Like just about everybody else, I first saw the Mooney Acclaim on the opening day at this year's Sun 'n Fun Fly-In, when Mooney unveiled it before a standing-room only crowd of aviation journalists and interested show-goers. The particular airplane that Mooney unveiled, N312TN, cut a striking figure on thegreen grass that sunny Florida morning, the airplane decked out dramatically in red and black with the image of an eagle, its wing extended in flight, cleverly worked into the scheme.
But it wasn't until Mooney CEO Gretchen Jahn, who'd just flown in nonstop from Texas, started talking numbers that people sat up and took notice. And the figure that got everyone's attention was for the high cruise speed-236 knots-which Jahn claimed to have achieved on the nonstop flight into Lakeland.
The 236 figure came as a bit of a surprise even to Mooney. Preliminary specifications only called for a 230-knot cruise, but on the trip out to Florida the true airspeed figures on the Garmin G1000 primary flight display were telling a faster tale, and a new story line was born. The Acclaim wasn't just going to be faster than any Mooney. It was going to be faster than any other piston-powered airplane in production. Or so it seemed.
The other contender to the fastest piston throne is the Columbia 400, another turbocharged airplane, though one significantly different in design from the Acclaim. With fixed-gear and composite construction, the Columbia 400 makes use of 310 horses, compared to the Acclaim's 280, to deliver its best cruise speed number, 235 knots. As is the case with the Acclaim, that kind of speed comes only at great heights, 25,000 feet, an altitude that few pilots are likely to fly on a regular basis in a nonpressurized airplane.
It's a common notion that the powerplant drives an airplane's design. In the case of the Acclaim, it's fair to say that the new powerplant, the Continental TSIO-550-G, is the Acclaim's design. The new engine allows the tried-and-true Mooney airframe to accelerate to the highest true airspeed ever for a production Mooney.
With the addition of the Continental engine, the Acclaim gets 10 more horsepower than the turbocharged Bravo, 280 compared with 270. The Acclaim replaces the Bravo in the Mooney lineup. The extra horsepower, combined with the new cowling, allow the Acclaim a gain of 15 knots over the Bravo (which also has a ceiling of 25,000 feet). And extra speed, as the jet crowd knows, means extra range. More on that in a bit.
The Acclaim is slightly different externally from other Mooneys, but the airframe basics from the firewall back remain the same.
The wingtips have what Mooney calls "mini-fins," slightly turned up wingtips, but if you're thinking that the aerodynamic advantage of such small tips has to be negligible, I'd have to agree. On the other hand, you've got to like the aesthetic boost they give the familiar design. Somehow this Mooney does look faster than its forebears. One change that's a lot more than cosmetic is a brand new cowling. The new cowl provides air cooling to the heavy-breathing TSIO-550 and eliminates the need for the cowl flaps that came on the Lycoming TSIO-540-powered Bravo. The new cowling features a pair of big annular inlets that channel the airflow to a center-located inlet that feeds the air to the engine compartment. The new air cooling scheme seems to be working well, which is always a major concern with turbocharged engines, which often run hot.
The Acclaim's new TSIO-550-G is derated to 280 hp, achieved by limiting manifold pressure. Mooney refers to the engine as being turbonormalized, but the distinction between turbonormalizing and turbocharging, if meaningful at all, is a subtle one. A widely accepted version of the term means that the turbo controller maintains the manifold pressure at standard sea level pressure, or 29.92 inches. But the Acclaim's engine is limited to 33.5 inches of manifold pressure, so a more accurate description might be just to say that the engine is turbocharged and features an automatic wastegate to keep the pilot from overboosting the engine.