Philosophical Society of Washington

Minutes of the 2369th Meeting

At the Cosmos Club, Washington, DC
November 18, 2016

President Larry Millstein called the 2369th meeting of the Society to order at 8:36 p.m.  He announced the order of business and welcomed new members.  The minutes of the previous meeting were read and approved.  President Millstein presented a summary of the 31st meeting of the Society, held in 1872. President Millstein then introduced the speaker for the evening, Jaiwon Shin, the Associate Administrator in the Aeronautics Research Mission Directorate at NASA. His lecture was titled “Exciting Possibilities for 21st Century Aviation: NASA's X-Plane Program”.

Dr. Shin began by reminding the audience that the precursor organization to NASA’s Aeronautics mission was founded in 1915, a few years after the Wright Brothers’ first flight, thus predating NASA’s better known Space mission by decades. Dr. Shin explained that NASA Aeronautics research is responsible for many of the advances that helped bring civil and military aviation from the Wright Flyer into the modern era.

Dr. Shin then showed a recording of the current daily commercial air traffic plotted through the US airspace, comprising up to 5,000 planes at once. He explained that every flight needs to be managed within defined airways with strict separation and precise landing and takeoff times. Modern aviation safety and air traffic control procedures have made flying so safe that an individual taking a three hour commercial flight every day would expect to fly for 9,000 years without experiencing a fatal accident, making it the safest mode of transportation in the world.

Another area that NASA is collaborating with the private sector to research is ultra-efficient, environmentally responsible aircraft. Technologies such as composite wings and fuselages, saw-tooth exhaust nozzles, and non-circular fuselages provide substantial weight savings, as well as improving fuel efficiency and reducing noise. Dr. Shin explained that the near-term development and adoption of these technologies could decrease the fuel consumption of the U.S. commercial fleet by billions of gallons of fuel by 2050. 

Dr. Shin next discussed what he called the “dawn of a new era” of aviation using composite materials to move beyond the performance limits of the current “tube and wing” airframe design. Future designs being investigated include very long truss-braced wings with non-circular fuselages and “flying wing” designs, all to maximize the effective lift area and engine size while mitigating engine noise. Unusual engine configurations, such as placing them at the top rear of the aircraft, may further increase efficiency by consuming the “boundary layer” air that is closest to the fuselage and thus creates much of the aircraft drag, if engines can be made to operate using the disrupted air.

Dr. Shin noted that the increasing demands for high efficiency, low emissions, and reduced noise mean that aircraft designers will soon need to find ways to incorporate electric-based propulsion into their planes. Although the weight of lithium-ion batteries is currently prohibitive, early hybrid designs may be ready for flight test as soon as 2018.

Dr. Shin then discussed the polarizing subject of supersonic flight. The 20th century landmark for commercial supersonic flight, the Concorde, was incredibly loud, dirty, and expensive. If supersonic flight is to be resumed, these problems must be addressed. Indeed, due to the disruption and potential damage from sonic booms, commercial supersonic flight over land is currently banned in all countries. NASA has modeled variations on wing designs to create “low-boom” aircraft, and is targeting 2020 for the first flight tests.

Dr. Shin also addressed the parallel development of Unmanned Aerial Systems, or drones and the race for safe integration of UAS into the national airspace. UAS policy issues include not only safe operation, noise, and wireless spectrum, but also privacy and security concerns, and simple social acceptance. Dr. Shin noted that the stakes in this race are enormous, because whichever country achieves such integration will reap enormous economic benefits through the availability of new services and efficiency improvements, as well as the sale of UAS hardware as the rest of the world follows suit.

Dr. Shin concluded by repeating that the sky is the limit as myriad new aircraft design and propulsion technologies are poised to usher in a new era of flight and new opportunities for US leadership.

After the conclusion of the talk, President Millstein invited questions from the audience.

Several questioners asked for more information about hypersonic flight. Dr. Shin explained that Mach 5, or five times faster than the speed of sound, is traditionally considered the threshold to hypersonic speed. The current airspeed record for jet-propelled aircraft is held by NASA’s unmanned X-43, which achieved Mach 9.7, or approximately 7,400 miles per hour…for ten seconds. One major application of hypersonic engineering would be building spacecraft that can take off and land horizontally, like airplanes, creating tremendous efficiency gains and lowering the cost to orbit.

After the question and answer period, President Millstein thanked the speaker, made the usual housekeeping announcements, and invited guests to join the Society.  At 10:37 p.m., President Millstein adjourned the 2369th meeting of the Society to the social hour.

Attendance: 68
The weather: Clear
The temperature: 11°C

Respectfully submitted,

Preston Thomas
External Communications Director

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