Cirrus' second production model is stronger, heavier and faster than its sibling, but the SR22 is more than just a power upgrade words and photographs
DAVE HIGDON / TAMPA
Flying Cirrus Design's new SR22 light aircraft above the south-east edge of the Tampa, Florida, airspace, my eyes scanned for traffic while my mind scanned for something about the aircraft that was eluding me. By the end of an afternoon spent with the company's second production model, it became clear: the SR22 amounts to a completely different model, not simply an SR20 on steroids.
Experience prompted me to assume there would be a down side to simply hanging more horsepower on the front of an otherwise well-balanced aircraft. But no comparison between the SR20 and SR22 is really valid because the aircraft differ in significant ways.
Cirrus has executed an evolutionary step in the SR22 that goes beyond a simple 55% horsepower boost. Using the roomy four-place fuselage of the SR20 as the starting point, the company has created a machine that is stronger, heavier and faster.
But in producing this brawnier model, Cirrus has sacrificed neither the harmony and balance, nor the stability and sensitivity that makes the original a speedy, solid aircraft - accessible to the novice yet satisfying for the veteran.
Demands average skills
The 230kW (310hp) SR22 delivers more in payload and performance than the 150kW SR20, but without including characteristics that might worry less experienced pilots. The flying demands fall within the realm of any private pilot with average skills: if only this was true of some of the older high-performance designs generally flown by the average weekend pilot.
That said, it takes more than entry-level experience to execute and appreciate all that the SR22 offers. Couple novice-friendly ease of handling with its advanced systems and hardware, and you have an aircraft capable of making instrument flight level easier.
According to Alan Klapmeier, who with brother Dale gave life to Cirrus Design in the late 1980s, the design goal for the SR22 was to produce a growth model matching the best-in-class capabilities of its SR20. But the SR22 would be its own aircraft, and more than just a horsepower upgrade, Klapmeier said when he confirmed the programme in April 1999, only a few months after winning SR20 certification in October 1998.
Cirrus has been true to Klapmeier's word. Differences between the models abound - aside from the obvious engine difference. The SR22 uses Teledyne Continental's 230kW IO-550, while the SR20 has a 150kW IO-360.
The company made a couple of significant changes to the wing for the SR22 - some visible, others not. Inside, the main spar received about 18kg (40lb) of structural strengthening to better handle the aircraft's 1,544kg gross weight. Outside, a pair of 0.45m (18in) wingtip extensions increase the SR22's span to 11.7m - about 1m longer than the SR20's. The wing also attaches to the fuselage about 8cm further back to counter the higher weight of the more-powerful Continental and its three-blade Hartzell propeller. Taller landing gear raises the SR22 by about 8cm to increase ground clearance for the 2m-diameter propeller.
Just ahead of each wing root, Cirrus engineers have mounted a vortex generator (VG)on the fuselage. This improves low-speed handling by keeping air flowing over the wing at high angles of attack. The VGs stop working just above stall speed, allowing stalls to begin at the wing root and move outboard toward the tips.
Cirrus has also given the SR22 dual 24V electrical systems - primary and back-up - to reliably power a panel devoid of air-driven gyro instruments. It has no vacuum system, instead relying on an all-electric panel - another difference from the SR20.
The electrical system consists of two alternators, two regulators, two batteries and two electrical buses - primary and essential. In the unlikely loss of the main alternator, main battery and secondary alternator, the number two battery will deliver about 45min of power to the essential bus. The latter carries the electrically powered attitude indicator, turn co-ordinator, S-Tec System Fifty Five X autopilot, and the primary nav/com - in this case, Garmin International's GNS 430, with instrument flight rules GPS, VHF transceiver, and VOR/ILS receiver.
For an active private pilot who regularly endures serious instrument conditions, the SR22's multiply-redundant electrical system and all-electric panel seem more comforting than a combination electrical/vacuum system. Aircraft with redundant suction sources seldom also possess an electrical system back-up.
The combination of differences results in a typically equipped SR22 weighing about 1,020kg (2,250lb) - about 135kg more than its stablemate. At its 1,540kg gross weight, that same typically equipped SR22 can carry a full 318litres (84USgal) of fuel, plus about 300kg of passengers and baggage - sufficient for two adults, a couple of children, and light luggage for a trip.
On a typical 800km (500nm) flight, no one should feel squeezed or claustrophobic thanks to a spacious cabin with ample rear-seat leg room and generous 32ft3 (0.9m3) luggage space with 60kg capacity.
