Sneak Preview: Dassault Falcon 5X

We reveal the secrets of this cutting-edge design, the first in a forthcoming lineup of next-generation Falcon jets.

Dassault Falcon 5X

Dassault Falcon 5X

** Dassault Falcon 5X**

A couple of weeks before the National Business Aviation Association convention, at a gathering of journalists in Paris, French aircraft manufacturer Dassault launched its latest jet, the Falcon 5X, a twinjet. The project had been known as the SMS, though Dassault had never officially revealed any details of the program. The 5X, a 69,500-pound large-body bizjet, now occupies a peculiar place in the Falcon lineup. It is a rung below the flagship Falcon 7X, a tri-jet and the first fly-by-wire bizjet. The 7X was launched at the Paris Air Show in 2005 and earned certification in 2007.

But in many ways, the 5X is more airplane than its larger, longer-range and more expensive hangar mate. It has a better cabin, more efficient engines, more advanced avionics and a far more sophisticated digital flight control system.

The program has been ongoing for several years and has been kept under tight wraps. Secrecy has become standard practice with major jet makers when it comes to new programs. Only so much secrecy is possible, however, as the manufacturer needs to work with hundreds of contractors and thousands of workers around the globe to bring a project like this to launch. The result is leaks. We’ve known about this program for a while now, though we didn’t know all the details, and a few that we thought we did know turned out to be wrong.

Today, Dassault is already cutting metal for the first 5X. The company plans to fly the first example in about a year and to earn certification for it by early 2017, an ambitious schedule but one that Dassault has every confidence it can make.

In terms of construction, the 5X is a conventional airplane, by modern standards at least, with largely sheet metal and milled aluminum structures complemented by at least five different kinds of composites, all using highly accurate and automated processes — from fiber placement to resin transfer molding. Composites are used in the nose, horizontal tail and rudder, nacelles, wing roots, and wingtips.

Dassault says the end result of the program will be a fast, modern, wide-body jet with a range of 5,200 nm and one of the best cabins in the bizjet world. It will compete against the Gulfstream G450 and Bombardier Global 5000, two formidable opponents.

Then again, the 5X has the noteworthy advantage of being a newer design than the American and Canadian jets, so Dassault designers had the luxury of including features the competition doesn’t have.

That sounds easy enough, but it’s not. The cabins of both the G450 and G5000 are impressive, large, luxuriously outfitted and light-filled. Moreover, the jets are both highly efficient twin-engine airplanes with impressive ranges, not an easy target for an enhanced legacy Falcon to hit.

So Dassault designers came up with a clean-sheet airplane with nearly every element constituting a revolutionary advancement for the French manufacturer.

Clean-Sheet Approach

It’s hard to know where to start the discussion of the new jet’s innovative features. The new fuselage, with a cabin width of 86 inches, is wider than any Falcon’s and is comparable, if not slightly bigger, in every dimension to the Global 5000 and substantially larger than the G450. With a cabin height of 6 feet 6 inches, it has the tallest cabin in the segment to boot. Complementing the sheer size of the cabin are 28 all new windows, which are the largest on any Falcon, making the cabin one of the brightest passenger seating areas of any bizjet, save the G650.

The 5X has a new-to-Falcon wing, fuselage, flight control system and empennage, which have led many to speculate that the 5X is the first of a new lineup of Falcons — something no one at Dassault is spending much energy trying to deny.

Like the 7X, the 5X is a fly-by-wire airplane, something we expect to become the norm in large bizjet design over time. Based on the technology of the 7X, the 5X’s flight control system is even more advanced. In the 5X, the pilot controls the airplane in a conventional way, using the side-stick, rudder pedals or airbrakes. The flight control computer then applies those commands to the flight control surfaces in a variety of combinations in order to get the very best performance, efficiency and passenger comfort possible.

Up front will be a flight deck that looks similar to that in the 7X, with sidestick controls and an array of large flat panels. Ultimately, Falcon 5X buyers will get the choice of one or two HUDs, which are built by the new supplier Elbit. The enhanced-vision system, also built by Elbit, is mounted in a recessed channel on the upper nose. The new EVS will be better at distinguishing between atmospheric radiance and the runway environment and will be able to see a wider range of light sources, including LEDs. The HUD itself will combine the enhanced vision and computer-generated (synthetic) vision, along with all aircraft primary instrumentation into a very powerful single display.

In back, passengers will have better seating than that of even the best international airline cabins, with a cocoon-like approach that puts everything at arm’s reach, including access to power and Internet, and quick transitions of the seat from business to rest or sleep mode. There are up to six full berths on the 5X. One feature that’s caused a lot of discussion in the bizjet community is the light feature that Dassault calls a “sky light,” which is always presented in quotes, as if to imply it’s not a real window.

