Payload figures will improve too. Because of the huge range of the airplane, you can leave off fuel and take along what people and bags you want to load aboard. Cozine commented that the Cessna 182 JT-A “uses so much less fuel that you can always take more payload than [on a] gas piston 182.” This will allow pilots to fill the seats while leaving off fuel, while still having plenty for long legs with good reserves.
As I said, power management is simpler than it is on a turboprop — set it and forget it. The power is controlled electronically — there is no mechanical linkage. The engine control unit (ECU) has a backup mechanical system (should some extremely unlikely system failure take out the ECU). The SMA engine, thanks in part to Cessna’s modifications to the system to help it run cooler and with better margins, ran so far within the limits despite the hot day (ISA+12) that it looked as though the needles were painted on the temperature gauges no matter what abuse we dished out.
That abuse included several scenarios not discussed in the POH, including extended slow flight, full power cruise at 12,000 feet and an engine shutdown in flight.
That last point is key, since one of the FAA’s big concerns about diesels is their stubbornness about getting back to business once they’ve been shut down for a time. In our case, we were loitering over a conveniently quiet and out-of-the-way Kansas airport, Kingman, when Charles gave me the OK to shut down the engine. Now, unlike with gas piston engines, which become immediately quiet after a shutdown, with a diesel engine the shutdown can seem like a gray area. To ensure the engine had indeed stopped doing its thing, I raised the nose and watched the rpm degrade, a good sign (or a bad sign, depending on whether you wanted to shut down or not). After a two-minute glide (it didn’t seem as long as that sounds), I tried the restart. I wish I could say it was a harrowing experience that will live with me forever, but the truth is far more pedestrian. The four-cylinder diesel immediately sprang to life and we were under power again. Ho-hum.
With 230 horses again at our disposal, we circled down to Kingman to do a couple of touch-and-goes. The first one, with full flaps, was uneventful. The speeds and feel were nothing different from what you’d experience in any Cessna 182. Such was not the case with minimum or no-flap approaches. The engine and Hartzell prop combination doesn’t yet have the same aerodynamic braking characteristics as in existing Skylane power plants. The result for now is that you need the flaps to get down to landing speeds. Cessna is working to reconfigure the details of the system (prop, software and power lever) to allow finer pitch for greater prop braking while on approach. Once that’s been done, it’s safe to say that the landing performance of the JT-A will be hard to discern from that of the gas piston Skylane, which is to say, excellent.
That might be the big lesson of the new model for Cessna. With a well-designed power plant, thoughtful integration of that engine into the new model, and patient development, even a legendary light airplane like the gas piston Cessna 182 can start using jet-A and can do so while enjoying the benefits of high fuel efficiency, single-lever power, readily available fuel and higher payloads, all features that are difficult or impossible to get with conventional light airplane power-plant technology.
View our Cessna 182 JT-A photo gallery.
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