Two companies reveal supersonic bizjet plans

 - December 14, 2007, 6:48 AM

The void in the aeronautical spectrum created by the retirement of the Anglo-French Concorde fleet in October last year stands to be filled by two supersonic business jet (SSBJ) programs that were unveiled at last month’s NBAA Convention. Two start-up companies showed competing 12-passenger, 4,000-nm-plus SSBJ designs, dismissing assumptions by established business aircraft manufacturers that such a machine is not yet feasible economically or environmentally.

“Concorde may have been relegated to museums, but the world has not slowed down. Indeed, the reverse is true; major corporations and governments have a clear need for faster travel,” noted Aerion vice chairman and business aviation veteran Brian Barents.

Reno, Nev.-based Aerion on the eve of the NBAA show took the wraps off a design for a Mach 1.6 twinjet that it said could enter service by 2011. The following day, Las Vegas-based Supersonic Aerospace International (SAI)–headed by Michael Paulson, son of Gulfstream mogul Allen Paulson–announced a Mach 1.8 twinjet that could be certified as early as 2012. Both companies estimate that their respective aircraft will retail for about $80 million apiece.

While the price of the two aircraft is the same, the underlying philosophies behind the aircraft designs couldn’t differ more. The Aerion SSBJ, which will combine a patented natural laminar flow (NLF) wing platform with certified airliner powerplants (the Pratt & Whitney JT8D-219, as found on the McDonnell Douglas [Boeing] MD-80 series), is claimed to fly efficiently at either subsonic or supersonic speeds, meaning the company’s business case doesn’t hinge on whether FAR 91.817, which prohibits supersonic overland flight, can be changed. But if the FAR is ever relaxed, Aerion said its SSBJ could achieve boomless cruise at Mach 1.1. Barents explained this approach as “taking the path of least resistance.”

On the other hand, SAI’s jet– dubbed the Quiet Small Supersonic Transport (QSST)–will employ both yet-to-be-certified engines and patented low-sonic-boom technologies. However, since the SAI jet will incur a 10-percent performance penalty in subsonic flight and because of the significant focus on incorporating low-boom technologies into the aircraft, the company is relying on regulatory changes that will allow “quiet” supersonic flight over land.

While both projects involve risk, the projected development costs reveal just how much risk each company is taking: Aerion said the price tag for bringing its SSBJ to market will be between $1.2 billion and $1.5 billion; SAI is talking of between $2.5 billion and $3 billion for its QSST. Both companies plan to be part of consortia that will bring risk-sharing partners and other suppliers under their wings.

The Aerion management team is filled with heavy-hitters. Joining Barents is chairman Robert Muse Bass; director and chief technology officer Dr. Richard Tracy; and director and COO Michael Henderson.

Barents is widely known in business aviation circles for his roles as president, CEO and managing partner of Galaxy Aerospace (1996 to 2001); president and CEO of Learjet (1989 to 1996); a senior vice president for Cessna Aircraft; and a past vice chairman of the General Aviation Manufacturers Association. He also sits on the boards of Nordam, Kaman, Eclipse and Embry-Riddle Aeronautical University.

Leading the start-up company’s venture group funding development is Bass, the billionaire president of Keystone and founder of the Oak Hill partnership, which holds $10 billion in investments. The Fort Worth, Texas native holds a bachelor’s degree from Yale University and an MBA from the Stanford Graduate School of Business.

Tracy is an aerodynamicist who formed the Asset Group (Affordable Supersonic Executive Transport) in 1991 to pursue research into the commercial application of NLF technology, leading to the present wing concept that he patented in 1994. He also brings business aviation experience–as chief engineer for Bill Lear’s LearAvia in the 1970s, Tracy led the advanced design of the Learstar 600, which became the Challenger 600. He initiated the design of the composite Lear Fan and led the development effort on that aircraft through its successful first flight. Tracy holds bachelor’s, master’s and doctorate degrees, the last in hypersonic aerodynamics, from Caltech. He is also a licensed pilot and has logged more than 1,500 hours.

Rounding out the executive team is Henderson, who most recently led Boeing’s advanced design and manufacturing technologies team. From 1987 to 1995 he served as the airliner manufacturer’s program manager for high-speed civil transport. He also headed Boeing’s high-lift research unit, which developed advanced computational tools for high-lift systems design.

