Status Report Falcon 50EX

Transcription

1 Status Report Falcon 5EX Paul Bowen D Faster, farther and higher Dassault ups the ante in the high-end, mid-size class. By FRED GEORGE assault Aviation just became an even tougher competitor in the upperend business aircraft class. Its Falcon 5 trijet, certified in 1977, currently is unmatched for its blend of cabin volume, maximum range and airport performance. That wasn t good enough for Dassault, especially with the emergence of the speedy Citation X. The firm has decided to replace the Falcon 5, currently the status-quo Caesar of the mid-size class, with a higher performance derivative the Falcon 5EX that will be fitted with more powerful engines and upgraded avionics. Serge Dassault, chairman of Dassault Aviation, announced on April 26 that deliveries of the Falcon 5EX will begin in early Externally, the old 5 and the new 5EX are virtually identical. But, open the cabin door and step up front, and you ll see a world of difference in the cockpit. The Falcon 5EX panel is dominated by four large Collins EFIS tubes, and it is loaded with enough Pro Line 4 equipment, plus other avionics, to make it competitive with the latest generation of longrange business aircraft. (See Collins Pro Line 4 Avionics sidebar.) Unbutton the engine cowls and you can immediately see the reason the new aircraft will fly faster, farther and higher than its predecessor: second-generation, AlliedSignal TFE731-4 turbofan engines. The -4 powerplants, slated for certification in July, have substantially improved high-altitude thrust output, plus better fuel specifics than the -3 engines fitted to the Falcon 5. (See AlliedSignal TFE731-4 Engines sidebar.) Glance at the accompanying TFE731 Thrust vs. Altitude and SFC vs. Altitude performance graphs. The Falcon 5EX s -4 engines have up to 24 percent more thrust and seven percent more fuel-economy effi-

2 COVER STORY FGL & Associates ciency at FL 45 compared to the -3s fitted to the original Falcon 5. Then take a look at the high-speed cruise chart, and notice the change the upgraded engines make in aircraft performance. The Falcon 5EX, carrying eight passengers, will be able to fly 3,25 nm at.8 Mach, with NBAA IFR reserves. The Falcon 5 s range at.8 Mach, carrying the same payload, is closer to 2,625 nm. The reasons? The -4 has more highaltitude thrust, thus allowing the Falcon 5EX to cruise at.8 Mach at a higher altitude. In addition, the -4 has better specific fuel consumption throughout the thrust envelope. Dassault estimates that if you were to fly the 5EX at long-range cruise, the aircraft could travel 2 miles farther than a Falcon 5 at the same altitude, because of its better fuel efficiency. Increased maximum range at.75 indicated Mach number (IMN) is not what most people want, according to Dassault. Operators instead will opt to use the additional thrust to speed up to.8 IMN with no less range than a Falcon 5 flying at.75 Mach, according to Dassault s projections. How about ultimate high-speed dash? The Falcon 5 could sprint from Teterboro to Las Vegas at.83 Mach while flying at FL 35. The -4 engines actually produce as much thrust at FL 39 as the -3 turbofans produce at FL 35. Based on that performance equivalency, B/CA estimates that the Falcon 5EX may be able to cruise at.83 Mach at FL 39, thereby allowing it to take advantage of more favorable winds and, under certain conditions, fly farther than the Falcon 5 at that same speed. Dassault engineers, however, are cautious about making such performance claims before completing comprehensive flight tests. The extra thrust also will enable the Falcon 5EX to climb directly to FL 41 in 23 minutes. The Falcon 5, in contrast, needs 3 minutes to climb to The Falcon 5EX cabin may have double-club seating with a full-width, aft lav. The 16-g seat-strength requirement may rule out the installation of a side-facing divan. FL 39 a performance weak point Dassault candidly admits. MINIMAL WEIGHT GAIN Certainly the upgraded engines and avionics package add weight to the Falcon 5EX, but the increase has been held to a minimum. Dassault estimates that the weight will increase by a scant 45 pounds for aircraft that are comparably equipped in spite of approximately 3 pounds of additional engine weight. (The wiring harness and other interior weight reduction programs save about 18 pounds, and the Pro Line 4 installation saves another 8 pounds.) Dassault claims that the new avion- While the upgraded engines and avionics add weight to the 5EX, the increase has been held to a minimum 45 pounds for comparably equipped aircraft. Dassault Falcon Jet

