The climb rate with the -K model was noticeably better. On takeoff and climb the additional power does good things for performance, with better acceleration and very strong initial rates of climb. And as you climb to altitude, the benefit continues, as you're able to hold a little more power every step of the way. Based on my flight, at 8,000 feet, for example, we were producing the kind of power the Tornado Alley conversion would produce at around 7,000 feet.
As you might expect, the new engine uses more avgas on climb, but not by a lot. We were looking at a fuel flow of around 38 gph, which is about right for the additional 10 to 20 hp — the horsepower figure is a guess. But it is Continental's policy to provide an engine that is sure to produce rated horsepower, a trick it achieves by building its engines to produce a good deal more than rated horsepower. We maintained 1,200 fpm at 130 knots up through 8,000 feet and then between 800 and 900 fpm up through 16,500 feet. So even though the airplane is burning three or four gallons more per hour in the climb, it's climbing faster, which cuts down on the amount of time you're running the engine at max fuel flow.
This higher fuel burn does reduce the published endurance, but only by a few minutes. Mostly because of the increase in climb fuel burn, the max range for the SR22T is about 100 miles less than the Tornado Alley engine's. In some cases, that might present a reduction in utility. For those pilots like me who religiously pad their fuel reserves, it will have less impact.
Once we leveled off at 16,500 feet, I got to see what the performance differences are in cruise, and as far as I can tell, the SR22T is a little faster than the previous model while burning slightly more fuel, or as fast while burning slightly less. At 16,500 feet and at the same fuel flow as the Tornado Alley airplane, the new airplane was truing 195 knots, which is a little faster than before. When you pull the power back a little, to 14.5 gph, we were still seeing an impressive 185 knots true at that altitude. And at 13 gph, the true airspeed was still 172 knots. The Tornado Alley airplane, for the record, also has excellent performance at economy settings.
As I mentioned, one of the big benefits of the Tornado Alley system is its simple leaning procedures. Sensitive to that, Cirrus worked hard to make the -K model engine just as easy to manage, and it succeeded. When you level off in the SR22T, you reduce manifold pressure gradually, and as you do, the green arc expands and a blue line appears, indicating the proper lean of peak fuel setting. Just lean until the indicator matches up with the blue line, and you're done.
The last benefit Cirrus talks about for the new engine is improved descents, thanks apparently to a different default prop-pitch setting when you pull the power back. The difference is noticeable but hardly required; it's not particularly difficult to manage descent speeds to begin with.
Future Fuels, Current Controversy
The introduction by Cirrus of the new engine brought with it some controversy. As you might know, there's a coalition of users, the Clean 100 Octane Coalition, which is pushing for future aircraft fuel to be 100 octane and not some lower number. One current frontrunner, 94UL, is essentially 100LL without the lead.
Some coalition members see Cirrus' introduction of the new model as a capitulation to the 94UL movement, a claim that Cirrus denies. Bergwall told me that the company is not taking a position on a future fuel but is simply trying to provide future flexibility for its customers.
The criticisms seem to me more political posturing than anything having to do with the science. The Dash-K engine, after all, will surely work fine on whatever future 100UL fuels emerge, if any. In fact, it will probably work better than higher compression engines will, because it has better detonation margins and is more tolerant of impurities.
I've got quite a bit of time in Cirrus airplanes, and I currently lease a share of a PlaneSmart Aviation SR22 G3 Turbo. I love the airplane - and the provider - and have been very happy with the Tornado Alley engine.
That said, I like the new SR22T even better. Perhaps this is the big reason why, in early voting, Cirrus customers are overwhelmingly choosing the factory turbocharged model over the Tornado Alley conversion, a trend that I would expect to continue.
The big factors for me are the lower engine rpm, which make the airplane smoother and quieter, the smoother throttle operation and the improved takeoff and climb performance. These are not huge differences, but they are important differences.
A larger differentiator to me is the subtle feeling that the new engine imparts on the SR22. With the TSIO-550-K, the SR22 is a simpler, more elegant and better integrated product. These are traits that Cirrus has worked hard for years to build into its flagship, refining it to the point that it can proudly call the airplane a "mature" product in, of course, the very best sense of the word.