WHAT IF WE COULD SOLVE THE ‘HARD PROBLEM’
OF THE SONIC BOOM?
Solve the Physics.
Disruptive Aerospace Breakthrough Could Remake the Airline Industry: Supersonic Commercial Aircraft Now Possible Within FAA/EASA Acoustic Limits.
25 JAN 2018: SCIENCE AND TECHNOLOGY
When a British Airways Concorde travelling from New York touched down at Heathrow airport, in London, on October 24th 2003, supersonic passenger travel came to an end. Concorde was a technological marvel, but never a commercial success. Only 14 of them entered service. Yet the idea of building a successor has never quite gone away. Aircraft-makers review the idea from time to time. A number of groups are working on small executive jets intended to travel faster than the speed of sound. The trouble is, something else has also refused to go away: the shock wave known as a sonic boom that emanates from a supersonic aircraft.
That boom was one of Concorde’s failings. It rattled windows and frightened animals, which meant the plane’s flights over land were restricted to subsonic speeds. Throttling back an aircraft that is designed to fly fast is inefficient and causes it to guzzle a lot of fuel. If supersonic air travel is ever to return, Concorde’s successors will thus have to quieten their act.
Several groups are trying to do this by tweaking designs to take account of advances in aerodynamics. By 2021 NASA, America’s aerospace agency, hopes to fly a small experimental supersonic plane fitted with some of these modifications, such as a long, slender nose and engines blended into the fuselage. The agency expects this to reduce the sound of the shock wave to what it describes as a “low boom”. ButJohn Schlaerth, an aerospace engineer based in California, thinks he can take such modifications much further. He and his colleagues have filed for a patent on a set of designs which they believe might eliminate the boom’s sound altogether at ground level.
A sonic boom is the product of a series of shock waves arising from various parts of an aircraft—particularly its nose, wings and engines—as it flies faster than the speed of sound (1,240kph, 770mph or Mach 1, at sea level). Those waves are caused because air molecules cannot get out of the way fast enough during supersonic flight, and thus build up in front of these parts of the plane. The consequent change in pressure then propagates through the air and, when it reaches the ground, is heard as a distinctive boom.
Mr Schlaerth’s idea is to reflect and muffle the worst-offending waves. He would do this not by blending the engines into the fuselage, but rather by placing them well forward of the leading edge of the wing. That could be done either by mounting them on pylons extending from below the wing, or by attaching them to the fuselage. Both configurations would cause the engines’ exhaust plumes to reflect any shock wave forming in front of a wing upwards—ie, away from the ground.
Further shock waves, caused by the exhaust’s counter-reflection downwards by the wing’s wave, could be dealt with by modifying the engine casings to create a slower-moving stream of air below the plume. This slower air should form a boundary layer which, Mr Schlaerth says, would act as a “pneumatic cushion” that softened and impeded downward-propagating shock waves. The aircraft’s long nose, meanwhile, would be shaped to direct its shock waves upwards and sideways. Waves from the engine inlets would be directed upwards too; and put to good use. Adding an appropriate downward curve to a wing would trap the wave and create an area of high pressure that would give the wing additional lift.
To find out whether all this would work, Mr Schlaerth recruited two experts in computational fluid dynamics to act as independent consultants. Tim Colonius of the California Institute of Technology and Luigi Martinelli of Princeton University each carried out a series of tests. Using sophisticated computer modelling, one test found that the shock wave from the wing could be reduced by 63% at Mach 1.5, and that a similar reduction would be expected at Mach 2 (Concorde’s cruising speed). Another test showed that shock propagation below the engine was virtually non-existent. Further analysis, Mr Schlaerth says, indicates that the overall shock wave might be almost inaudible at ground level.
The next step is to replicate the computer tests using models in a wind tunnel, a task which the group hopes to take on later this year. Mr Schlaerth and his business partner, Mark Bryan, have founded a firm called New Century Transportation and Aeronautics Research to exploit the idea. If all goes well, it could lead to an experimental aircraft to demonstrate the technology.
Reducing sonic booms to an acceptable level would allow overland flights, which should make the return of supersonic passenger travel more plausible. Much would depend on the cost of building and operating such aircraft. But the prospect of being able to fly from New York to Los Angeles in less than two hours, instead of a tedious six or so, would be welcomed by many a weary traveller.
Air Traffic to Double 2018 to 2038
Market $6.3 Trillion
1/1000 = $6.3 Billion
Experienced Aerospace POC Team Grant/Investment remaining to Complete POC = $1.5M
Grant/Investment to Detailed Design = $9.5M
Detailed Design will be"Parts-Matched and Costed"
WHERE WE'RE AT:
Proof of Concept | 2D & 3D CFD MATCH THEORY
Wind-Tunnel Tests | Multiple Points by 12/2019
Patent-Pending | FILED SEPT 2015
International PTC | FILED SEPT 2017
Air Travel is Doubling.
FAA/Boeing/Airbus all predict global air traffic will double from 2018 to 2038.
Total market for commercial aircraft (20 years) = $6.3 Trillion USD.
Aircraft design is limited by a 50-year-old conventional approach.
Commercial-scale supersonic flight will address global passenger needs.
Rethink the traditional approach to aircraft; invent new fuselage, wing geometry, & engines.
Protect IP; apply for US and foreign utility patents; achieve early proof of concept.
Gather experts in a private effort (outside their institutional roles or tools) to confirm POC .
Solve the ‘hard’ problem to allow scale up to large SS aircraft and SS flights over land.
Locate the right people at the right partner to avoid ‘NIH’ syndrome -- and move really fast.
Meet The Team
John Schlaerth Jr.
Inventor, Aerospace Engineer MS, MBA, USC. Founder, John worked during engineering school for a group of Caltech Faculty determined to solve the ‘hard’ problem of the sonic boom; they never solved it. John went on to a 30-year career in other areas for Hughes, Boeing, and others. Until…a eureka moment in 2014.
Professor of Engineering, Caltech, Pasadena. Tim ran our initial POC experiments, his contribution is on-going. Tim is an expert in fluid dynamics and computational measurements of extreme shock wave behaviour.
Aerospace design/build/test engineer. Ron grew up in aerospace and was CEO of a $2B aircraft manufacturing consortium that supplied military and commercial OEM’s. He is a specialist in M&A having acquired and sold over 40 aerospace companies
Gigi is assistant professor of aerospace engineering at
Princeton. He is a specialist in fluid dynamics. He teaches Aerodynamics, and Mathematics.
Start-up issues, strategic plan, onboard team. Mark is in charge of start-up strategy, the build of our 1st tier POC team and funding. He consults on innovation for Fortune 500 as well as Global NGOs.
Jim is an aerospace engineer and patent lawyer with a speciality in aerospace intellectual Property Protection. Jim is advising us about potential strategic partners.
Tim Colonius, Ph.D. Proof of Concept
Acting COO Design/Build
Luigi Martinelli, Ph.D. Proof of Concept
Anita Sengupta, Ph.D. Proof of Concept
Anita is assistant professor of aerospace engineering at USC. She led development of the supersonic parachute for the Mars rover Curiosity. She is a specialist in computational fluid dynamics, wind tunnel testing, and modeling.
Strategy & Funding
Brian is a pilot and aerospace engineer. He began his career flight testing for Boeing before spending 20 years as CMO for Dassault/Falcon.
Brian writes regularly about aerospace for Forbes.