3 STATUS REPORT Paul Bowen Without a doubt, the Falcon 5EX s substantial performance improvements are a direct result of its three new AlliedSignal TFE731-4 turbofan engines. The -4 has a 4,7- pound sea-level, standard-day thermodynamic thrust rating, enabling it to maintain its 3,7- pound takeoff thrust to 32 C. In contrast, the -3 engine has a 4,5- pound thermodynamic thrust rating that only provides enough temperature margin to maintain 3,7 pounds to 22 C. Features of the -4 include a fullauthority, single-channel, N1 (fan speed)-referenced digital electronic engine control (FADEC), with a hydromechanical back-up; a singlepiece sun gear for greater durability; helical versus straight-cut gears for lower noise and vibration; and several ease-of-maintenance design benefits, such as individually replaceable fuel nozzles. The Falcon 5 already has excellent airport performance, so there is no need to bump up the Falcon 5EX s takeoff thrust rating beyond 3,7 pounds per engine. However, the -4 produces almost one-fourth more thrust at high-cruise altitudes than does the -3. At 4, feet, the engine (uninstalled) actually produces 96 percent as much thrust as the -5BR turbofan on the Falcon 9B. Just as importantly, the -4 engine squeezes seven percent more energy out of each pound of fuel than does the -3 turbofan on the Falcon 5. It even has better fuel efficiency than the -5BR the most fuel-miserly version of the ALLIEDSIGNAL TFE731-4 ENGINES first-generation TFE731 engines. The -4 s 2.9:1 bypass ratio is slightly higher than the -3 s 2.68:1 bypass ratio, but most of the SFC improvement is due to its 22:1 overall all-pressure ratio a 2-plus percent improvement. Pressure ratio improvement is the result of both better internal aerodynamics, such as a highpressure compressor with 35 percent more com- pression, and im- 2,5 proved manufacturing processes, resulting in tighter tolerances and, thus, less leakage. AlliedSignal claims that the internal design changes, including upgraded hot-section materials and a machined combustor, will reduce the variability woes that plagued the -3. Physically, the -4 has a slightly larger fan diameter than the -3, but its front flange is the same size, allowing it to use virtually the same inlet duct. The -4 basically is the same size as the -3 overall, Net Thrust (lbs) SFC (lbs/lbm/hr) 2, 1,5 1, thereby raising, in our opinion, the probability of a future retrofit program. Admittedly, each -4 and its nacelles weighs 1 pounds more than the -3, but the additional weight is partially offset by better fuel specifics. The more-robust -4 also will have a lower cost of operation than the -3. The fan, compressor and turbine disks (not including the blades) all have 1,-cycle design lives. The engine will have an initial major periodic inspection (MPI) interval of 2,5 hours and a 5,- hour compressor zone inspection (CZI) interval. The MPI will be stretched to hours, and CZI will be lengthened to 6, hours after the engine reaches maturity. Changes such as these help reduce the hourly maintenance service plan rate of the -4 to $11.4 from $18.94 for the older -3 engine. THRUST vs. ALTITUDE Falcon 5EX Falcon 5 TFE731-4 TFE731-3 Conditions: Maximum climb thrust; standard day 1, 2, 3, 4, 5, Altitude (ft) SFC vs. ALTITUDE Conditions: Maximum climb thrust; standard day TFE731-3 TFE Falcon 5EX.66 Falcon , 2, 3, 4, 5, Altitude (ft) Source: AlliedSignal Engines Source: AlliedSignal Engines

4 Dassault Falcon Jet COLLINS PRO LINE 4 AVIONICS At 15,52 pounds, the Falcon 5EX s fuel capacity remains unchanged... Upon first glance, the cockpit of the Falcon 5EX easily could be mistaken for that of a Falcon 2. The newest Falcon trijet, similar to the Falcon 2, has a Rockwell Collins Pro Line 4 avionics suite with four 7.25-inchsquare EFIS CRTs that dominate the instrument panel. Above the instrument panel is a newly designed glareshield control panel that houses display and flight-guidance system controls, including lateral and vertical navigation functions. The Pro Line 4 system uses the Collins-pioneered hub-and-spoke architecture, with the integrated avionics processing system (IAPS) box forming the hub. The IAPS contains a single-channel, digital autopilot controller, dual flightdirector computers, data concentrators and an integrated maintenance diagnostics computer all monitored by control-display units in the center console. Dual Pro Line II radio systems, featuring ARINC 429 tuning and data interfaces, are controlled by 4-series radio tuning units that also are located in the center console. In addition, the suite includes a Collins ALT 55B radio altimeter, TWR-85 Doppler turbulence detection weather radar and dual, digital air-data computers. Honeywell will supply the dual Laseref III inertial reference systems, w h i l e AlliedSignal has been tapped for the dual Global GNS-XES FMSes, with integral GPS sensors, and will supply a 15-watt KHF-95 HF transceiver. Sextant s engine instrument displays (EIDs) and standby airdata instruments will be in the panel, flanked by a J.E.T. AI-85 standby attitude indicator (peanut gyro). A Universal Avionics Systems cockpit voice recorder rounds out the package. Options include Collins AHRS in place of the Laseref III IRS, Collins TCAS-94, AlliedSignal Mk-V GPWS, AlliedSignal Flitefone 8 or the Magnavox MagnaStar air-toground radiotelephone. If customers so request, other FMSes may be offered as options to the GNS-XES. Dassault also is considering offering a satellite communications package and a complete suite of airborne office equipment as options. The Falcon 5EX avionics package actually is being installed on Falcon 5 serial number 252, with Dassault Falcon Jet and Collins jointly intending to obtain an STC. Dassault Falcon Jet s Little Rock, Arkansas facility, along with a select number of other service centers, will be authorized to install the Falcon 5EX s Collins Pro Line 4 avionics package on existing Falcon 5 aircraft. ics package has less and lower weight wiring, plus a lighter interior than the Falcon 5. The changes will reduce the empty weight by 24 pounds, thus helping to offset the extra 3 pounds of the new engines. However, the 45-pound estimated weight increase should be put into the context of the FAA s 1993 most current FAR Part passenger seat strength requirements the so-called 16-g seat rule for all new interior completions. In our opinion, the highstrength seat rule may add a few pounds to the 45-pound estimated increase. The 16-g seat requirement also may rule out the three-place, side-facing divan as shown in our interior photos. The side-facing divan could be installed if Dassault obtains an FAA waiver. At 15,52 pounds, the Falcon 5EX s fuel capacity remains unchanged, but its MTOW will increase to 39,7 pounds from 38,8 pounds for the Falcon 5, thereby allowing it to carry a 2,4-pound payload with maximum fuel an increase of almost 44 percent compared to its predecessor. Notably, the increase in MTOW isn t much of a stretch much less a strain on the Falcon 5EX. Dassault has offered an optional 4,78-pound MTOW package for the Falcon 5 for several years. ISA AIRPORT PERFORMANCE UNCHANGED? Recertifying all the standard-day airport performance numbers, particularly takeoff field length and one-engine inoperative (OEI) climb performance, would have added months to the certification process and plenty to the purchase price. Dassault believes the current Falcon 5 s airport performance numbers represent one of the aircraft s strong