An engineering group in Palo Alto, Calif.–led by Stanford aerodynamics professor Dr. Ilan Kroo–supplements Aerion’s engineering and management team. This West Coast group, which specializes in advanced computational methods for flow analysis, has assisted in the optimization of the Aerion SSBJ airframe design.

Two-year-old Aerion claimed it is engaged in advanced development and that it has recently completed the initial design cycle. To date, this has included in-flight testing of a supersonic NLF wing section on a NASA F-15 testbed in 2000; computational fluid dynamics (CFD) analysis of the airframe; finite element analysis; engine/airframe integration studies; and initial systems design. By next summer the company will have completed a second design cycle that includes high- and low-speed wind tunnel tests, as well as continued optimization and CFD analyses. After this research, Aerion would decide whether or not to launch the program and proceed with construction of a prototype for flight test.

NLF Technology
Key to the Aerion SSBJ design is the supersonic NLF technology, which is said to substantially reduce drag at supersonic and high-subsonic cruise speeds. This efficiency allows the Aerion design to employ existing airliner powerplants, circumventing the dilemma of previously proposed, and eventually shelved, SSBJs. (Beyond providing the JT8D engines, Pratt & Whitney is also a partner in the design phase of the Aerion SSBJ program.)

Engine and nacelle integration will allow the aircraft to meet or exceed Stage 4 noise requirements, Aerion predicts. Peter Robinson, P&W’s program manager for advanced commercial engines and technology, told AIN that the SSBJ’s engine-inlet design will decelerate the airflow entering the JT8Ds to subsonic speed. However, reducing this flow speed also increases the temperature of the air entering the engine, which in turn puts additional stress on the powerplants. Regardless, P&W expects an engine TBO of at least 2,000 hours.

Aerion will make the airplane’s wings from carbon-fiber composites to provide the required ratio of stiffness to weight, employing construction methods common on modern fighters. Since the airplane’s top speed of Mach 1.6 eliminates the requirement for special high-temperature materials and complex systems, Aerion has opted for a conventional aluminum fuselage. However, the wing leading edges will be milled from a single piece of titanium to allow for an electrical anti-ice system. The leading-edge extensions near the fuselage will have a bleed-air anti-ice system, Henderson added.

Aerion said the airplane will be fuel-efficient at cruise speeds just below the speed of sound, allowing it to perform short- and long-haul overland missions with the same economies as today’s large business jets. According to the company, operating costs (direct and fixed combined) are estimated at $6.80 per nautical mile at supersonic speeds, and $8 per nautical mile at subsonic speeds. This compares with per-nautical-mile operating costs of about $7.90 for the Gulfstream 550 and $8.50 for the Bombardier Global Express, according to Aerion.

Range is roughly the same at both subsonic and supersonic speeds and will exceed 4,000 nm. Early estimates peg the range at approximately 4,800 nm at Mach 0.95 and close to 4,600 nm at Mach 1.5.

With the Aerion SSBJ, a New York-to-Paris flight could be completed in 4 hours 15 minutes, versus about 7.5 hours in a subsonic business jet. If FAR 91.817 prevails unchanged, and overland supersonic flight remains prohibited, the SSBJ could fly from Teterboro, N.J., to Los Angeles at speeds up to Mach 0.99 in less than four hours.

Thanks to the SSBJ’s straight wing and full-span flaps, Aerion said the twinjet will have an approach speed of 125 knots, allowing the airplane to operate from airports with 6,000-foot runways. The aircraft’s ceiling will be 51,000 feet, so as not to complicate certification efforts under FAR Part 25.

Over the next 18 months or so, the company will engage in discussions with major airframe manufacturers and first-tier suppliers to establish risk-sharing partnerships to conduct detailed design, testing and certification of the 90,000-pound-mtow airplane. Aerion projects a five-year development program with two ground-test articles and three flight-test aircraft. Assuming a full go-ahead, first flight is scheduled for 2008 or 2009, with certification following in 2010 or 2011.

