FROM the doodlings of daVinci and the penned fantasies of Jules Verne to the tangible accomplishments of the Wright brothers and other aviation pioneers, mechanized flight has captured the imagination of humanity through the centuries. Even today, with atmospheric and space flight a reality, there are still aviatory realms to dream about and conquer. Hypersonic flight at speeds 5 to 12 times the speed of sound (Mach 5 to Mach 12) is one such area of interest to the commercial and defense communities.|
At Lawrence Livermore National Laboratory, aerospace engineer Preston Carter has invented a concept for a next-generation hypersonic aircraft, dubbed HyperSoar, that could fly efficiently, economically, and cleanly.
Flying at Mach 10 (3 kilometers per second), HyperSoar could reach any point on the globe within two hours. (The fastest military plane, the SR-71, flies between Mach 3 and Mach 4, while the commercial Concorde only reaches Mach 2.) HyperSoar would also have twice the fuel efficiency of commercial airliners, be three to five times more efficient in putting satellites in space than today's launch systems, and use liquid hydrogen fuel, which produces simple water vapor when burned.
HyperSoar-a concept-development project funded through Livermore's Physics Directorate and the Laboratory Directed Research and Development Program-could transport people or cargo, strike enemy targets, or help put satellites into space. "The fact that HyperSoar has many potential uses is key," says Carter. "Developing an entirely new aircraft is expensive. However, if there is a large market for such an aircraft, the cost per plane goes down. It's like the difference between a 747 and the Stealth bomber. There are hundreds of Boeing 747s being used by commercial airline companies, airfreight companies, and so on. But the only market for the Stealth is the military, which only needs a few. That's why you'll never see a Stealth being built for much less than they cost today."
Skipping on the Atmosphere
Beating the Heat|
Any object-airplane, spacecraft, asteroid-speeding through the atmosphere will compress and heat the air in front of it. This heat is inevitably absorbed by the surface of the object. "Heat buildup just kills most designs for hypersonic aircraft," Carter said. "The hotter the craft gets, the more material engineers add to the airframe to strengthen and shield it. Also, most other hypersonic concepts have trajectories that are strictly atmospheric, and the only way to get rid of the heat is to dump it into the fuel and then burn the fuel in the engines. The problem is, the faster you fly, the more fuel you must carry as a heat sink. Eventually, you end up carrying a significant amount of fuel just as a heat sink, and the engines end up running fuel-rich, that is, burning up more fuel than they really need. That's wasteful in and of itself. Also, more material and more fuel translate to more weight. After a while, the aircraft can no longer carry a decent cargo."
Because HyperSoar spends nearly two-thirds of its time out of the atmosphere, it can radiate the heat into space. Carter and colleagues at the University of Maryland have analyzed HyperSoar, compared it to other concepts, and found that-thanks to its trajectory and shape-HyperSoar has less heat load on its airframe and consumes less fuel.
From Espress Mail to Satellites
Flying the Paper Plane|
Even though HyperSoar is still in the "paper airplane" stage, it has garnered interest from organizations as diverse as Federal Express and STRATCOM (the U.S. Air Force Strategic Air Command). HyperSoar has appeared in Jane's Defence Weekly, Aviation Week and Space Technology, Scholastic's Weekly Reader, and daily papers from the Los Angeles Times to the Washington Times to local newspapers such as the Valley Times.
Passenger flight would be one of the last applications to become reality, but it is the one that the media and the public are most interested in. "The public gets very excited about space and air travel," said Carter. "To the general public, HyperSoar looks doable. The technology is nearly there, the concept is proven on paper. The thing now is to make it economically feasible to the defense and commercial communities so HyperSoar can get the funding it needs to take the next step in development."
Carter estimates that about $500 million would be needed to develop the technologies needed and build and test a 16-meter-long flyable unmanned prototype. Lawrence Livermore is positioned to help bring HyperSoar into reality because of its expertise in thermal protection materials, large-scale computational fluid dynamics, ultrahigh pressure testing design, and modeling the environmental effects of high-speed supersonic aircraft.
The question of funding aside, the day when passengers can hop a HyperSoar to London is still a ways off.
"When most people hear about HyperSoar," Carter added, "they immediately think big-building big airplanes to carry lots of passengers or cargo. But that's not economically feasible. I propose building small airplanes to justify the market and then building up from there, according to the need. That's how all the different flight technologies-airplanes, jets, helicopters-got started. It's the way that fledgling technologies like HyperSoar take wing."
Key Words: HyperSoar, hypersonic aircraft.
For further information contact Preston Carter (925) 423-8293 (firstname.lastname@example.org).