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Williams International and Rolls• Royce are jointly developing a 1,900• pound-thrust engine-the FJ44.

superseded by turbofan (fanjet) engines, horsepower Textron Lycoming 10-540 1991, and certification is expected in Oc• are the domain of corporate aviation be• piston engine (excluding the propeller). tober 1992. The CitationJet, like other cause jet engines are prohibitively ex• Rolls-Royce is sharing in the engi• aircraft of the same genre, probably will pensive and have an insatiable thirst for neering of the engine and will be manu• be certified for single-pilot operation. fuel. But it will not be like this for long. facturing the turbine rotors and low• Another aircraft incorporating the di• Williams International and Rolls• speed turbine shaft. The Williams-Rolls minutive Williams-Rolls turbofan en• Royce are jointly developing a 1,900• partnership assures that support for the gines is the Swearingen 5]30, which is pound-thrust turbofan engine. The com• FJ44 will be available through Rolls• described as a miniature Boeing because pact Williams-Rolls FJ44 is the key to a Royce's worldwide facilities. Williams the wings have 30 degrees of sweepback new genre of entry-level business jets will be manufacturing all other parts and and less area (165 square feet) than a that will operate not only faster, but assembling the engine in Ogden, Utah. Cessna 172's. (The smallest Learjet has a more efficiently than turboprop aircraft. Certification is expected in early 1992. wing area of 234 square feet.) This will Williams International has developed Three aircraft currently are being devel• enable the 5]30 to have a maximum 30 different types of small turbine en• oped to take advantage of the compact cruise speed of Mach 0.77 and a redline gines and has manufactured 9,000 of Williams-Rolls turbofan. (Mmo) of Mach 0.82. them for U.S. cruise missiles and a vari• One is the Cessna CitationJet Model Like a Boeing, the wing features exotic ety of other military uses. The FJ44, 525, which is intended to succeed the high-lift devices: full-span, leading-edge however, is a new design under devel• original Citation 500 and its replace• slats and genuine Fowler flaps. These opment since 1983, according to Wil• ment, the Citation 1. The new Cessna reduce stall speed to just 80 knots. liams' president and founder, Dr. Sam reportedly features the first supercritical The S]30's designer, Ed Swearingen, Williams. It is not a modified cruise-mis• airfoil on any to achieve says that the aircraft will be pressurized sile engine, as has been reported. laminar flow. with a lO-psi differential, which is more The FJ44 represents a design break• The Model 525 will have a six-place than that of a Boeing. This means that a through. "This engine will have very cabin and is designed to operate from sea-level cabin can be maintained to low operating and maintenance costs. 3,000-foot runways. With a maximum 28,000 feet; at its maximum operating One reason is that it has only seven hun• cruising speed of 380 knots and a gross altitude of 42,000 feet, the S]30's cabin dred parts compared to larger engines, weight of 10,000 pounds, the CitationJet altitude will be only 4,200 feet. which have fifteen to twenty thousand is faster, more efficient, and weighs al• Swearingen anticipates that the $2.6• parts." It is noteworthy that the dry most a ton less than the Citation 1. million SJ30 will make its maiden flight weight of an FJ44 is 445 pounds, which Cessna reports that the first flight of by the end of June. Certification is ex• is less than the dry weight of a 250- the prototype is scheduled for May pected 30 months later.

46. JUNE 1990 The only flying example of an aircraft piston or turboprop engines to be carry eight (including pilots) in a high• powered by the Williams-Rolls FJ44 tur• mounted on the wings. This explains the density seating configuration. bofan engine is ' Tri• purpose of the ventral fin: It is provided Unless you know what to expect, a umph Model 143, which was designed to prevent propeller damage in case of takeoff in the Triumph is startling. I had by of Voyager fame. Scaled excessive takeoff rotation or landing just advanced the thrust levers when it Composites designs and builds proof• flare. This is why the aircraft has such was time to rotate (88 knots) and lift off of-concept aircraft. The company is hop• long legs and sits so high, which gives it (98 knots). But then, how many jets use ing to sell the rights to the Triumph de• a uniquely handsome appearance. less than 1,500 feet of runway? sign to a manufacturer that will certify The cabin has the same dimensions as Subsequent climb performance is also and produce it. a Cessna 414's and presumably can swift: 4,500 feet per minute at 5,000 feet The Triumph's airframe consists of msl, 3,000 fpm at 15,000 feet, and 1,750 composite materials, carbon fiber where fpm at 25,000 feet. (Uke piston engines stiffness is critical and fiberglass else• without turbochargers, jet engines are where. Rutan claims that it has only 10 normally aspirated and lose power with percent of the parts that the airframe altitude. That's why the climb rate of jet would have if it were constructed of con• aircraft also decreases with altitude.) ventional materials. The aircraft can take off at its maximum• Another Rutan trademark is the ca• allowable gross weight of 9,000 pounds nard, which gives the aircraft three types and climb uninterrupted to 41,000 feet. of lifting surfaces (including the wings The Triumph's handling qualities are and horizontal stabilizer). The wings conventional and predictable except that' and canard each incorporate single-slot• roll control requires a somewhat heavy ted flaps. The Model 143 appears to hand on the control wheel, and the elec• tric pitch trim operates much too slowly. have a pair of rudders, but the lower The Triumph is equipped with speed brakes control surface is an electrically operated and thrust "attenuators," but thrust reversers Also, the aircraft tends to roll during ac• trim tab. were deemed unnecessary because of the celerated, flaps-up stalls. It is otherwise The design of the Triumph also allows airplane's short landing rollout capability. stable, responsive, and a joy to fly (even