Since Aerion has merely unveiled, not launched, the SSBJ, the company is not yet taking orders. However, Barents said there is considerable interest from the fractional providers. He specifically named NetJets, whose executive vice president, Richard Smith, sits on Aerion’s five-member product review board. Barents expects the fractionals to account for up to half of all Aerion SSBJ sales, and he added that the government, military and head-of-state markets could also account for a sizeable percentage of sales.

And since Tracy said the design is “scalable,” Aerion could eventually develop a “small transport-capability” supersonic airplane. But for now, Aerion will continue to focus on being the first to bring an SSBJ to market, Barents said.

Quiet Small Supersonic Transport
SAI said its low-boom SSBJ, also to be constructed of “nonexotic materials,” would carry eight to 12 passengers at altitudes up to FL600. Under current plans, the 153,000-pound-mtow airplane would first fly in 2010 or 2011 and gain certification in 2012.

Paulson explained why he is pursuing an SSBJ: “Before my dad passed away [in July 2000], we had many conversations about building a supersonic business jet. He thought supersonic transport was the future. In the last conversation I had with him before he died, he asked me to continue his SSBJ dream.” His father left behind a trust fund to carry on his dream, and SAI is a means to turn that vision into reality.

In the late 1990s, the elder Paulson contacted Lockheed Martin to work on a low-boom SSBJ, and after several meetings the two formed a business relationship. In 2001 the younger Paulson solidified the relationship by forming SAI and awarding a multimillion-dollar contract to Lockheed Martin Skunk Works to design the airplane. Since Lockheed Martin is not fluent in business aviation, Paulson tapped Clay Lacy Aviation president Clay Lacy as a consultant to the program. (Lacy was also a long-time friend of the elder Paulson.)

What emerged some three years and $25 million later was the QSST design. According to SAI, the QSST integrates state-of-the-art technologies–such as aerodynamic shaping and a patented inverted V tail–to achieve “unprecedented levels of sonic-boom suppression” to facilitate both transcontinental and international supersonic flight. However, the design will be statically unstable in pitch, requiring the use of a fly-by-wire flight-control system. The QSST will need to use 8,000-foot runways, and SAI said initial studies have shown that customers will accept this limitation.

Since the advanced integrated design features reduce the sonic boom level to an overpressure of 0.3 psi–less than one one-hundredth that of Concorde–Paulson contends that SAI operators will be able to secure permission to fly at supersonic speeds over land. And even if the FAA won’t amend FAR 91.817 to allow supersonic travel over the U.S., he said the project will continue since “authorities might later change their position.” But Paulson conceded that the QSST will have a 10-percent range penalty if forced to fly at subsonic speeds over land.

SAI indicated that the QSST project will involve an “international consortium” of risk-sharing partners–and there appears to be considerable risk to be shared with those potential partners. The first gamble is the fact that the patented QSST technologies have been tested only on computer screens and in wind tunnels.

During Phase 2 of the project, which will begin in January, SAI will consider building a 60- to 70-percent-scale demonstrator to prove the design’s low-boom technologies. Paulson said this could add “tens of millions of dollars” to the cost of the program, quite apart from the time penalty.

Adding another dimension of risk is the QSST’s engine. Unlike the engines that will power the Aerion SSBJ, the two 33,000- to 35,000-pound-thrust engines that the QSST would require have yet to be designed and built, let alone tested and certified. General Electric, Pratt & Whitney and Rolls-Royce have provided competing engine concepts– all without afterburners–for the QSST. All of the engine offerings will be based on existing cores, but with tailored inlet, fan and nozzle systems, according to SAI.

While SAI said the three powerplant contenders would be highly efficient and meet Stage 4 requirements, the company couldn’t say when any of them would be certified. Engine selection is expected sometime next year.

Another hurdle is the regulatory issue. If SAI can’t convince the FAA to change its position on overland supersonic flight, then use of the aircraft will be limited largely to over-water use, given the performance penalties of flying subsonic in the QSST. This could reduce customer interest.

Following Phase 2, which will end in mid-2006 or early 2007, SAI plans to go directly into development and production. SAI said Phase 3 will focus on design and Phase 4 is manufacturing. The start-up company plans to build three flight-test aircraft on production tooling.

Like the Aerion SSBJ, the QSST is scalable, and SAI and Lockheed Martin envision a stretched version with 30 business-class seats.