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Editor's note: Thank goodness no one flies the SF260 over gross in Standard Category. My SF260W, which was experimental, could take off easily with a 3,000 lb gross. Take off speed was 75knots and the plane was not rock stable until it exceeded 130 knots, but it was easy to control and once the fuel in the tip tanks was gone it was easy to manage.
For those who simply can’t resist the urge to turn the airplane loose, the weight limit is 2205 pounds and both 19-gallon tip tanks must be empty, leaving a 26-gallon allowance in the main wing tanks. Apparently, the bending moment associated with the long arm to full tips puts undue stress on the wings. Fortunately, payload still works out about the same (319 pounds), and endurance is approximately an hour and a half, as long as most pilots can put up with acro, anyway.
Even at max gross weight, however, power loading is only 9.3 pounds/hp. (At the aerobatic weight limit, the figure is reduced to an even more impressive 8.5 lbs./ht.) Such a low number translates to a nice stab in the back at power up and good takeoff/climb performance, the latter better than just about any other production airplanes except the Pitts models. With a stall speed of 60 knots, the Marchetti demands 820 feet to lift off the runway, but once in the air and pointed uphill, it climbs remarkably well. Spec is 1800 fpm, and though that may be a bit optimistic, the real world 1500 to 1600 fpm is better than any other piston production single.
Frati’s airplanes are universally fast, and the SF-260 is certainly quicker than any other production model with comparable horsepower. The test airplane indicated an easy 184 knots with everything to the wall at 500 feet over the ocean, but no one flies that way. Patlin says a realistic cruise with two up front and full tanks at 7000 feet is 175 to 180 knots, and that’s well ahead of the Commander 11+D and the Trinidad. He flight plans the airplane for 170 knots block and rarely misses his ETAs. The Marchetti is also notably quicker than the Beech F33A Bonanza and, appropriately enough, the 200 hp Mooney MSE. (It’s interesting to note that Mooney’s new Ovation beats the Marchetti SF-260 by five to 10 knots but, of course, the Ovation has 20 more horsepower and isn’t legal for aerobatics.)
The SF-260’s small wing provides a relatively smooth ride in turbulence by reason of the fairly high-wing loading. At 22.3 pounds/square foot, the Marchetti’s loading is among the highest in the piston class. High-wing loading is a characteristic of many high-performance airplanes that punch through chop with minimum fuss. (Jet fighters such as the F-15 Eagle and F-4 Phantom score wing loading of 75 or even 117 pounds/square foot, and they can slice through extremely rough air with little problem.)
Though the SF-260 makes a quick cross-country airplane, it’s hard to imagine anyone buying one strictly as a traveling machine. The Marchetti was designed to fly, not just bore holes in the sky. Aerobatics seem only natural, not full-blown unlimited competition, but Saturday morning air show, wanna-be-Bob-Hoover maneuvers. Like the Falco before it, the SF-260 literally begs to be guided through a steady diet of rolls, loops, hammerheads and various other up, down and sideways antics. Stress limits are +6 and –3 Gs but, unless you have the full inverted Lycoming AEIO-540-D4A5E flight package, you won’t be pulling many G, outside maneuvers. A number of air combat schools across the country have selected the SF-20 as the airplane of choice for tail-chasing, and Walter Mitty fighter pilots love the quick control, enthusiastic power response and predictable handling.
Me, too. I flew N46Z three times for this story, once for the initial straight and level checkout with Bill, the second time for the air-to-air photo session with Patlin and the third flight with Lt. Com. Canin for aerobatics. Canin is an A-7/F-18 carrier pilot and graduate of the U.S. Navy Test Pilot School at Patuxent River, Md., and he has explored the Marchetti’s aerobatic envelope in-depth.
On the day of my final hop, the winter haze and fog abated just long enough for me to drive the SF-260 out over the water off Malibu, Calif., and get in a good hour of aerobatics. After a full stall series, I tried a half-dozen garden-variety aileron rolls left and right, followed by four-point and eight-point hesitation rolls. Pitch attitude for rolls can be as you like it, from the horizon to 40° above it with little nose drop at the completion of the maneuver.
Similarly, entry speed can range from 90 to 180 knots. Vertical tricks such as loops, Immelmanns, Cuban eights and hammerheads demand a four-G pull. Canin and I flew a little of everything, including a few maneuvers neither of us recognized. The final maneuver was a standard upright spin that popped out immediately upon unloading the stick and applying opposite rudder.
As a professional fighter pilot who loves his airplane’s responsive handling and enthusiastic performance, Canin offered an interesting proviso about flying the Marchetti in simulated air combat. “In some respects, this airplane is almost too good at what it does. The high roll rate, tight turn radius and light stick forces make the Marchetti a good infighter for air combat flying. I could certainly see how two good pilots who really anted to win could get into trouble,” he says.
“Eventually it would be almost like a knife fight in a phone booth, with both pilots pulling harder and harder, trying to get in closer for a decisive laser ‘kill.’ Both pilots could run out of airspeed, control and ideas all at the same time and in very close proximity to each other.”
Overall, the Marchetti is a remarkably easy flying airplane, however, almost a mind reader, with no nasty aerodynamic surprises, though it’s not totally without vice. Canin demonstrated the only maneuver he knew of that could result in an out-of-control condition, a slow, bottom rudder top aileron back elevator skid and, sure enough, the airplane eventually snapped under the bottom. At more normal speeds, roll rate is an easy 90° /second and pitch sensitivity is very quick, faster than most pilots are used to. A five-G pull demands only about 30 pounds of pressure, so stick force per G is very low. Level stall characteristics are fairly conventional with plenty of aerodynamic warning and steep angle, full power departure stalls hold no surprises, with a slow, gentle roll back toward the high wing.
Hold the SF-260 in a level, power-off stall, even in the clean configuration, and be prepared for a hellacious sink rate. I saw the VSI roll around to 3000 fpm down, presumably at the airplane’s 61-knot stall speed. That’s a 45-degree glideslope. Imagine what the descent would be with gear and flaps full down. Energy management is critical in this airplane. The SF260 is either flying or falling, and its up to the pilot to decide which.
That makes the SF-260 a power-on airplane in the pattern. With gear and flaps retracted at 90 knots, the glide ratio is a theoretical eight to one, but with gear and flaps extended, glidepath is probably less than half that. Limit speeds are low. The first 20° of flaps can go out at 125 knots, the last 30° at 108 knots (that’s right-there are 50 degrees of flaps) and the gear can be thrown to the wind at 105 knots. Canin and partners like to fly the Marchetti like a twin, maintaining 95 knots around the patch with power, slowing to 90 knots across the fence. High approach speeds, the need for power to cushion the flare and the short gear legs don’t make the Marchetti easy to land and it’s certainly not a short-field airplane.
Considering the price of admission and the airplane’s useful load and seating limitations, its not likely the SF260 will be taking over the United States market any time soon. Air combat schools love its handling and performance, if not its price. The Marchetti is an airplane designed for a fairly narrow, specific mission and not every pilot will be able to use its considerable talents.
Personally, if I ever win a really big Super Lotto, the Marchetti SF-260 has just become the seventh airplane on my list for must-have flying machines.
For more information, contact Mike Patlin, SF260 Association, 3538 Veteran Ave., Los Angeles, CA 90034 (310) 559-7131. P&P