Plane & Pilot
Tuesday, June 21, 2011

Diamond DA40 XLS: Premier Edition

Premier Aircraft of Fort Lauderdale, Fla., has created its own ultra version of the Diamond DA40 XLS

The debate between advocates of side sticks, conventional center sticks and yokes will probably never be resolved, but my vote goes to center sticks. The DA40's stick is nicely harmonized between ailerons and elevator, with enough roll to make handling sporty without so much pitch that the airplane becomes twitchy. There's no slop in the Star's controls, as pushrods connect the controls to the stick.

Back in the pattern, the Star is happy at any approach speed between 65 and 80 knots. Dirty stall with flaps extended to their full 42-degree limit is a low 49 knots, so technically, you could meet the 1.2 Vs requirement with an approach at only 59 knots. That might be a little sporty unless you know the airplane VERY well, but 65 knots should provide a reasonable flare with plenty of roll control remaining.

That's assuming you could find a way to slow the airplane. Go-down/slow-down can be a definite challenge. Glide ratio is 11:1, half again the L/D of most fixed-gear singles. The smooth, composite construction and semi-sailplane, Wortmann FX 63-137 airfoil result in an unusually efficient design. Rough calculation suggests a drag coefficient on the order of .020, only slightly less efficient than the aerodynamic paragon of general aviation, the LoPresti Fury (at .0188). Max flap speed is 106 knots, so flaps don't help much during descents. The airplane could benefit from installation of speed brakes, not currently an option, and a difficult STC considering the Star's composite wing structure.

If descents are a challenge, landings are exactly the opposite, almost silly simple. You could probably coach Betty White through a solo in a half-dozen hours. The flare seems nearly automatic, and the touchdown is anticlimactic. Few airplanes are easier to land than a Cessna Skyhawk or Piper Archer, but the Diamond Star may be one of them.

Add it all up, and it all adds up. Every aircraft design represents a series of compromises, but the folks at Diamond seem to have compromised the least. The DA40 XLS gets my vote as the best, all-around, 180 hp, fixed-gear people hauler above the planet.

Diamond DA50 SuperStar

The Diamond SuperStar was a design exercise initiated in 2006 to explore the possibility of a fixed-gear, super-single based on the company's popular DA40 Star. The airplane employed a FADEC-managed, twin-turbocharged, 350 hp Continental TSIO-550J, and it was intended as a competitor with the Cirrus SR22, Columbia 400 and Mooney Acclaim. Diamond was riding high at the time with its DA20, DA40 and DA42 aircraft selling well, and the company hoped the new aircraft would give them a foothold on a new market.

The original concept was for two similar airplanes, the 350 hp SuperStar and a 170 hp Thielert diesel version, the Magnum, both to be certified with five seats. The SuperStar was expected to offer a flight-level cruise of 200 knots. Both projects were put on hold when the economy turned asthmatic in 2009. Diamond was concentrating its assets on developing the Diamond D-Jet at the time. With the recent success of the Cirrus SR22 and Cessna's acquisition of the Columbia line three years ago, Diamond may be taking the DA50 off the shelf in the next few years.


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