From the outside looking in, it’s hard to tell G2 from its G1 predecessor, which, like its piston-powered first-generation ancestors, was never referred to as G1 until G2 came around. The big tell is the paint scheme. As Cirrus does with new model year introductions, the SF50 G2 features an updated paint scheme, though it’s not a big enough departure from last year’s model to immediately attract note. Physically, the biggest change is to the wing, which is a clean shape now, having discarded the aerodynamic fences, one per wing, between the ailerons and flaps and chucked the VG over the shoulder, as well. These aerodynamic changes are hardly revolutionary, though it’s hard not to like the absence of VGs.
With the G2, Cirrus has improved the plane in multiple ways, and not just by adding the Garmin autothrottles (which I’d flown before on a couple of Citations, including the now-discontinued Citation X+, perhaps the coolest airplane in my logbook). In addition to cleaning up the wing, Cirrus also worked with engine maker Williams International to turn up the wick on the FJ-33 turbofan above 24,000 feet (essentially by upping the allowable temps) so the jet can climb faster to its new RVSM ceiling of 31,000 feet. RVSM, as not all small plane pilots know, is short for Reduced Vertical Separation Minimums. The regulation, which has been on the books for more than 20 years now, lets planes fly from Flight Levels 290 to 410 with a thousand feet of vertical separation instead of the previous 2,000 feet. The RVSM update was the happy result of Cirrus engineers beginning to put their attention to the added altitudes and the FAA realizing that with ADS-B, RVSM standards were easier to maintain, so it could relax its technical standards for the approvals.
This upgrade to FL310 deserves special note. Adding a few additional usable altitudes might not sound like a big deal, but it is. Turbine engines, including turboprops and turbofans (like the Williams FJ-33), have a couple of sweet spot altitudes, one where the plane gets its best forward speed and the other where it gets its best range. The reasons for this are two. Jet engines use less fuel the higher they climb, and any airplane flies more efficiently in less-dense air, which happens as you climb. That’s why you sometimes hear pilots concerned about not getting cleared to a higher altitude…they can go plenty fast down low, but they burn a considerable amount of fuel while doing so.
So by adding an additional few thousand feet to the SF-50’s ceiling, Cirrus has given its jet pilots new options, and not just a few. The tradeoff in jets is always between loading and range, among other factors, of course. But when you reduce to these two main factors, you at least get a rough idea of what the mission profile looks like and if it’s doable. The two big, interrelated questions are, how much fuel can you take and how much payload can you add in passengers and cargo? By flying at its new ceiling of 31,000 feet, available only on eastbound flights, of course, the SF50 can go about the same speed as the G1 model used to be able to hit but while burning much less fuel. In other words, more capacity and more utility.
The improved speed profile is due to the engine putting out more power above FL240, which was simply an engine software change. This change does two things: giving pilots more speed at the previous lower altitude ceiling and giving it about the same speed as the previous top speed (around 305 knots true) at its new higher altitude. We actually got a little better than that, so Cirrus is over delivering in this case. This allows the jet to stretch its range by as much as 150 nm, a very substantial increase. With lower fuel loads, the jet can, conversely, carry more weight, about 150 pounds, so another person or a couple good-sized dogs.
The added oomph also allows the jet to go faster at its previous ceiling of FL 280—we had it up to 317 knots true at that altitude. So pilots, in addition to going farther for the same fuel, or the same distance for less fuel, also can choose to get there faster by burning more fuel. The difference in fuel burn we saw on our flight was less than 10 gph compared to the G1 model’s fuel burn at a cruise speed about 12 knots slower.