The hope is that, as a product develops, it will mature. And I mean "mature" in the good way, you know, like expensive wine, fine Swiss watches and very fast airplanes, like the Cirrus SR22.
I was the first journalist to fly the original SR22, and I've flown every new one since, some of them for several hundred hours. Based on my experience in the airplane, I feel confident in saying that a new SR22 is a substantially better airplane in nearly every respect than the original. Most of that improvement has been incremental, with a few big exceptions, including the upgrade to the G3 model a few years back and the concurrent offering of the Turbo model, as well as the introduction of the Entegra and Perspective flight decks.
While largely invisible to the naked eye, the latest improvement, the upgrade to a Continental factory turbocharged engine, is also a big deal. The new engine, the Teledyne Continental TSIO-550-K, provides several very noteworthy quality-of-life, longevity and performance advantages over the Tornado Alley turbo-normalized engine and does it for the same price. Cirrus will continue to offer the Tornado Alley engine, so customers will be able to select the engine option that best suits their needs or tastes.
The new dash number is unique to Cirrus, at least for the time being. The previous engine, the IO-550-N, was converted by Tornado Alley Turbo from a naturally aspirated engine to a turbo. Tornado Alley also added its patented GAMIjectors to even out fuel flow and balance cylinder temperatures.
The new engine is a lower compression engine, 7.5:1 versus 8.5:1 for the Tornado Alley product. The lower compression means the -K model has slightly less efficient specific fuel consumption, but it also means it has better detonation margins. It's also covered by a Teledyne Continental factory warranty. Moreover, it also features balanced fuel injection. Continental just doesn't have a trade name for it.
While continuing to sell both products, Cirrus is talking about the new engine as a big upgrade. In a press release, Cirrus vice president Pat Waddick said, "In addition to a quieter operation, lower weight, a smoother ride and many other refinements, the new SR22T offers Cirrus customers a high performance, twin turbocharged option with the additional benefit of greater future fuel flexibility."
That last bit — "future fuel flexibility" — is the most intriguing and controversial part. More on that in a bit.
The new engine comes with new intercoolers, new NACA inlets, two big air filters and new louvers. The nose does look a bit different. A change unrelated to the engine is a newly designed nose gear, which features for the first time on a Cirrus an oleo strut, a change that owners will surely welcome and which could be adopted on other Cirrus models over time.
Time for a Change?
When Cirrus introduced the Turbo it made the unusual decision to go with the same naturally aspirated engine, the IO-550-N, that it had been using in the SR22 since the inception but to have it modified by aftermarket turbo specialist Tornado Alley under an STC. The airplane, the SR22 G3 Turbo, was a big hit, and the Tornado Alley mod seemed a great fit for the '22, providing excellent lean-of-peak fuel flows and remarkable ease of use for pilots. The system is dirt simple to operate. In most instances, you simply push the mixture and power levers full forward on takeoff and leave them there until you level off at your final altitude.
The Tornado Alley engine burns about 35 gallons per hour in the climb, though it climbs very strongly, so the total amount of time spent in climb is relatively low. Once you're at altitude, you simply do what Cirrus owners refer to as "the big pull," reducing the fuel flow to around 17.5 gph, which is the setting at which you cruise, and cruise plenty fast too, at better than 200 knots in the midteens and quite a bit faster in the 20s (where I very seldom fly). Engine management in the Tornado Alley engine is that simple.
So I was curious to see how the workload would be with the new engine. I have to admit that since I've been flying the G3 Turbo, I've gotten quite used to not having to fiddle with the mixture. You pretty much set it and forget it. Would the Continental turbo be more work?
I was also curious to see how the Continental engine would deliver on the other highly touted Tornado Alley benefit, more even cooling across the cylinders through its GAMIjectors. I've been impressed by the performance of the GAMIjectors, but to be honest, based on my flying a similar Conti engine last year, I suspected I'd find good cooling performance from the -K model as well.
Surprising Performance, Expected Ease
I wasn't expecting much of a difference in terms of performance from the new engine as I advanced the power on the '22T and began to roll down 17L at Austin Bergstrom, but I was surprised right off the bat. The SR22T accelerates more briskly than the G3 Turbo, and that's saying a lot.
In the seat was Cirrus product guru Matt Bergwall, who'd been doing a cross-continent stealth sales tour with the new airplane before its official launch and had amassed more than 30 hours in it since he'd left the Duluth, Minnesota, headquarters of Cirrus a week earlier.
In addition to the new get-up-and-go, also noticeable was the lack of cam action toward the end of the throttle travel. As you probably know, the 550 model that Cirrus uses has no prop control, though it does have a constant-speed prop. Instead of an independent lever control, it uses a cam actuator in the throttle to increase the prop pitch as you push the throttle toward the stop, increasing the prop revolutions per minute to its limit of 2,700.
The new SR22, on the other hand, is limited to 2,500 rpm, which is arguably the most important change with the new engine option. Push the throttle forward and you simply get more power without an attendant increase in rpm. I like that a lot.
The 2,500 rpm rating is great in many respects. It makes the airplane quieter both inside and outside the cockpit, it makes it feel noticeably smoother, and it will make it a better neighbor at noise-sensitive airports.
The rated power of the engine, 315 horses, is just five horsepower more than the previous engine has, but nobody thinks it produces just 315 hp. Based on certification quirks, the engine is given, Bergwall told me, a kind of worst-case-scenario rating. While not quoting numbers, Bergwall said the engine makes substantially more power than 315 hp, and that's why it performs a lot more than a couple of percentage points better than the Tornado Alley engine airplane.
