Plane & Pilot
Tuesday, July 26, 2011

Skylane For The Flight Levels


A turbo benefits far more than high-altitude cruise


The simple truth is that turbocharging without pressurization only does half the job. Surveys by a variety of manufacturers have revealed that pilots who own turbocharged, unpressurized airplanes rarely fly above 12,500/13,500 feet because of the inconveniences and cost of supplemental oxygen. Since there's no real penalty of flying high in a pressurized airplane, pilots operating inflatable models are more likely to cruise at 16,500-17,500, or higher where supplemental O2 is mandatory.

Semi-high may be good enough. At 13,500 feet, the Skylane TC delivers probably 15-20 knots better cruise than the normally aspirated model. That equates to 160 knots if you're doing everything right—airplane properly trimmed, ball in the center, cowl flaps closed, etc.

Pilots rarely come to grief because their airplanes are too slow, but lack of climb performance can be a major problem. In this case, the overriding benefit of the turbo is the ability to jump up to tall heights without breaking a sweat; then, transition to taller altitudes expeditiously if there's a need. Many of us have been in the uncomfortable situation of being nearly topped out in altitude while clouds ahead continue to climb faster than we can keep up with them. That won't happen as often with a turbo providing compressed power.

Both the normally aspirated and heavy-breathing Skylanes start off with about 1,000 fpm climb at sea level gross, but the turbo version begins to outdistance the standard model after the first mile of ascent. The turbo airplane loses only 150 fpm in the initial 10,000 feet of climb, whereas the standard Skylane leaves behind half its vertical performance in the same distance. In fact, the Skylane TC still scores 700 fpm climb when the normally aspirated airplane is at its service ceiling, 18,000 feet.

Critical altitude, the maximum height at which the turbo can still deliver sea-level power, is a full 20,000 feet with the T182. This means you can still plan on having 75% available for cruise at FL200. If you're willing to climb the airplane to the Skylane TC's maximum operating altitude, you'll see about 165 knots on 16 gph.

(Max operating altitude, incidentally, isn't the same as service ceiling. The latter is defined by performance, the height at which climb is down to 100 fpm on a single-engine airplane. Maximum operating altitude is more typically designated because of system or other limitations. In fact, the Skylane TC will still climb at better than 600 fpm at 20,000 feet.)

Either the standard or turbo 182 fly as you might expect for a 3,100-pound Cessna. Roll response is slow and deliberate rather than quick and reactive. The Skylane TC handles more like the six-place Stationair than its little brother, the Skyhawk. Elevator trim seems disproportionately heavy if you're stepping up from a 172, but the universal solution is to keep the pitch trim moving to neutralize elevator pressure as much as possible.

That's especially important in the pattern. A Skylane isn't as docile as a Skyhawk at low speeds, though you might not guess that by looking at stall speed. The 172S is almost a third of a ton lighter than the T182T at full gross, yet both airplanes use the same wing. The wing rules. Dirty stall is virtually the same—48 knots for the 172, 49 knots for the 182. That translates to good short-field takeoff performance for both models, just under 800 feet for the Skylane and about 950 feet for the Skyhawk. Landing characteristics are typical Cessna, docile and forgiving IF you keep the trim moving to offset the Skylane's 3,100 pounds.




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