Supersonic bizjet designers troll for manufacturing partners
If paper was aluminum, glass and titanium instead of just paper, two Nevada-based groups developing supersonic business jet designs would have revolutionary aircraft ready to fly. To date, though, the specifications publicized by Aerion in Reno (Booth No. 1154) and Supersonic Aerospace International (SAI), with offices in Las Vegas, are little more than exciting numbers stemming from what the promoters call promising preliminary research and development. Neither is known to have actually cut metal for a flying prototype.
Aerion maintains its Supersonic Business Jet (SSBJ) program is on track for certification in 2015 and is backed by letters of intent. “Aerion continues to maintain a letter of intent backlog of about 50 aircraft,” a spokesperson said. “Only two deposits have been refunded since the beginning of the financial crisis.”
SAI, for its part, publicizes an arrangement for Lockheed Martin’s Skunk Works to design its Quiet Supersonic Transport (QSST). The company projects first flight in 2014 and certification in 2016.
Both Aerion and SAI say their schedules are contingent upon gaining airframe OEM partners to build the aircraft.
An Aerion spokesman said discussions with OEMs are “progressing.” No one from SAI was available for comment.
SAI’s QSST design envisions a business jet with a Mach 1.8 max cruise speed operating at FL 470. It would be capable of balanced-field length runway operation under 7,500 feet. Aerion’s SSBJ would cruise at Mach 1.6 with a maximum altitude of FL 510 and be able to operate with a balanced field length of less than 6,000 feet. Similarities between the two include supersonic range greater than 4,000 nm, configurations for up to 12 people and a base price of approximately $80 million in 2009 dollars.
Both companies claim their designs will reduce supersonic shock wave impact at the surface to a fraction of what the Concorde produced. SAI’s design is based on a delta wing with an inverted V-tail. Specifications for both designs show similar external dimensions, but the Aerion SSBJ mtow is listed as 90,000 pounds while that of the SAI QSST is 153,000 pounds, approximately the weight of a Boeing Business Jet. Each design incorporates a “stand-up cabin” (just over six feet high).
Aerion describes its product as an airframe with a straight wing featuring “natural laminar flow (NLF) aerodynamically optimized for transonic and supersonic flight up to Mach 1.6 with boom-less flight at Mach 1.1.” It calls the delta wing “the shape that defined performance in the 20th century” and its NLF wing “the shape of the emerging supersonic market in the 21st century.”
Aerion has scheduled flight tests of a larger NLF wing section aboard a NASA F-15B Eagle strike fighter to define manufacturing tolerances for optimum laminar flow over a supersonic airfoil. The company said flights are “on track, most likely in November, depending on NASA scheduling” at the Dryden Flight Research Center on Edwards Air Force Base in California. With the ability to carry a larger wing test section aloft, Aerion said it can investigate the effects of various surface imperfections. The wing on the full-scale Aerion aircraft will be thin, tapering from about nine inches in thickness at the root to three inches at the tip. Manufacturing tolerances will need to be carefully defined to ensure laminar flow, which is what these tests will help to determine. The new wing section will investigate higher Reynolds number conditions, closer to the actual flight conditions of a full-scale wing at altitude.
Both Aerion and SAI claim to be the only developers with supersonic designs to use “systems and materials [that] are conventional, reliable and commonly in use in current production design” as well as “conventional materials and manufacturing techniques…” Aerion says its SSBJ will not contain “exotic structural materials or manufacturing techniques. Systems will represent best current practices and be similar to those now used for large business jets.”
Aerion further stated, “A suitable engine [the Pratt & Whitney JT8D-219] is available and in widespread current use.” SAI said it has been discussing “concept engine” designs with Pratt & Whitney, Rolls-Royce and General Electric, and expects to select an engine supplier next year.
Meanwhile, Aerion and NASA have tentative plans for testing transonic and supersonic laminar-flow wing performance to establish surface quality requirements at NASA’s Ames Research Center wind tunnel complex in Sunnyvale, Calif. Aerion’s Web site listed September 2009 as the testing start date. However, the company said discussions with NASA regarding checks to assess the Ames Center wind tunnel’s suitability “are ongoing,” and a “schedule has not been set” for the collaborative effort.
Aerion had planned to test a selection of 7-percent scale exhaust nozzles in a United Technologies noise-measurement wind tunnel this month and, concurrently, engine inlet designs. However, in late August it reported, “The test article model nozzle design has been completed and we are awaiting the opportunity to conduct these tests in conjunction with an OEM partner, so the timing is dependent on the establishment of a partnership arrangement.” Aerion previously modeled numerous nozzle configurations in computer simulations and tested them as small-scale models in an anechoic chamber at the University of California, Irvine.