cowl flaps, descend at 180 knots at this same power setting.
Then i would descend to about 500 feet, pull the nose up to reduce airspeed, flap gear etc, join final push mixture to full, not to quickly of course, full rpm and land. If shutting down cool engines for 5 mins first, otherwise if continuing on, jumpers get on board and repeat the whole process.
This is the method we used, as i said no engine problems for the 3 years i worked at this drop zone. Some of the best times of my life.
