Tuesday, September 21, 2010
Fixed-Gear Speed Demon
We fly the latest turbocharged Corvalis two years after Cessna bought the Columbia line of composite singles
A Continental TSIO-550C engine provides 310 horsepower on takeoff.
The Benefits Of Power
Both the Corvalis models are powered by essentially the same 550-cubic-inch Continental engine, and both are capable of generating 310 hp at sea level. With the benefit of twin turbochargers, however, the turbocharged TSIO-550C can maintain that power rating as high as 21,000 feet. That means the Corvalis TT can still produce its full 85 percent power at 25,000 feet.
Fortunately, the TT is a master at upward mobility. At 3,600 pounds gross with 310 horses out front, the Corvalis scrambles for altitude, scoring 1,400 fpm climb from sea level. Better still, the airplane holds on to good vertical velocity up high, an important factor for airplanes that must match the mountains. Try Leadville, Colo., elevation 9,927 feet, in the summertime in a normally aspirated airplane (or better still, don’t) and you’ll gain a full appreciation of the benefits of turbocharging.
The exact cruise speed of the Corvalis TT has been the subject of some debate. A few years ago, the original Columbia Aircraft went head-to-head with Mooney on which manufacturer had the fastest piston single. Mooney took the competition seriously enough to commission the LoPresti family to help them reduce drag and improve speed on the turbocharged Acclaim S.
There’s no longer much debate over which airplane is faster (it’s the Mooney), but there’s little question the Corvalis TT is the world’s fastest, FIXED-GEAR, piston-powered, production aircraft. Technically, the TT’s spec is 235 knots, but that’s on a flight-test airplane with no antennas, no boarding step, no TKS or air conditioning—in other words, an airplane with virtually nothing hanging out to grab the wind. Lancair COO Tom Bowen was VP of engineering at Columbia for several years, and he once told me he had seen 237 knots on a pure flight-test airplane.
You’re not likely to see cruise that fast in a typically equipped airplane, replete with a full raft of antennas and all the options that most pilots buy. Typically equipped airplanes that include most of the options above can score more like 225 knots at max cruise on a good day with all the pilot’s biorhythms on a high. I’ve taken two Columbia 400/Corvalis TT’s to FL250 for cruise checks, both times with a company pilot setting power and mixture, and I saw 222 knots and 228 knots, respectively, pretty impressive for an airplane with gear permanently down and laminated.
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Labels: Piston Singles