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The natural evolution of airplanes is to increase the power, and that is just what Cirrus Design has done with its new SR22. Where the original production Cirrus, the SR20, flies with a 200-horsepower IO-360 six-cylinder Continental, the SR22 has an IO-550 Continental six that develops 310 horsepower. That is a big increase.
Even though the two airplanes look alike, they are actually quite different. The 22 wing has more span, which, with its higher maximum takeoff weight, requires a larger and stronger wing spar. More horsepower meant more fuel and that, too, required an internal change in the wing. The longer wing and the increased weight (the SR22 maximum takeoff weight is 500 pounds greater, at 3,400 pounds) are said to enhance the landing qualities of the airplane, but after flying both, all I can say is that both are nice airplanes to land.
The angle of incidence of the horizontal tail was changed on the SR22 to retain flying qualities with the increased horsepower. The elevator horns were also changed.
A big change is in the electrical system. The SR22 is almost unique in being an all-electric airplane. There is no vacuum system. The Porsche-powered Mooney PFM is the only other contemporary all-electric single.
There are good reasons for the choice of electric power. One is that vacuum pumps have been a high warranty item. The other is the coming of full authority digital engine control, FADEC, currently being tested at Continental and almost ready. Because FADEC requires electrical power, there is a requirement for dual systems and enough power to operate the FADEC after any imaginable electrical problem-at least until the fuel is exhausted. This might be done with a standby battery, but the most logical way to do it is with a dual electrical system, a nice thing to have with or without FADEC.
The SR22 has two batteries, two alternators and two buses. Cirrus calls the systems primary and secondary though the secondary system might also be called the essential bus, running as it does the flight instruments and selected avionics. This system will also run the FADEC if it is blessed to do so by the FAA. The dual system will also facilitate the installation of a glassier cockpit than is now installed in the SR22.
In normal operations everything operates off the primary battery and alternator and both batteries are kept charged by a 60 amp, 28 volt alternator. The secondary alternator, 20 amps, will provide charging only to the secondary battery, which is also held in reserve should both alternators fail and the primary battery become discharged. The 20-amp secondary alternator is from B & C Specialties and is a high-quality unit that is approved in a number of other airplanes as a standby charging system.
The SR22 comes with a choice of avionics packages, and most buyers will probably opt for the top-of-the-line "B" configuration, which has the big Arnav ICDS-2000 multifunction display, dual Garmin GNS 430s, an S-Tec/Meggitt Fifty Five X autopilot with altitude preselect and control, a Sandel 3308 EHSI, plus a Garmin transponder and audio panel. It is a complete airplane with the only option a WX-500 Stormscope that plays through the multifunction display. Cirrus will have the Goodrich Skywatch collision avoidance system approved shortly and expects to add more options to play through the multifunction display.
Despite all this built-in capability, the SR22 is quite user friendly. The grouping of switches and controls is logical and the operation of everything reflects the company's determination to make the airplane as easy to operate as possible.