With full fuel plus reserves, the SR22 can cover about 650nm (1,200km) in about 3.5h of cruising on the high side of 180kt (330km/h) true airspeed. Interestingly, the approximately 68litres/h fuel consumption at 75% power gives the SR22 a range about 80km less than that of the 160kt SR20, which can eke out 700nm on 230litres, and the time difference is about 45min.
Of course, the SR20 can carry only about 260kg of payload with full fuel - but, with its 42litres/h efficiency, leaving a few litres behind lets the SR20 pilot pretty much match the SR22's full-fuel payload, but not the ground it covers in the same time. And covering ground is where the SR22 shines.
Getting started
With its fixed-gear simplicity and savvy design, pre-flight inspection of the SR22 takes as little effort as with any other simple aircraft. Check all the normal, logical spots - fuel tanks, engine oil, wheels, tyres, brake lines, control-surface hinges, lights, antennas - and it is ready to board. Despite its tall stance, a pair of fixed steps attached to the fuselage just aft of the wing trailing edge makes boarding relatively easy. White-tinted non-skid surfaces provide foot traction on a wing that elsewhere advertises a slippery nature with its gleaming seamless shine.
Once inside, you can see the Cirrus designers have placed virtually everything the pilot needs to touch within reach of the left seat - starting with the main switch panel, conveniently located on a horizontal surface on the bottom of the panel directly ahead of the pilot. The master switch, avionics switch, back-up electrical system and fuel boost-pump controls are wide rocker switches, both easy to read and operate. On the right side of this panel surface are dimmers for the interior lights.
Rock the fuel-pump switch back to its primer setting; when fuel flows stop the prime function and turn the key. Once the engine fires, advance the mixture to full rich, set the power at idle and the aircraft is up and running. Flick the avionics master switch and on comes the large Arnav multifunction display that dominates the centre of the panel.
Cirrus has stacked the avionics directly below the display, in a sports-car-like centre console - in this case the S-Tec 55X autopilot, Garmin GTX-327 transponder, audio panel and two GNS-430s. Tucked out of sight, but capable of making its presence known on either the Arnav or one of the Garmins, sits the sensor box for Goodrich's WX500 Stormscope. (The same company's Skywatch active traffic alert system is expected to be offered as an option). Throw in a Sandel 8803 electronic horizontal situation/radio magnetic indicator and the panel is complete.
While the engine temperature heads for the green, the pilot starts through the checklist, programs flight details into one of the Garmins, gets clearance and calls for permission to taxi. The final thing to do before releasing the parking brake is to open an overhead cover and remove the safety pin from a safety system that makes the SR200 and 22 unique: the Cirrus Airframe Parachute System (CAPS).
Made by Ballistic Recovery Systems (BRS) in South St Paul, Minnesota, the CAPS uses a small rocket motor that, on firing, breaks through a thin fuselage membrane and drags the emergency recovery parachute from its container.
Parachute deployment
Handle pull to full line stretch takes about 1.5s; full parachute deployment comes in another 2s, making the total process extremely fast. The deployed canopy lowers the aircraft at about 520m/min. The gear deforms then the seats crush, as designed, leaving an impact force on occupants that should allow them to walk away - sore, but otherwise uninjured. The aircraft will be considered written off by insurers. Although more than 100 BRS recovery-parachute "saves" have been documented on ultralights, experimental aircraft and hang gliders, to date there have been no in-service CAPS deployments.
The engine warm, and the CAPS armed, it was time to taxi to Runway 27 at Plant City, Florida.With me in the aircraft was Cirrus' chief test pilot Gary Black.
Taxiing the SR22 requires adapting to differential breaking, since the SR22 and SR20 share castoring nosewheels. The SR22 responds about as easily and quickly as the SR20, which surprised me, considering the higher weight of the IO-550 up front. Once we reached about 20kt, the rudder became effective enough to reduce the need to tap a brake to change direction.
Turning on to the runway, I used the "coolie hat" thumb control on top of the side yoke to set pitch trim a bit nose-up of neutral, centre the aileron trim and check the separate rudder trim was also neutral.
Advancing the single power lever to full throttle brought the big Continental engine up to a roar at its 2,700rpm redline, and in an instant, the SR22 began to accelerate along the runway.
In about 13s, the airspeed indicator passed 70kt and the SR22 lifted smoothly off the pavement. The aircraft continued to accelerate toward 100kt where, even in the humid 85íF (29íC) of this warm Florida evening, the vertical speed indicator (VSI) swung aggressively to more than 1,500ft/ min (7.6m/s).
Before we crossed the departure end of the runway, I pulled the power lever back to a detent and the engine fell to 2,500rpm; with a bit of trim, I pitched the nose down to achieve about 120kt and watched the VSI fall back to 1,000ft/min. Dropping the nose gave a good view ahead.