The wing of the 5X is a marvel. Unlike Gulfstream’s also marvelous and elegantly efficient wing on the Mach .925 G650, the wing of the Falcon features numerous flight control surfaces with a total of eight flight control devices on each wing: three leading-edge slats, an aileron, a flaperon, two airbrakes and a conventional flap. The trailing edge, like on other Falcons, is beautifully curved, and winglets complete the package aesthetically and functionally. Dassault did all of this while cutting the wing’s weight by 500 pounds, which it partially achieved by using the digital flight control to mitigate high-G events, thereby lowering the G-loading and requiring less structure with equivalent or better safety.

The flaperons are an ingenious multifunction surface that the digital flight control system can make use of like an aileron for roll control, like a flap for increased lift/drag, or as a differential surface to complement the aileron, thereby improving the lift coefficient. The digital flight control system manages all of this in a way a synchronized team of a dozen pilots never could, applying combinations of flaperon with flaps and ailerons, differentially or in concert, to maximize flight performance.

It will also do two things that are unique, to our knowledge, in a fly-by-wire airplane: provide the ability to integrate rudder with nosewheel steering for maximum authority on the ground in gusty conditions and use flaperons in concert with the ailerons to allow a steep approach, such as at London City Airport. In this configuration, the ailerons deflect upward and the flaperons downward to drag and steepen the angle of the nose for better visibility.

New Power

Also new on the 5X are the engines. This is big news and a big departure for Dassault. The Safran Silvercrest engines (also announced for the Cessna Longitude last spring) will enter service as the most efficient engines in their class by a long shot. The engine, with 11,450 pounds of thrust, boasts up to 15 percent better fuel efficiency, Dassault claims. For readers who might have glossed over that, a 15 percent increase in fuel efficiency is a huge improvement. To illustrate this, Dassault calculated the range of the airplane on 10,000 pounds of fuel compared to its main competitors on the same fuel load. Dassault claims the 5X can fly better than 450 nm farther than its main rivals. The result of this and other factors will lead the 5X to be 30 percent less costly to operate than its competitors, which, again, is a big deal.

In addition to being miserly on fuel, the Silvercrest engines will be more than 10 decibels better than Stage 4, the most rigorous noise regulations, while producing 40 to 50 percent fewer emissions than currently allowed under the most stringent emissions standards.

**

Performance**

As everyone knows these days, range is king, and the 5,200 nm range of the 5X is an impressive figure, especially since it will do it on less fuel. That range is for a real trip too, with eight passengers and three crew members flown at Mach .80. Max operating speed for the 5X is .90, so it’s as fast as the 7X, and Dassault expects that shorter flights will be able to be flown at very high speeds, though it hasn’t quoted a figure yet. Landing speeds are as impressively low as the cruise speeds are high, with a typical VREF approach speed of around 105 knots, which is as slow as the best midsize jets. New generation carbon brakes with brake-by-wire, along with the flight control system managing the drag devices and the big thrust reversers on the Silvercrest engines, will help the jet get down and stopped in a hurry.

With the launch of the 5X, Dassault has created an airplane that will have an immediate impact on a growing and increasingly important market segment. We strongly suspect that the airplane, with its great cabin, impressive efficiency and advanced safety features, will inspire new, even larger Falcons down the road.

**

Silvercrest’s Revolutionary Efficiency**

How will this new engine hit its numbers?

When you read that Dassault is expecting the 5X to be 30 percent more cost effective to operate and that its fuel burn will be 15 percent lower than airplanes with existing, comparable engines, you’d be right to wonder if such claims can possibly be true. But there are good reasons to believe they will come to pass.

First, Safran, the company behind Silvercrest, is a $5 billion global engine corporation that builds engines, and a lot of them, for some of the most popular airliners in the world, including the king of them, the Boeing 737. Its credibility is as solid as its R&D is cutting-edge. So we go in assuming the company knows what it’s talking about and it believes the claims will become fact. Moreover, there’s no way that Dassault would put an entire program at risk with an engine that won’t make its numbers.

So how will the Silvercrest do it? The engine, which has a power-to-weight ratio of 5:1, is a low-parts-count, medium-bypass design that uses a five-stage turbine and a four-stage axial compressor to power a 42.5-inch fan blisk (a one-piece unit) that was designed with 3-D modeling processes. A low-parts count, unimaginably tight tolerances and ingenious cooling mechanisms combine to create a really hot combustion section to get every iota possible out of the jet fuel’s potential energy.

After first flights that were scheduled for late 2013, Safran plans to begin production in 2014 for certification in 2015, well ahead of the 5X’s entry into service.

We welcome your comments on flyingmag.com. In order to maintain a respectful environment, we ask that all comments be on-topic, respectful and spam-free. All comments made here are public and may be republished by Flying.