The 235-horsepower rating is maximum continuous, and the engine is a 540-cubic-inch Lycoming that, in other applications, develops a lot more horsepower. Thus Cessna feels justified in saying that it is OK to cruise at maximum continuous power with a full rich mixture if you wish. Sucking on oxygen and level at 13,000 feet, I calculated the true airspeed to be 165 knots on 25 gallons of fuel per hour.
I wouldn't care to run a turbocharged engine that was hooked to my checkbook at maximum continuous power all the time because of engine wear and fuel consumption. Turned down to 88 percent power the airplane would true 160 knots at 12,000 feet on about 17.5 gallons per hour. The specific fuel consumption at full throttle, full rich, or at 88 percent, leaned, is very high. Most users will probably find it a reliable 150-knot airplane at a reasonable fuel flow in the 10,000 to 12,000 foot range. When compared with the older Skylanes, which would true 143 knots on 12.3 gallons per hour, the new ones do seem to like their avgas.
The 88-gallon fuel supply would give good endurance except at the highest power settings. The airplane I flew had a useful load of 1,042 pounds and a full fuel payload of 514 pounds.
The maximum certified operating altitude of the Turbo Skylane is 20,000 feet, and the engine will still develop maximum continuous power at that altitude. The airplane will true a max of 170 knots at its certified ceiling.
With the prop turning a maximum of 2400 rpm the sound level isn't bad even at full bore. The vibration level is higher than it should be, though. That is true of some of the other new piston airplanes, and where I would put the management of vibration high on my list of things to do, the engineers working on these airplanes apparently don't agree. I'd give up some knots and/or pounds of useful load for a silky smooth ride any day.
The KAP 140 autopilot does a nice job of flying the Skylane though the one in this particular Skylane appeared lethargic in the heading mode. Switched to nav, though, it tracked with precision and did a smooth job of flying the airplane thanks to roll steering commands coming from the navigator. The autopilot altitude preselect and hold function is good and quite useful, though for climb and descent you must select vertical speed instead of just adjusting pitch attitude.