About four months after China revealed its plan to design a hypersonic passenger airliner, Boeing Commercial Airplanes (BCA) has decided to join the race for hypersonics by partnering with hypersonic specialists at the company’s Research & Technology unit to examine the feasibility of Mach 5 travel capable of crossing the Atlantic in 2 hours or the Pacific in 3.
According to Aviation Week, Boeing unveiled the initial concept vehicle at the American Institute of Aeronautics and Astronautics (AIAA) Aviation 2018 conference in Atlanta, Georgia. Although the hypersonic vehicle is in the early stages of design, the concept depicts a passenger capacity larger than long-range business jets, but much smaller than Boeing’s flagship 737, with indications the plane could enter service by the mid/late 2030s.
Boeing said the hypersonic aircraft could fly at Mach 5 with an altitude ceiling of 95,000 feet. That means this new vehicle would travel 2.5 times faster and 30,000 feet higher than the Aérospatiale/BAC Concorde, a British-French turbojet-powered supersonic passenger airliner, which operated from 1976 to 2003. Boeing touted the ability to operate the aircraft with same-day return flights from Asia and Europe, which would significantly increase asset utilization.
“You have to do these kinds of studies now to know where we have to push the technology and where we have to advance things,” said Boeing chief scientist for hypersonics Kevin Bowcutt, whose hypersonic research has been primarily in space and military applications.
“Technologically we could have an [operational military] hypersonic aircraft… flying in 10 years. But there’s a lot that goes into a commercial airplane, including the market, regulatory and environmental requirements, so it will happen when there is a convergence of those things,” Bowcutt explained.
Boeing determined that Mach 5 (3,836 mph) as the sweet spot between civil and non-transport military applications. “When you look at the problem of getting from Point A to Point B anywhere in the world, the question is how fast do you want to go and how fast is fast enough?” said Bowcutt.
“Supersonic isn’t really fast enough to go overseas and back in one day. For the business traveler or the military, where time is really important, that’s an interesting point. Mach 5 is where you can do that. You can get across the Atlantic in about 2 hr. and across the Pacific in about 3 hr,” said Bowcutt, who confirmed that a fierce race for hypersonic technologies is well underway among global superpowers.
Although sharing design features with Boeing’s proposed military hypersonic demonstrator, the commercial concept has an extended forward fuselage for greater cabin volume. (Source: Boeing)
“Our commercial airplane team has been working right alongside the BR&T [Boeing Research & Technology] team as this technology has evolved,” said Mike Sinnett, vice president of BCA product strategy and future airplane development. “We share our insight into the commercial market and where we see it going, as well as the requirements any commercial airplane would need to meet—ranging from passenger appeal to regulatory mandates.”
Both teams have “so far been looking at requirements and flight times,” adds Bowcutt. “And we have some of their advanced concept folks working shoulder-to-shoulder with us. We are trying to get to a point where we have a concept in which we are comfortable with the way the design closes, and then we can start looking at the market and at things like sonic boom and takeoff noise.”
In April, we covered the $247.5-million contract NASA awarded Lockheed Martin’s Skunk Works to design and build a low-boom X-plane that could lead to a new era of supersonic air travel in the next three to five years. While the technology is for Mach 1.5, there could be indications that the technology expected to hit the skies in 2021, could eventually be applied to hypersonic aircraft.
From supersonic to the sweet spot of Mach 5, it is the speed that dictates time for research and development. “To get from Mach 0.8 to Mach 5 is a sixfold [600%] increase in speed, but from Mach 5 to 6 is only a 20% increase. After Mach 5 you get diminishing returns and increasing costs, so what I am looking for are technical cliffs, or step changes. If you go much faster, eventually you are going to hit a step change in propulsion or materials,” explained Bowcutt. Boeing believes that it will have to adopt an advanced titanium airframe structure to sustain Mach 5 cruising speeds.
Bowcutt said the propulsion options for Mach 5 travel are limited. “We know we don’t need a scramjet because we can do it with a kind of turboramjet: a turbofan that transitions to a ramjet at Mach 5,’” he explained. Bowcutt also mentioned that cooling technology would be necessary for managing the thermal environment of the cabin and propulsion system.
As Aviation Week noted, Boeing will likely partner with one of the “big three” commercial engine-makers GE, Pratt & Whitney, and or Rolls Royce for the project.
Boeing could speed up the research of the development of the hypersonic airliner because of its vast knowledge of hypersonic technologies from its hypersonic waverider program. “We are doing a lot of that aero work right now, trying to look at what the theoretical limits of the lift/drag ratio are in cruise, and there are some key things we’ve learned about how to configure waveriders to get the right ratio, and to get high performance with an integrated propulsion system,” said Bowcutt.
Why should you care about hypersonic technologies?
Well, the era of hypersonic is now. Unbeknownst too many, the race for hypersonic aircraft and weapons have flourished among global superpowers (China, Russia, and the United States), who realize that the first to possess these technologies will revolutionize their civilian and military programs.
Video: Routine Hypersonic Flight: The Final Frontier of Aeronautics | Kevin Bowcutt