Turning south to avoid Tampa's airspace needed virtually no rudder input, even as we continued to climb. When the time came to level at 7,500ft, the SR22 still had plenty of four-figure climb performance left. Later, in extrapolating the day's conditions to those more typical for summer in the western USA, it was found that the SR22 should still deliver climb rates in the high three figures to altitudes in the middle teens.
With the power lever pulled back through the detent, I found a spot that gave me about 2,400rpm and 580mm of manifold pressure - about 75% power. Leaning fuel flow down toward 4.3litres/ min brought true airspeed up to 183kt; leaning the engine past peak exhaust gas temperature (EGT) dropped fuel consumption into the 1litre/min range, and airspeed to about 170kt.
Using lower fuel flows helps extend range, but the higher level better assures the engine cooling needed to get the powerplant to its advertised 1,700h time between overhauls.
Either way, managing the engine is simpler than in comparable aircraft, thanks to the single-lever control for power and rpm. The pilot applies full power and full rpm when advancing the lever fully forward. Pulling back to the first detent he reduces rpm to 2,500, then to about 2,400rpm before dropping manifold pressure to the next stop. Beyond the last stop, retarding the power lever lowers engine rpm and manifold pressure simultaneously.
That leaves only mixture control to worry about between cruise and descent. And the combination of exhaust gas temperature and fuel-flow instruments make its easy to find the sweet spot on the rich side of peak EGT.
Slowing the SR22 takes a bit more advance planning and some familiarity with the aircraft - a result of its slippery nature. This is an aircraft that cruises easily with the fastest of its power class - and does it with fixed gear.
With fairly low limiting speeds for flap deployment - 119kt indicated airspeed for the first 16í - some pilots may need to log extra time learning to make descents correctly. But flying the SR22 slowly gives no need for caution about maintaining control, even in the briskest crosswinds. Like its lighter sibling, the SR22 has handling traits that shine regardless of which end of its envelope it is being flown in.
Altitude holding
At high-speed cruise, trim controls for all three axes allow the pilot to dial the SR22 into level flight in a variety of conditions. Once trimmed, the aircraft fights hard to hold that attitude - even without the benefit of the autopilot. With the autopilot engaged, the pilot can track a heading, VOR radial or GPS-generated course, hold altitude, control climbs and descents, and fly coupled approaches.
At the low-speed end of the envelope, the SR22 requires work to stall, whether clean (no flap) or with a full 32í of flap. I reduced power and trimming to hold altitude until the engine reached idle. With the trim full aft (nose up), the SR22 still wanted to fly until I applied further aft pressure on the side yoke.
Finally, the stall horn sounded and the SR22 began a series of oscillations that started when the nose dropped at about 53kt indicated airspeed. The aircraft settled into a mush that accelerated to about 3.8m/s before the nose started to rise again and reduced the descent rate to 2.8m/s.
During the 20s or so that I held this stall, the SR22 remained almost fully controllable. Aileron input allowed levelling of the wings and prevented any hint of wing fall-off. The rudder also helped to maintain heading control as the nose bobbed up and down, porpoise-like.
A major adaptation problem came during a series of touch-and-go manoeuvres back at Plant City. Thanks to its taller gear and the high nose-up attitude that comes at the stall, the aircraft started to flare a bit too high on one pass, and not soon enough on the next. By my third try, however, the problem eased.
All of these approaches occurred with a brisk crosswind that varied between 30í and 40í off the nose. But on touchdown each time, rudder alone was more than ample to hold the SR22 straight on the runway centreline.
Solid contender
Cirrus brings to the light aircraft market another solid contender in the SR22, and one that is more sophisticated and capable than the SR20. For a heavy user of general aviation, the SR22's additional strengths will be hard to ignore for its price.
Only one other aircraft in this power class comes close, and that is Lancair's Columbia 300, another Continental-powered composite-airframe design. The Columbia may be a few knots faster, but it lacks the emergency parachute system and costs about 12% more.
Cessna's 206 Stationair cannot touch the SR22's speed, but carries more - and costs more. The Raytheon Beech Bonanza A36 and Commander 114 cost far more - almost double, in the Bonanza's case - and give away more than 20kt in speed despite having retractable gear. This puts the SR22 at the bottom of its class, price-wise, but near the top in performance, sophistication and user-friendliness.
If Cirrus Design became a threat to established general-aviation aircraft manufacturers when the SR20 came along - offering an aircraft with more speed on less power for less money in its power class - the SR22 is a double threat: both to the high-power aircraft in its horsepower class, and to some lower-powered aircraft in its price range.
Source: Flight International