48. JUNE 1990 during engine-out stalls). sive specific range of 0.7 nm/lb. The only difficulty I had with the air• Most existing business By way of comparison, most turbo• craft was losing altitude; it does not jets obviously are prop aircraft are much slower and typi• come down easily. I had to slip the Tri• cally cannot travel more than 0.65 nml umph to prevent drifting above the faster but typically lb. The outstanding exception is the glideslope while approaching the run• Piaggio Avanti, which comes closest to way at 100 knots with the engines idling can claim only half matching the Triumph's efficiency I and the gear and flaps extended. This is the fuel efficiency speed combination. Most existing busi• the result of a combination of aerody• ness jets obviously are faster but typi• namic cleanliness and approximately of Rutan's fuel miser. cally can claim only half the fuel effi• 100 pounds of idle thrust from each en• ciency of Rutan's fuel miser. When gine. The aircraft has thrust attenuators (such as Pratt & Whitney ) be• operating at long-range cruise at their that can be deployed to block half the cause these would make the aircraft too most efficient altitudes, the Cessna Cita• tailpipe area and eliminate most of the tail heavy. Also, the additional power tion II and the Learjet 31, for example, idle thrust. Speed brakes are available to that such engines provide would be can fly only 0.47 and 0.51 nm/lb, re• help in the descent. The aircraft does not wasted because each engine inlet ingests spectively. have thrust reversers because, with a air from above the upper surface of each The turboprop airplane has been suc• landing roll of less than 2,500 feet, they wing. Too powerful an engine would ac• cessfullargely because it is less expen• are not needed. celerate the local velocity of air flowing sive than a business jet to purchase and The seeds for the Triumph were over the wing so much that it would operate. But with the arrival of entry• planted in October 1984 when Scaled become transonic-it would approach level turbofan aircraft that are faster and Composites began to develop a cabin• the speed of sound. This would create more efficient, one must question the fu• class twin to compete with Cessna's an unacceptable increase in drag due to ture of turboprop aircraft. 400-series aircraft. Such a design, Rutan the formation of shock waves along the Perhaps of greater importance to most was advised, also should be capable of upper surfaces of the wings. The Wil• AOPA Pilot readers is whether the evo• incorporating turboprop engines. As the liams turbofans, therefore, are a good lution of the compact FJ44 turbofan new aircraft began to take shape, Rutan match for the airplane. points toward the development of even recognized that it "was also just the right The combination also is extremely ef• smaller, more efficient engines for use in weight and size to accommodate Dr. ficient. When the Triumph operates in a wider variety of general aviation air• Williams's new turbofan." So Rutan op• long-range cruise at its maximum op• craft. Experts are unwilling to go on timized the design to use the FJ44 en• erating altitude of 41,000 feet, it has a record with a prediction, but they con• gines, even though this could result in a true airspeed of 295 knots and covers 0.9 cede that turbine power for light aircraft slightly less efficient aircraft if piston or nautical miles for each pound of fuel is becoming less of a dream and more of turboprop engines were used. consumed. Using maximum cruise a possibility. In the meantime, the Wil• The Rutan Triumph cannot accom• thrust (still at 41,000 feet), it zips along liams-Rolls FJ44 is a giant step in the modate significantly larger jet engines at 375 knots while boasting an impres- right direction. Our direction. 0

50. JUNE 1990