Feature: Revival of American supersonic jet based on new technology

By Peter Mertz

DENVER, the UNITED STATES, Dec. 29 (Xinhua) - Within the next year, California's Mojave desert will see a streak in the sky and hear a sonic boom, as the first commercial supersonic flight in U.S. history hits the Stratosphere.

"The supersonic revival is here," Erin Fisher, Head of Flight Controls for Boom Technologies, told Xinhua in an exclusive interview on Tuesday.

Boom's team of Colorado-based engineers had solid plans to launch a supersonic prototype in 2017, and was scheduled to be in service and full production mode by 2023.

An initial production sequence of 1,300 jets was planned, and reportedly, orders were in for several dozen from American and European air carriers, at a cost of 200 million U.S. dollars each, Boom executives said.

Boom's XB jet would cross the Pacific or Atlantic oceans in less than half the time of current carriers, flying at a speed of nearly 1,500 miles per hour or 2500 kilometers per hour.

Fisher pointed to recent developments in advanced computer technology called Computational Fluid Dynamics (CFD) that makes the "supersonic revival" possible.

"Calculations that would take days or weeks in the 70's now takes minutes," Boom's CFD chief Kenrick Waithe told Xinhua.

Waithe is a key member of the Boom team - a CFD software expert who led Gulfstream's efforts developing quiet boom and supersonic aerodynamics.

Boom's CFD software uses numerical analysis and algorithms to analyze airflows around a vessel at supersonic speeds.

Using a computer, Waithe could run 1,000 simulations a week with tremendous accuracy. The prevalent "wind tunnel" testing of 30 years ago allowed only one or two tests in the same time frame.

Industry analysts say CFD has dropped research, design and development costs by hundreds of millions of dollars.

The time savings is also startling.

"We can cut the overall project time in half," Fisher said. "Instead of taking 10 years to develop a jet of this sophistication, we drop it to five."

Fisher worked on the top-secret, highly advanced Scorpion Jet project at Textron Aviation in Wichita Kansas before joining the Boom team earlier this year.

"For example, the Concorde was one, long tube, and there were no fluctuations," said Fisher. "You won't find too many straight lines on Boom's CFD designed jet."

A 2005 Stanford University study said "improvements in CFD might allow the elimination of a major cycle, and would significantly shorten the overall design process and reduce costs."

The industry jumped on this forecast with fervour. From coast-to-coast, American engineering schools responded with increased CFD programs.

In the west, Arizona State and the University of Colorado (CU) increased CFD classes, and in the east and midwest, Drexel, MIT, George Washington, Georgia Tech, Michigan, and Minnesota, jumped on board.

The recent academic push to increase CFD study occurred in consort with advances in high performance computing, Dr. John A. Evans, assistant professor of Aerospace Engineering at CU-Boulder, told Xinhua.

"Namely, great advances in computing resources, and in particular, parallel computing resources, have enabled engineers to simulate fluid flow about real-scale aircraft, while accounting for complex phenomena such as turbulence," Evans said.

Waithe, who is responsible for advanced computational fluid dynamics methods for all Gulfstream aircraft, agreed with Evans.

"With the advancement of the internet, computing resources no longer need to be kept local," Waithe said. "For a relatively small investment, small companies such as Boom can have the computing resources of NASA."

Evans' CFD classes at CU are filled with young, aggressive engineers who seem to be soaking up the state-of-the-art technology.

"Supersonics are so exciting...it's the wave of the future," said Alex Winoker, 23, an aerospace engineering student who will graduate from CU in 2018.

"Just as my generation is acclimated to the internet and computers, so are we now absorbing this new software," Winoker said. "CFD is triggering huge changes in the aerospace design industry. It's pretty amazing stuff."

According to the Stanford study, "through the systematic use of CFD, a slight design improvement such as a five percent in lift to drag (L/D) ratio change would translate into a similar reduction in fuel consumption."

While CFD design could help fuel consumption, Boom engineers planned to synchronize three smaller GE J85 engines instead of the customary two, which would make fuel consumption a challenge.

Last month, Bjorn Fehrm, an aerospace consultant, released a study of Boom's plan, and cited fuel consumption and per passenger cost as major problems.

So when Boom said flights would cost 2,000 U.S, dollars per passenger - almost half of what current carriers charge for business class customers on trans-Pacific and Atlantic flights - Fehrm contended this was not feasible, due to fuel costs.

However, a recent study by Antony Jameson and Massimiliano Fatica said that with the annual fuel costs of a long-range airliner at 5-10 million U.S. dollars, a 5 percent saving would total a saving of 10 million U.S. dollars over 25 years, or 5 billion U.S. dollars for a fleet of 500 aircraft."

'We're aware of the challenges," Fisher said, who noted the British-French Concorde supersonic jet went bankrupt in 2003, after almost 30 years of service.

"The Concorde was an economic failure with too many seats, it was inefficient with afterburner engines, and was just guzzling fuel," Fisher said.

The new Boom supersonic XB jet was designed to hold 45 passengers instead of Concorde's 100, and to use not only CFD designing, but advanced engines technology, and materials such as carbon-fiber composites, Fisher said.

Fehrm also questioned Boom's 200 million U.S. dollars price tag for the XB jet.

"I'm not sure Boom Technology have reliable estimates of the development costs yet," the former Swedish air force pilot said.

"Until you have found how to (design) your engines, and what that will cost in money and time, you can't really estimate the development costs," Fehrm said.

"Boom for sure has estimates, but looking at the 30 to 50 people they have on the pay list, and in 2023 for certification, I would not give much for their estimates," Fehrm said. Enditem