The NASA/MIT D8 airliner for 2030
The NASA/MIT D8 airliner for 2030

How does a ‘virtual window’ for passengers, or a cockpit where the pilots fly lying prone grab you.

Or a total of 25 seats across in a flying manta ray blended wing body airliner.

A NASA funded program to identify advanced airliner concepts for the 2030s has produced five subsonic designs that address tough rules for lower greenhouse gas emissions (70% less fuel burn) and noise levels (71 decibels lower than a current model 737).

The MIT blended wing body mid sized long haul proposal
The MIT blended wing body mid sized long haul proposal

They also propose some very radical innovations despite two of the designs from a GE and Northrop Grumman team looking just like current airliners…at first glance, while Boeing has proposed a hybrid battery and liquid fuel 154 seat turbine that uses a strut reinforced wing similar to those used in high wing monoplanes in the 1930s.

Boeing/NASA image of the SUGAR Volt hybrid electric-kerosene 154 seater
Boeing/NASA image of the SUGAR Volt hybrid electric-kerosene 154 seater

NASA also contracted for domestic designs that could use the 1500 metre runways of metropolitan general aviation airfields and take pressure off America’s congested longer runway equipped hub airports.

A Massachusetts Institute of Technology team, supported by engine maker Pratt and Whitney, came up with two designs, the D8 double bubble transcontinental US design shown in the headline graphic, and the H3 series based on a blended wing body or BWB concept with non-stop trans Pacific capabilities.

The D8 has the same 180 seat all economy capacity as the baseline Boeing 737-800 used in its study, but the seats are roomier and eight across in a twin aisle cabin in a jet that would fly around 10% slower than typical single aisle jets today but be much faster to turn between flights.

It uses three ducted tail mounted engines, which also masks noise below its flight paths.

The MIT domestic D8 features
The MIT domestic D8 engine technology ambitions

The MIT teams H3 design is intriguing for many reasons, including its cautious embracing of the BWB concept. The design is reinforced internally with four walls, creating five distinct tubular cabins each five across in economy, to overcome the structural stresses caused by the tendency of pressurized structures to ovalise, and deteriorate as proved to be the case with the Section 41 issues in high cycle Boeing 747s. It would be like flying in five parallel joined DC-9s, and the turning moment in the outermost seats during turbulence or even minor course adjustments would be a major thrill ride experience.

The other teams, lead by Boeing, GE and Northrop Grumman all consider BWB options in their detailed documentation, but dismissed them as sub-optimal.

The long and detailed presentations by each of the teams are worth the hours it takes to follow them if you are interested in aero-engineering, risk analysis, and closely reasoned estimates about where materials, systems, engines and fuel technology will take airliner design in the next 20 years.

However NASA, as usual, is having trouble with consistent reliable website links so to access them it might be best to go to its media release here and then scroll to the presentation PDF links at the bottom of the page.

Boeing’s SUGAR Volt design does look a bit like Mary Poppin’s bonnet from some angles with its strut reinforced wide thin high wing but this 154 seat twin turbine is a seriously argued hybrid electric-liquid fuelled airliner.

Boeing graphic: How do you like your SUGAR?
Boeing graphic: How do you like your SUGAR?

SUGAR stands for Subsonic Ultra Green Aircraft Research. A lot of words are spent with cute terminology concerning other SUGAR derivatives, like raw-SUGAR but the analysis rises above this irritation.

NASA/Boeing slide of the general battery locations on the SUGAR Volt
NASA/Boeing slide of the general battery locations on the SUGAR Volt

The power plant, which Boeing considers as both an open or ducted rotor, can run using batteries to turn the turbine when the fuel burning core is shut down, or idle.

Boeing predicts that battery technology in the ’30s will provide performance levels unavailable today, but achievable in the medium term.

The SUGAR-Volt is intended to be capable flying shorter distances almost entirely on its batteries.

General summary of battery options for hybrid designs, Boeing graphic
General summary of battery options for hybrid designs, Boeing graphic

Boeing also proposed an optimal cruise speed of Mach 0.6 (slow) if liquid fuel is expensive, or up to Mach 0.8 if it is cheap.

Northrop Grumman graphic of its SELECT short field 120 pax jet
Northrop Grumman graphic of its SELECT short field 120 pax jet

The Northrop Grumman SELECT project looks at first glance to be a current 737, but with more clearance for the engines. The acronym means Silent Efficient Low Emissions Commercial Transport.

The most interesting thing about SELECT could be the process of elimination its team undertook before arriving at a 120 seat proposal that looks just like a 737 today from anything but very close range.

The concepts Northrop Grumman rejected above and below in making a SELECTion.
The concepts Northrop Grumman rejected above and below in making a SELECTion.

NG design space

The GE-Cessna-Georgia Tech team have come up with the most interesting predictions for a back-the-future design.

The GE-Cessna-Georgia Tech model, all windows are 'painted' on
The GE-Cessna-Georgia Tech model, all windows are 'painted' on

This is a 20 seat shortish (1800 kilometres) range high wing turbo-prop that fits in where the Twin Otter (which although under renewed limited construction) left off as a mass produced commuter airliner many years ago.

But it takes small commuter airliner concepts further. The tear shaped high performance turbo-prop and its ovaloid four across cabin is designed to hold laminar (super slippery) airflow across much of its surface area, so much so that the cockpit and passenger windows are ‘virtual’, covered in the same next generation composite skin that encases the lines of fasteners seen on the 787.

The GE team's commuter flight solution for 2030-2035
The GE team's commuter flight solution for 2030-2035

This skin is to contain the external paint and the lightning conductivity which has been such an issue on the 787 (see diagram below.)

GE team view of composites now and in the future
GE team view of composites now and in the future

The FAA Part 121 airliner will have two pilots and one cabin crew. The pilots lie prone on reclining seats to enable a sleeker shaped nose, and see the world, like the passengers on an ultra high definition LED type window.

Let’s hope the virtual passenger window view is not taken from a forward looking tail mounted camera. Imagine the disorientation of feeling forward acceleration but seeing the external visual cues heading toward you from the side!

The maximum field length for the GE team design is only 1100 metres, but the turbo-prop power plant will be capable of Mach 0.55 at 12,000 metres, a combination of cruising speed and altitude not approached by turbo-prop airliners today.

The GE team estimate that the technologies needed to make their deceptively conventional looking design a reality are only 60% in place today, but within reach of being sufficiently mature and reliable for operations from 2030.

If only this was available for Moorabbin or Bankstown now, before they become big box retail precincts, or whatever else they get sold for before the ‘thirties come.

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