Is it sense or stubbornness? Dassault, not surprisingly, says it’s the smart move. For the same reasons a three-engine airliner makes sense, a bizjet with three engines does as well. In addition to having added redundancy and safer engine-out handling manners, a three-engine airplane has better one-engine-out range characteristics, which is really important when that airplane is flying over the middle of an ocean — or somewhat before or after the middle — when it loses an engine. Having two-thirds of your engines left to “limp” home on is greatly preferable to having just half of your engines left to do that same job. Not to mention its noteworthy engine-out climb performance — again, the two-thirds rule — and its impressive hot-and-high and short-field takeoff performance. Finally, whereas an airliner can be counted on to fly to a handful of destinations throughout its air transport life, for bizjets, variety is the rule, and three engines, great short-field capability and exceptional hot-and-high performance all fit this profile perfectly.
Apart from its triengine design, the defining features of the new 900LX are its winglets, new to the 900 series, and its upgraded avionics suite, the EASy II cockpit. Based on Dassault’s EASy cockpit take on Honeywell’s Primus Epic suite, EASy II adds a great deal of capability while also improving upon the basic functionality of the system, which shows Dassault’s interest not just in fielding a product but in constantly improving it as well.
The winglets were designed by Aviation Partners, which seems to have perfected the art of taking a wingtip and turning it upward. The idea behind winglets is compellingly simple. Winglets do two main things. First, they effectively extend the span of the wing and, hence, its lifting capacity, while not greatly extending the lateral span of it. The second is equally important. Winglets properly designed, and the proof is in the numbers, keep the better part of the spanwise flow from being lost over the tips, thereby cutting drag and improving range and/or fuel efficiency.
The net effect of the winglets on the 900LX is an increase in range of 200 nautical miles, which, in a world in which the ability to travel back and forth between important city pairs is a critical piece of the buying equation, is a huge improvement. The model also comes with an increase in maximum takeoff weight and with some additional fuel capacity as well. The bottom line is that the 900LX can go farther on less fuel while carrying about the same load. As I said, it’s a tough gift to pass up, and Dassault hasn’t.