5 STATUS REPORT Only light business jets will best the Falcon 5EX in airport performance, and few of them can beat its takeoff and landing reference V-speeds. BFL (ft) BALANCED FIELD LENGTH vs. RANGE AT.75 MACH 7, 6, 5, 4, Conditions: 8 passengers; NBAA IFR Reserves 1, 2, 5, ft; ISA+15 C 5, ft; ISA +15 C BFL (ft) BALANCED FIELD LENGTH vs. RANGE AT.8 MACH 7, 5, ft; ISA+15 C Conditions: 6, 8 passengers; NBAA 5, ft; ISA IFR Reserves 5, +15 C 4, 1, 2, suits, so for now the firm has elected to flat-rate the takeoff thrust of the -4 engines to 3,7 pounds the same as the -3 engines. The -4, though, has a sea-level, standard-day, maximum thermodynamic thrust rating of 4,7 pounds, versus 4,5 pounds for the -3, resulting in a wide temperature reserve for hot-and-high departures. With the additional 9 pounds of MTOW, the Falcon 5EX s standardday, weight-to-thrust ratio increases to 3.58 from 3.5 for the Falcon 5. As a result, we anticipate that the Falcon 5EX will need more runway than the Falcon 5 when departing at MTOW. However, the -4 s much-improved hot-and-high thrust output will improve its high-density altitude airport performance numbers, in spite of the gain in MTOW. We estimate that the Falcon 5EX at its MTOW of 39,7 pounds, for example, will need less runway when departing some hotand-high airports than the Falcon 5 requires at its 38,8-pound MTOW. The Falcon 5EX s performance advantage at very-hot-and-high airports is indeed impressive. Departing Mexico City s Toluca Airport (elevation 8,848 feet) on a 33 C day, the Falcon 5EX will be able to fly eight passengers 2,719 nm at long-range cruise, with NBAA IFR reserves. If needed, that would be enough range to reach Halifax, Nova Scotia or Lima, Peru. Also, the -4 engine s increased climb thrust will sizably shrink the time needed to reach top-of-climb. Passengers will reap a noticeable benefit. After departing from Toluca, for instance, the Falcon 5EX will spend less time in summer turbulence prior to reaching its initial cruise altitude. PRICE VERSUS PERFORMANCE Dassault, continuing its goal of reducing the price escalation of its business aircraft, will price the Falcon 5EX about $1,, higher than the current Falcon 5, resulting in a B/CA equipped price of $15.7 million. Only light business jets will best the Falcon 5EX in airport performance, and few of them can beat its takeoff and landing reference V-speeds. With 7 cubic feet of cabin volume, only large cabin business aircraft will offer passengers more room. The Falcon 5EX still will finish second in any sprint against Cessna s.92-mach Citation X, but longer races, such as New York to Los Angeles against strong headwinds, may even the race odds. Yet the Falcon 5EX s threeengine configuration and improvedperformance -4 Payload (lbs) 4, 2, 1, turbofans should give it an edge when departing from hot-and-high airports compared to most twin-engine competitors. Its increased MTOW, which is now quite useful even on hot-andhigh days, noticeably will stretch its seats-full range. Few aircraft will be able to top the Falcon 5EX for avionics power. The Collins Pro Line 4 package, including large-format displays, gives pilots the next-generation features and capabilities they expect on contemporary -plus-mile-range business aircraft. Ultimately, speed is what will sell the Falcon 5EX. Few competitively priced aircraft will be able to match its 459 KTAS high-speed cruise or its point-to-point block times. Many business aircraft operators just won t wait any longer. B/CA NBAA IFR PROFILE ISA.75 Mach.8 Mach 8 Passengers 1, 2, Note: With 8 passengers and NBAA IFR reserves 3,25 nm at.8 Mach, FL 39/43; 3,265 nm at.75 Mach, FL 41/45